feat: implement swarm mode for multi-agent coordination

.gitignore

@@ -47,3 +47,7 @@ dist/
 
 # Windows Application Icon/Resource
 *.syso
+
+# PM2 and process manager configs (dev-specific)
+ecosystem.config.js
+.pm2/

cmd/picoclaw/internal/gateway/command.go

@@ -6,6 +6,7 @@ import (
 
 func NewGatewayCommand() *cobra.Command {
 	var debug bool
+	var configPath string
 
 	cmd := &cobra.Command{
 		Use:     "gateway",
@@ -13,11 +14,12 @@ func NewGatewayCommand() *cobra.Command {
 		Short:   "Start picoclaw gateway",
 		Args:    cobra.NoArgs,
 		RunE: func(_ *cobra.Command, _ []string) error {
-			return gatewayCmd(debug)
+			return gatewayCmd(debug, configPath)
 		},
 	}
 
 	cmd.Flags().BoolVarP(&debug, "debug", "d", false, "Enable debug logging")
+	cmd.Flags().StringVarP(&configPath, "config", "c", "", "Path to config file")
 
 	return cmd
 }

cmd/picoclaw/internal/gateway/helpers.go

@@ -39,13 +39,13 @@ import (
 	"github.com/sipeed/picoclaw/pkg/voice"
 )
 
-func gatewayCmd(debug bool) error {
+func gatewayCmd(debug bool, configPath string) error {
 	if debug {
 		logger.SetLevel(logger.DEBUG)
 		fmt.Println("🔍 Debug mode enabled")
 	}
 
-	cfg, err := internal.LoadConfig()
+	cfg, err := loadConfigWithPath(configPath)
 	if err != nil {
 		return fmt.Errorf("error loading config: %w", err)
 	}
@@ -252,3 +252,12 @@ func setupCronTool(
 
 	return cronService
 }
+
+func loadConfigWithPath(configPath string) (*config.Config, error) {
+	path := configPath
+	if path == "" {
+		path = internal.GetConfigPath()
+	}
+	fmt.Printf("📁 Loading config from: %s\n", path)
+	return config.LoadConfig(path)
+}

docs/swarm-architecture.md

@@ -0,0 +1,572 @@
+# PicoClaw Swarm Mode Architecture
+
+## Overview
+
+PicoClaw Swarm Mode enables multiple PicoClaw instances to work together as a distributed system, providing:
+- **Node Discovery**: Automatic peer discovery via NATS JetStream KV with TTL-based liveness
+- **Health Monitoring**: Heartbeat renewal with configurable TTL and failure detection
+- **Load Balancing**: Intelligent task distribution based on node load scoring
+- **Handoff Mechanism**: Dynamic task delegation via NATS request-reply
+- **Leader Election**: Distributed leader election via KV CAS (Compare-And-Swap) lock
+
+**Transport**: All swarm communication uses NATS as the sole transport layer. There is no UDP gossip, no custom RPC, and no unencrypted channels.
+
+## Architecture
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                        PicoClaw Swarm                           │
+│                     (NATS as sole transport)                    │
+├─────────────────────────────────────────────────────────────────┤
+│  Control Plane                   │  Data Plane                  │
+│  ├─ Node Discovery (KV + TTL)   │  ├─ Task Execution           │
+│  ├─ Membership Management       │  ├─ Session Transfer          │
+│  ├─ Health Monitoring            │  │   (NATS request-reply)     │
+│  ├─ Load Monitoring              │  └─ Message Routing           │
+│  └─ Leader Election (KV CAS)    │      (targeted subjects)      │
+└─────────────────────────────────────────────────────────────────┘
+```
+
+## NATS Subject Namespace
+
+All swarm messages are published under a common subject prefix. NATS ACL rules should restrict `picoclaw.swarm.>` to authenticated swarm node identities only.
+
+| Subject Pattern | Purpose |
+|-----------------|---------|
+| `picoclaw.swarm.heartbeat.<nodeID>` | Heartbeat / KV renewal |
+| `picoclaw.swarm.node.<nodeID>.msg` | Direct node messaging (request-reply) |
+| `picoclaw.swarm.handoff.<nodeID>` | Targeted handoff requests (request-reply) |
+| `picoclaw.swarm.leader` | Leader election announcements |
+| `picoclaw.swarm.metrics.<nodeID>` | Metrics publishing |
+
+## JetStream KV Buckets
+
+| Bucket | Key Pattern | TTL | Purpose |
+|--------|-------------|-----|---------|
+| `swarm_members` | `node.<nodeID>` | 15s (configurable) | Membership liveness via TTL expiry |
+| `swarm_status` | `status.<nodeID>` | 30s | Detailed node status cache (CPU, mem, tasks) |
+| `swarm_leader` | `leader` | 10s | Leader election CAS lock |
+
+## Control Plane
+
+### 1. Node Discovery
+
+Nodes discover each other by writing entries to the `swarm_members` KV bucket and watching for changes. Liveness is determined by TTL — if a node stops renewing its entry, the key expires and the node is considered dead.
+
+```mermaid
+sequenceDiagram
+    participant Node1
+    participant NATS as NATS JetStream KV
+    participant Node2
+
+    Note over Node1: New node starts
+    Node1->>NATS: KV Put (node.node-1, NodeInfo, TTL=15s)
+    Node1->>NATS: KV Watch (swarm_members.>)
+    Node2->>NATS: KV Put (node.node-2, NodeInfo, TTL=15s)
+    NATS-->>Node1: Watch event: node.node-2 created
+    NATS-->>Node2: Watch event: node.node-1 exists
+    Note over Node1,Node2: Cluster formed
+
+    loop Every heartbeat_interval (5s)
+        Node1->>NATS: KV Put (renew TTL)
+        Node2->>NATS: KV Put (renew TTL)
+    end
+
+    Note over Node1: Node1 crashes
+    NATS-->>Node2: Watch event: node.node-1 expired (TTL)
+    Note over Node2: Mark Node1 as dead
+```
+
+**Key Parameters:**
+
+| Parameter | Default | Description |
+|-----------|---------|-------------|
+| `heartbeat_interval` | 5s | Frequency of KV entry renewal |
+| `member_ttl` | 15s | TTL for member entries (must be > heartbeat_interval) |
+| `node_timeout` | 5s | Time before marking node as suspect |
+| `dead_node_timeout` | 30s | Time before removing dead node from view |
+
+### 2. Membership Management
+
+Each node maintains a local `ClusterView` populated by KV watch events:
+
+```go
+type ClusterView struct {
+    sync.RWMutex
+    localNode  *NodeInfo
+    members    map[string]*NodeWithState  // node_id -> NodeWithState
+    Size       int
+}
+```
+
+**Node State Machine:**
+
+```mermaid
+stateDiagram-v2
+    [*] --> Alive: KV entry created
+    Alive --> Suspect: Heartbeat not renewed within node_timeout
+    Suspect --> Alive: KV entry renewed
+    Suspect --> Dead: KV entry expired (TTL)
+    Dead --> [*]: Removed from view
+    Alive --> Left: Node gracefully stops (deletes KV entry)
+    Left --> [*]
+```
+
+**Node Information:**
+
+```go
+type NodeInfo struct {
+    ID        string            // Unique node identifier
+    Addr      string            // IP address
+    Port      int               // Service port
+    AgentCaps map[string]string // Capabilities (models, tools)
+    LoadScore float64           // Current load (0.0-1.0)
+    Labels    map[string]string // Custom labels
+    Timestamp int64             // Last update time (UnixNano)
+    Version   string            // Protocol version
+}
+```
+
+### 3. Health Monitoring
+
+Health is driven by KV TTL — no separate probe/ping mechanism is needed:
+
+```mermaid
+sequenceDiagram
+    participant Node as Node
+    participant KV as NATS KV (swarm_members)
+    participant Watcher as Other Nodes (KV Watch)
+
+    loop Every heartbeat_interval
+        Node->>KV: Put (node.<id>, NodeInfo, TTL=15s)
+        KV-->>Watcher: Watch event: key updated
+        Watcher->>Watcher: Update LastSeen, mark Alive
+    end
+
+    Note over Node: Node stops renewing
+    KV->>KV: TTL expires, key deleted
+    KV-->>Watcher: Watch event: key deleted
+    Watcher->>Watcher: Mark as Dead, dispatch NodeLeft event
+```
+
+### 4. Load Monitoring
+
+Each node continuously monitors its resource usage (transport-agnostic):
+
+```mermaid
+graph TB
+    subgraph Load Monitor
+        A[CPU Sample] --> D[Score Calculator]
+        B[Memory Sample] --> D
+        C[Session Count] --> D
+        D --> E[Load Score]
+    end
+
+    subgraph Weights
+        A -.->|0.3| D
+        B -.->|0.3| D
+        C -.->|0.4| D
+    end
+
+    E --> F{Threshold Check}
+    F -->|< 0.8| G[Normal Mode]
+    F -->|>= 0.8| H[Overloaded - Trigger Handoff]
+```
+
+**Load Score Formula:**
+
+```
+LoadScore = (CPUUsage * cpu_weight) +
+            (MemoryUsage * memory_weight) +
+            (SessionRatio * session_weight)
+
+Where:
+- CPUUsage = current CPU usage (0.0-1.0)
+- MemoryUsage = current memory usage (0.0-1.0)
+- SessionRatio = current_sessions / max_sessions
+- Default weights: cpu=0.3, memory=0.3, session=0.4
+```
+
+### 5. Leader Election
+
+Leader election uses a CAS (Compare-And-Swap) lock on the `swarm_leader` KV bucket:
+
+```mermaid
+sequenceDiagram
+    participant NodeA
+    participant KV as NATS KV (swarm_leader)
+    participant NodeB
+
+    NodeA->>KV: Create("leader", {nodeID: A}, TTL=10s)
+    KV-->>NodeA: OK (revision=1)
+    Note over NodeA: Becomes leader
+
+    NodeB->>KV: Create("leader", {nodeID: B}, TTL=10s)
+    KV-->>NodeB: Key exists (conflict)
+    NodeB->>KV: Watch("leader")
+    Note over NodeB: Becomes follower, watches for changes
+
+    loop Every renewal_interval (3s)
+        NodeA->>KV: Update("leader", {nodeID: A}, revision=N)
+        KV-->>NodeA: OK (revision=N+1)
+    end
+
+    Note over NodeA: NodeA crashes, stops renewing
+    KV->>KV: TTL expires, key deleted
+    KV-->>NodeB: Watch event: "leader" deleted
+    NodeB->>KV: Create("leader", {nodeID: B}, TTL=10s)
+    KV-->>NodeB: OK
+    Note over NodeB: Becomes new leader
+```
+
+## Data Plane
+
+### 1. Request Routing
+
+Inter-node messages use NATS request-reply on targeted subjects:
+
+```mermaid
+sequenceDiagram
+    participant User
+    participant N1 as Node 1
+    participant NATS
+    participant N2 as Node 2
+
+    User->>N1: Message
+    N1->>N1: Check local load
+
+    alt Load OK
+        N1->>N1: Process locally
+        N1->>User: Response
+    else Overloaded
+        N1->>NATS: Request on picoclaw.swarm.node.N2.msg
+        NATS->>N2: Deliver request
+        N2->>NATS: Reply with response
+        NATS->>N1: Deliver reply
+        N1->>User: Response (from N2)
+    end
+```
+
+### 2. Handoff Mechanism
+
+**Handoff Decision Flow:**
+
+```mermaid
+flowchart TD
+    A[Receive Request] --> B{Should Handoff?}
+    B -->|Local load >= threshold| C[Select Target Node]
+    B -->|Local load < threshold| D[Process Locally]
+
+    C --> E{Target Available?}
+    E -->|Yes| F[NATS Request to target]
+    E -->|No| G[Retry or Fail]
+
+    F --> H[Target validates & processes]
+    H --> I{Reply received?}
+    I -->|Yes, accepted| J[Return target's response]
+    I -->|Timeout| K[Retry next node or fail]
+```
+
+**Handoff Protocol (NATS request-reply):**
+
+```mermaid
+sequenceDiagram
+    participant Source as Overloaded Node
+    participant NATS
+    participant Target as Selected Node
+
+    Source->>Source: Check load threshold
+    Source->>NATS: Request on picoclaw.swarm.handoff.<targetID>
+    NATS->>Target: Deliver HandoffRequest
+
+    Target->>Target: Validate (load OK? can handle?)
+    alt Accepted
+        Target->>Target: Process request
+        Target->>NATS: Reply: HandoffResponse{accepted, result}
+        NATS->>Source: Deliver reply
+        Source->>Source: Return result to caller
+    else Rejected
+        Target->>NATS: Reply: HandoffResponse{rejected, reason}
+        NATS->>Source: Deliver rejection
+        Source->>Source: Try next node or process locally
+    end
+```
+
+### 3. Direct Node Messaging
+
+Nodes can send arbitrary messages to specific peers using NATS request-reply:
+
+```
+Subject: picoclaw.swarm.node.<targetNodeID>.msg
+Payload: JSON {action, message, channel, chat_id, sender_id, trace_id}
+Reply:   JSON {response} or {error}
+```
+
+Context parameters (`channel`, `chat_id`, `sender_id`, `trace_id`) enable cross-node audit trails and conversation continuity.
+
+## System Architecture
+
+### Component Overview
+
+```mermaid
+graph TB
+    subgraph "Node 1"
+        D1[Discovery Service] --> M1[Membership Manager]
+        H1[Handoff Coordinator] --> M1
+        L1[Load Monitor] --> H1
+        LE1[Leader Election] --> D1
+        A1[Agent Loop] --> L1
+    end
+
+    subgraph "Node 2"
+        D2[Discovery Service] --> M2[Membership Manager]
+        H2[Handoff Coordinator] --> M2
+        L2[Load Monitor] --> H2
+        LE2[Leader Election] --> D2
+        A2[Agent Loop] --> L2
+    end
+
+    subgraph NATS["NATS Server (JetStream)"]
+        KV1[KV: swarm_members]
+        KV2[KV: swarm_status]
+        KV3[KV: swarm_leader]
+        SUB[Subjects: picoclaw.swarm.*]
+    end
+
+    D1 <-->|KV Watch + Put| KV1
+    D2 <-->|KV Watch + Put| KV1
+    H1 <-->|Request-Reply| SUB
+    H2 <-->|Request-Reply| SUB
+    LE1 <-->|CAS Lock| KV3
+    LE2 <-->|CAS Lock| KV3
+```
+
+### Communication Channels
+
+| Channel | Protocol | Purpose |
+|---------|----------|---------|
+| Discovery | NATS KV (JetStream) | Membership liveness via TTL |
+| Status Cache | NATS KV (JetStream) | Detailed node status (CPU, mem, tasks) |
+| Leader Election | NATS KV CAS (JetStream) | Distributed leader lock |
+| Handoff | NATS request-reply | Session transfer coordination |
+| Node Messaging | NATS request-reply | Direct inter-node messages |
+| Metrics | NATS publish | Observability data |
+
+## Configuration
+
+### Example Configuration
+
+```json
+{
+  "swarm": {
+    "enabled": true,
+    "node_id": "picoclaw-node-1",
+
+    "discovery": {
+      "nats_url": "nats://nats.example.com:4222",
+      "nats_creds_file": "/etc/picoclaw/nats.creds",
+      "nats_tls_cert": "/etc/picoclaw/client-cert.pem",
+      "nats_tls_key": "/etc/picoclaw/client-key.pem",
+      "nats_tls_ca_cert": "/etc/picoclaw/ca.pem",
+      "heartbeat_interval": "5s",
+      "member_ttl": "15s",
+      "node_timeout": "5s",
+      "dead_node_timeout": "30s"
+    },
+
+    "handoff": {
+      "enabled": true,
+      "load_threshold": 0.8,
+      "timeout": "30s",
+      "max_retries": 3,
+      "retry_delay": "5s",
+      "request_timeout": "10s"
+    },
+
+    "load_monitor": {
+      "enabled": true,
+      "interval": "5s",
+      "sample_size": 60,
+      "cpu_weight": 0.3,
+      "memory_weight": 0.3,
+      "session_weight": 0.4
+    },
+
+    "leader_election": {
+      "enabled": false,
+      "lock_ttl": "10s",
+      "renewal_interval": "3s"
+    }
+  }
+}
+```
+
+### Minimal Two-Node Setup
+
+**1. Start NATS with JetStream:**
+
+```bash
+docker run -d --name nats \
+  -p 4222:4222 \
+  nats:latest -js
+```
+
+**2. Node 1 config (`node1.json`):**
+
+```json
+{
+  "swarm": {
+    "enabled": true,
+    "node_id": "node-1",
+    "discovery": {
+      "nats_url": "nats://localhost:4222"
+    }
+  }
+}
+```
+
+**3. Node 2 config (`node2.json`):**
+
+```json
+{
+  "swarm": {
+    "enabled": true,
+    "node_id": "node-2",
+    "discovery": {
+      "nats_url": "nats://localhost:4222"
+    }
+  }
+}
+```
+
+**4. Verify cluster:**
+
+Once both nodes start, each should discover the other via KV watch within one `heartbeat_interval` (5s). Use the `swarm_nodes` tool or `/nodes` command to verify membership.
+
+### Deployment Modes
+
+**Single Entry Point:**
+
+```mermaid
+graph LR
+    TG[Telegram Gateway] --> N1[Node 1: Leader]
+    N1 <-->|NATS| N2[Node 2: Worker]
+    N1 <-->|NATS| N3[Node 3: Worker]
+```
+
+**Multi-Entry Point (with load balancer):**
+
+```mermaid
+graph LR
+    LB[Load Balancer] --> N1[Node 1]
+    LB --> N2[Node 2]
+    N1 <-->|NATS Mesh| N2
+    N1 <-->|NATS Mesh| N3[Node 3]
+    N2 <-->|NATS Mesh| N3
+```
+
+## Event System
+
+The swarm publishes events for monitoring and integration:
+
+```mermaid
+graph LR
+    A[Node Joined] --> ED[Event Dispatcher]
+    B[Node Left] --> ED
+    C[Node Suspect] --> ED
+    D[Leader Changed] --> ED
+    E[Handoff Started] --> ED
+    F[Handoff Completed] --> ED
+
+    ED --> H[Handlers]
+    H --> L[Logging]
+    H --> M[Metrics]
+    H --> U[Custom Actions]
+```
+
+**Event Types:**
+
+| Event | Description | Payload |
+|-------|-------------|---------|
+| `NodeJoined` | New node discovered via KV watch | NodeInfo |
+| `NodeLeft` | Node KV entry expired or deleted | NodeID |
+| `NodeSuspect` | Node heartbeat overdue | NodeID |
+| `NodeAlive` | Node recovered (KV entry renewed) | NodeInfo |
+| `LeaderChanged` | Leader election result changed | LeaderID |
+| `HandoffStarted` | Handoff initiated | HandoffOperation |
+| `HandoffCompleted` | Handoff finished | HandoffResult |
+| `HandoffFailed` | Handoff error | Error |
+
+## Error Handling
+
+```mermaid
+flowchart TD
+    A[Operation Failed] --> B{Retryable?}
+    B -->|Yes| C[Increment retry count]
+    B -->|No| D[Return error immediately]
+
+    C --> E{Max retries reached?}
+    E -->|No| F[Wait retry_delay]
+    F --> G[Retry operation]
+
+    E -->|Yes| H[Mark node suspect]
+    H --> I[Select alternative node]
+
+    G --> J{Success?}
+    J -->|Yes| K[Continue]
+    J -->|No| C
+```
+
+## Security
+
+### Threat Model
+
+PicoClaw Swarm assumes nodes are deployed in a **trusted or semi-trusted network**. The NATS server is the single trust boundary.
+
+| Concern | Mitigation |
+|---------|------------|
+| **Transport encryption** | NATS TLS (configure `nats_tls_*` options) |
+| **Node authentication** | NATS credentials file (NKeys/JWT) or mTLS client certs |
+| **Subject authorization** | NATS ACL: restrict `picoclaw.swarm.>` to swarm node identities |
+| **Inter-node message integrity** | NATS connection-level TLS ensures no tampering |
+| **Unauthorized KV access** | JetStream permissions: only swarm nodes can read/write swarm KV buckets |
+
+### Production Recommendations
+
+1. **Always enable TLS** — set `nats_tls_cert`, `nats_tls_key`, `nats_tls_ca_cert`
+2. **Use NKeys or JWT credentials** — set `nats_creds_file` for per-node identity
+3. **Configure NATS ACLs** — restrict `picoclaw.swarm.>` publish/subscribe to swarm accounts
+4. **Network isolation** — NATS port (4222) should not be exposed to public internet
+5. **Rotate credentials** — use short-lived JWTs with NATS account server for production
+
+### Minimal Secure NATS Configuration
+
+```conf
+# nats-server.conf
+listen: 0.0.0.0:4222
+jetstream: enabled
+
+tls {
+  cert_file: "/etc/nats/server-cert.pem"
+  key_file:  "/etc/nats/server-key.pem"
+  ca_file:   "/etc/nats/ca.pem"
+  verify:    true  # require client certs (mTLS)
+}
+
+authorization {
+  swarm_user = {
+    publish = ["picoclaw.swarm.>", "$JS.API.>"]
+    subscribe = ["picoclaw.swarm.>", "_INBOX.>"]
+  }
+  users = [
+    { nkey: "UABC...", permissions: $swarm_user }
+  ]
+}
+```
+
+## Future Enhancements
+
+1. **Consistent Hashing**: Route requests to stable node assignments for session affinity
+2. **Multi-Region**: Geo-distributed clusters with region-aware subject prefixes
+3. **Graceful Draining**: Leader-coordinated node shutdown with session migration
+4. **Observability**: Prometheus metrics endpoint for swarm health (connection count, handoff latency, leader changes)

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/mdp/qrterminal/v3 v3.2.1
 	github.com/modelcontextprotocol/go-sdk v1.3.0
 	github.com/mymmrac/telego v1.6.0
+	github.com/nats-io/nats.go v1.49.0
 	github.com/open-dingtalk/dingtalk-stream-sdk-go v0.9.1
 	github.com/openai/openai-go/v3 v3.22.0
 	github.com/rivo/tview v0.42.0
@@ -42,6 +43,8 @@ require (
 	github.com/lucasb-eyer/go-colorful v1.3.0 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/nats-io/nkeys v0.4.12 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/petermattis/goid v0.0.0-20260113132338-7c7de50cc741 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect

go.sum

@@ -138,6 +138,12 @@ github.com/modelcontextprotocol/go-sdk v1.3.0 h1:gMfZkv3DzQF5q/DcQePo5rahEY+sguy
 github.com/modelcontextprotocol/go-sdk v1.3.0/go.mod h1:AnQ//Qc6+4nIyyrB4cxBU7UW9VibK4iOZBeyP/rF1IE=
 github.com/mymmrac/telego v1.6.0 h1:Zc8rgyHozvd/7ZgyrigyHdAF9koHYMfilYfyB6wlFC0=
 github.com/mymmrac/telego v1.6.0/go.mod h1:xt6ZWA8zi8KmuzryE1ImEdl9JSwjHNpM4yhC7D8hU4Y=
+github.com/nats-io/nats.go v1.49.0 h1:yh/WvY59gXqYpgl33ZI+XoVPKyut/IcEaqtsiuTJpoE=
+github.com/nats-io/nats.go v1.49.0/go.mod h1:fDCn3mN5cY8HooHwE2ukiLb4p4G4ImmzvXyJt+tGwdw=
+github.com/nats-io/nkeys v0.4.12 h1:nssm7JKOG9/x4J8II47VWCL1Ds29avyiQDRn0ckMvDc=
+github.com/nats-io/nkeys v0.4.12/go.mod h1:MT59A1HYcjIcyQDJStTfaOY6vhy9XTUjOFo+SVsvpBg=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
 github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
 github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=

pkg/agent/loop.go

@@ -30,6 +30,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/routing"
 	"github.com/sipeed/picoclaw/pkg/skills"
 	"github.com/sipeed/picoclaw/pkg/state"
+	"github.com/sipeed/picoclaw/pkg/swarm"
 	"github.com/sipeed/picoclaw/pkg/tools"
 	"github.com/sipeed/picoclaw/pkg/utils"
 	"github.com/sipeed/picoclaw/pkg/voice"
@@ -46,6 +47,22 @@ type AgentLoop struct {
 	channelManager *channels.Manager
 	mediaStore     media.MediaStore
 	transcriber    voice.Transcriber
+
+	// Lifecycle context for proper shutdown propagation
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	// Swarm mode support
+	swarmEnabled        bool
+	swarmInitError      error // Set if swarm initialization fails
+	swarmDiscovery      swarm.Discovery
+	swarmHandoff        *swarm.HandoffCoordinator
+	swarmLoad           *swarm.LoadMonitor
+	swarmLeaderElection *swarm.LeaderElection
+	swarmSigner         *swarm.Signer // Message-layer signature verification for node-to-node messages
+
+	// Dynamic command registry (wired from channel manager)
+	commandRegistry *channels.CommandRegistry
 }
 
 // processOptions configures how a message is processed
@@ -84,7 +101,7 @@ func NewAgentLoop(
 		stateManager = state.NewManager(defaultAgent.Workspace)
 	}
 
-	return &AgentLoop{
+	al := &AgentLoop{
 		bus:         msgBus,
 		cfg:         cfg,
 		registry:    registry,
@@ -92,6 +109,13 @@ func NewAgentLoop(
 		summarizing: sync.Map{},
 		fallback:    fallbackChain,
 	}
+
+	// Initialize swarm mode if enabled
+	if cfg.Swarm.Enabled {
+		al.initSwarm()
+	}
+
+	return al
 }
 
 // registerSharedTools registers tools that are shared across all agents (web, message, spawn).
@@ -208,6 +232,10 @@ func registerSharedTools(
 }
 
 func (al *AgentLoop) Run(ctx context.Context) error {
+	// Store context for proper cancellation propagation
+	al.ctx, al.cancel = context.WithCancel(ctx)
+	defer al.cancel()
+
 	al.running.Store(true)
 
 	// Initialize MCP servers for all agents
@@ -350,6 +378,12 @@ func (al *AgentLoop) Run(ctx context.Context) error {
 
 func (al *AgentLoop) Stop() {
 	al.running.Store(false)
+	// Gracefully shutdown swarm mode components if enabled
+	if al.swarmEnabled {
+		if err := al.ShutdownSwarm(); err != nil {
+			logger.WarnCF("swarm", "Error during swarm shutdown", map[string]any{"error": err})
+		}
+	}
 }
 
 func (al *AgentLoop) RegisterTool(tool tools.Tool) {
@@ -362,6 +396,12 @@ func (al *AgentLoop) RegisterTool(tool tools.Tool) {
 
 func (al *AgentLoop) SetChannelManager(cm *channels.Manager) {
 	al.channelManager = cm
+	al.commandRegistry = cm.CommandRegistry()
+
+	// Wire up swarm commands
+	if al.swarmEnabled {
+		al.registerSwarmCommands()
+	}
 }
 
 // SetMediaStore injects a MediaStore for media lifecycle management.
@@ -545,6 +585,25 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 		return al.processSystemMessage(ctx, msg)
 	}
 
+	// Check for @node-id routing syntax
+	if al.swarmEnabled {
+		if targetNodeID, content := tools.ParseNodeMention(msg.Content); targetNodeID != "" {
+			logger.InfoCF("swarm", "Node mention detected", map[string]any{
+				"target":  targetNodeID,
+				"content": utils.Truncate(content, 50),
+			})
+			return al.handleNodeRouting(ctx, msg, targetNodeID, content)
+		}
+
+		// For non-mentioned messages in swarm mode, only leader processes
+		if al.swarmLeaderElection != nil && !al.swarmLeaderElection.IsLeader() {
+			logger.DebugCF("swarm", "Ignoring message (not leader)", map[string]any{
+				"content": utils.Truncate(msg.Content, 50),
+			})
+			return "", nil
+		}
+	}
+
 	// Check for commands
 	if response, handled := al.handleCommand(ctx, msg); handled {
 		return response, nil
@@ -588,6 +647,22 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 			"matched_by":  route.MatchedBy,
 		})
 
+	// Check if we should handoff this request to another node
+	if al.swarmEnabled && al.shouldHandoff(agent, processOptions{
+		SessionKey:  sessionKey,
+		Channel:     msg.Channel,
+		ChatID:      msg.ChatID,
+		UserMessage: msg.Content,
+	}) {
+		handoffResp, err := al.initiateSwarmHandoff(ctx, agent, sessionKey, msg)
+		if err == nil && handoffResp != nil && handoffResp.Accepted {
+			// Handoff was successful, return the response
+			return fmt.Sprintf("Your request has been handed off to node %s for processing.", handoffResp.NodeID), nil
+		}
+		// If handoff failed, continue processing locally
+		logger.WarnCF("swarm", "Handoff failed, processing locally", map[string]any{"error": err})
+	}
+
 	return al.runAgentLoop(ctx, agent, processOptions{
 		SessionKey:      sessionKey,
 		Channel:         msg.Channel,
@@ -671,6 +746,10 @@ func (al *AgentLoop) runAgentLoop(
 	agent *AgentInstance,
 	opts processOptions,
 ) (string, error) {
+	// Track active session for swarm load monitoring
+	al.IncrementSwarmSessions()
+	defer al.DecrementSwarmSessions()
+
 	// 0. Record last channel for heartbeat notifications (skip internal channels)
 	if opts.Channel != "" && opts.ChatID != "" {
 		// Don't record internal channels (cli, system, subagent)
@@ -1177,6 +1256,15 @@ func (al *AgentLoop) maybeSummarize(agent *AgentInstance, sessionKey, channel, c
 			go func() {
 				defer al.summarizing.Delete(summarizeKey)
 				logger.Debug("Memory threshold reached. Optimizing conversation history...")
+				if !constants.IsInternalChannel(channel) {
+					pubCtx, pubCancel := context.WithTimeout(context.Background(), 5*time.Second)
+					defer pubCancel()
+					al.bus.PublishOutbound(pubCtx, bus.OutboundMessage{
+						Channel: channel,
+						ChatID:  chatID,
+						Content: "Memory threshold reached. Optimizing conversation history...",
+					})
+				}
 				al.summarizeSession(agent, sessionKey)
 			}()
 		}
@@ -1543,6 +1631,19 @@ func (al *AgentLoop) handleCommand(ctx context.Context, msg bus.InboundMessage)
 		}
 	}
 
+	// Check dynamic command registry
+	if al.commandRegistry != nil {
+		cmdName := strings.TrimPrefix(parts[0], "/")
+		if entry, ok := al.commandRegistry.Get(cmdName); ok {
+			argsStr := strings.Join(args, " ")
+			response, err := entry.Handler(ctx, argsStr, msg)
+			if err != nil {
+				return fmt.Sprintf("Command error: %v", err), true
+			}
+			return response, true
+		}
+	}
+
 	return "", false
 }
 

pkg/agent/loop_swarm.go

@@ -0,0 +1,925 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package agent
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/sipeed/picoclaw/pkg/bus"
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/logger"
+	"github.com/sipeed/picoclaw/pkg/swarm"
+	"github.com/sipeed/picoclaw/pkg/tools"
+)
+
+// handleNodeRouting handles routing a message to a specific node in the swarm via NATS.
+func (al *AgentLoop) handleNodeRouting(
+	ctx context.Context,
+	msg bus.InboundMessage,
+	targetNodeID, content string,
+) (string, error) {
+	// Check if target is this node
+	if targetNodeID == al.swarmDiscovery.LocalNode().ID {
+		logger.InfoCF("swarm", "Target is this node, processing locally", map[string]any{"node_id": targetNodeID})
+		msg.Content = content
+		return al.processMessage(ctx, msg)
+	}
+
+	// Find target node
+	members := al.swarmDiscovery.Members()
+	var target *swarm.NodeWithState
+	for _, m := range members {
+		if m.Node.ID == targetNodeID {
+			target = m
+			break
+		}
+	}
+
+	if target == nil {
+		return fmt.Sprintf("Node '%s' not found in cluster. Use /nodes to see available nodes.", targetNodeID), nil
+	}
+
+	// Check if target is available
+	if target.State.Status != swarm.NodeStatusAlive {
+		return fmt.Sprintf("Node '%s' is not alive (status: %s)", targetNodeID, target.State.Status), nil
+	}
+
+	// Check if target is overloaded using configurable threshold with hysteresis
+	rejectThreshold := al.cfg.Swarm.LoadMonitor.RoutingRejectThreshold
+	if rejectThreshold == 0 {
+		rejectThreshold = swarm.DefaultRoutingRejectThreshold // Default to 0.9
+	}
+	if target.Node.LoadScore > rejectThreshold {
+		return fmt.Sprintf("Node '%s' is overloaded (load: %.0f%%, threshold: %.0f%%)",
+			targetNodeID, target.Node.LoadScore*100, rejectThreshold*100), nil
+	}
+
+	nc := al.swarmDiscovery.NATSConn()
+	if nc == nil {
+		return "Node-to-node communication not initialized (NATS not connected)", nil
+	}
+
+	// Send message via NATS to target node's message subject
+	subject := swarm.SubjectNodeMsg + "." + targetNodeID + ".msg"
+
+	payload := map[string]any{
+		"content":   content,
+		"channel":   msg.Channel,
+		"chat_id":   msg.ChatID,
+		"sender_id": msg.SenderID,
+		"from_node": al.swarmDiscovery.LocalNode().ID,
+	}
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Sprintf("Failed to marshal message: %v", err), nil
+	}
+
+	logger.InfoCF("swarm", "Sending message to remote node via NATS", map[string]any{
+		"target":  targetNodeID,
+		"subject": subject,
+		"load":    target.Node.LoadScore,
+	})
+
+	// Use NATS request-reply for synchronous response
+	reply, err := nc.RequestWithContext(ctx, subject, data)
+	if err != nil {
+		return fmt.Sprintf("Failed to send message to node '%s': %v", targetNodeID, err), nil
+	}
+
+	// Parse response
+	var response map[string]any
+	if err := json.Unmarshal(reply.Data, &response); err != nil {
+		return string(reply.Data), nil //nolint:nilerr // Fallback to raw response on parse failure
+	}
+
+	if errMsg, ok := response["error"].(string); ok && errMsg != "" {
+		return fmt.Sprintf("Node '%s' error: %s", targetNodeID, errMsg), nil
+	}
+
+	if resp, ok := response["response"].(string); ok {
+		return resp, nil
+	}
+
+	return string(reply.Data), nil
+}
+
+// initSwarm initializes the swarm mode components.
+func (al *AgentLoop) initSwarm() {
+	logger.InfoC("swarm", "Initializing swarm mode")
+
+	// Convert config and create discovery service directly (NATS-only)
+	swarmConfig := al.convertToSwarmConfig(al.cfg.Swarm)
+	discovery, err := swarm.NewDiscoveryService(swarmConfig)
+	if err != nil {
+		logger.ErrorCF(
+			"swarm",
+			"SWARM INIT FAILED: discovery service creation failed — swarm mode will be disabled",
+			map[string]any{"error": err.Error()},
+		)
+		al.swarmInitError = fmt.Errorf("discovery service creation failed: %w", err)
+		return
+	}
+	if err := discovery.Start(); err != nil {
+		logger.ErrorCF(
+			"swarm",
+			"SWARM INIT FAILED: discovery service start failed — swarm mode will be disabled",
+			map[string]any{"error": err.Error()},
+		)
+		al.swarmInitError = fmt.Errorf("discovery service start failed: %w", err)
+		return
+	}
+	al.swarmDiscovery = discovery
+
+	// Create handoff coordinator using config from convertToSwarmConfig (with default duration protection)
+	al.swarmHandoff = swarm.NewHandoffCoordinator(discovery, swarmConfig.Handoff)
+
+	// Configure crypto settings if provided
+	if al.cfg.Swarm.Handoff.SharedSecret != "" || al.cfg.Swarm.Handoff.EncryptionKey != "" {
+		cryptoCfg := swarm.CryptoConfig{
+			SharedSecret:      al.cfg.Swarm.Handoff.SharedSecret,
+			EncryptionKey:     al.cfg.Swarm.Handoff.EncryptionKey,
+			RequireAuth:       al.cfg.Swarm.Handoff.RequireAuth,
+			RequireEncryption: al.cfg.Swarm.Handoff.RequireEncryption,
+		}
+		if err := al.swarmHandoff.SetCryptoConfig(cryptoCfg); err != nil {
+			logger.ErrorCF(
+				"swarm",
+				"Failed to configure handoff crypto — handoff disabled",
+				map[string]any{"error": err.Error()},
+			)
+			al.swarmHandoff.Close()
+			al.swarmHandoff = nil
+		} else {
+			logger.InfoCF("swarm", "Handoff crypto configured", map[string]any{
+				"auth_enabled":       al.cfg.Swarm.Handoff.SharedSecret != "",
+				"encryption_enabled": al.cfg.Swarm.Handoff.EncryptionKey != "",
+			})
+		}
+	}
+
+	// Initialize signer for node-to-node message authentication
+	// Uses the same SharedSecret as handoff for consistency
+	if al.cfg.Swarm.Handoff.SharedSecret != "" {
+		al.swarmSigner = swarm.NewSigner(al.cfg.Swarm.Handoff.SharedSecret)
+		logger.InfoCF("swarm", "Node message signing enabled", map[string]any{
+			"require_auth": al.cfg.Swarm.Handoff.RequireAuth,
+		})
+	} else if al.cfg.Swarm.Handoff.RequireAuth {
+		logger.WarnCF(
+			"swarm",
+			"RequireAuth is set but no SharedSecret provided - node messages will not be signed or verified",
+			nil,
+		)
+	}
+
+	if al.swarmHandoff != nil {
+		if err := al.swarmHandoff.Start(); err != nil {
+			logger.ErrorCF("swarm", "Failed to start handoff coordinator", map[string]any{"error": err.Error()})
+		}
+	}
+
+	// Create and start load monitor using config from convertToSwarmConfig (with default duration protection)
+	al.swarmLoad = swarm.NewLoadMonitor(&swarmConfig.LoadMonitor)
+	if al.cfg.Swarm.LoadMonitor.Enabled {
+		al.swarmLoad.Start()
+		al.swarmLoad.OnThreshold(func(score float64) {
+			discovery.UpdateLoad(score)
+		})
+	}
+
+	// Wire load monitor to discovery service for detailed status publishing
+	discovery.SetLoadMonitor(al.swarmLoad)
+
+	al.swarmEnabled = true
+
+	// Initialize leader election if enabled
+	if al.cfg.Swarm.LeaderElection.Enabled {
+		al.initSwarmLeaderElection(discovery)
+	}
+
+	// Set up NATS subscription for incoming directed node messages
+	al.setupNodeMessageSubscription(discovery)
+
+	// Register swarm tools
+	al.registerSwarmTools(discovery)
+
+	// Subscribe to node events for logging
+	al.subscribeSwarmEvents(discovery)
+
+	logger.InfoCF("swarm", "Swarm mode initialized", map[string]any{
+		"node_id":  discovery.LocalNode().ID,
+		"nats_url": al.cfg.Swarm.Discovery.NATSURL,
+		"handoff":  al.cfg.Swarm.Handoff.Enabled,
+	})
+}
+
+// setupNodeMessageSubscription subscribes to incoming directed messages via NATS.
+func (al *AgentLoop) setupNodeMessageSubscription(discovery swarm.Discovery) {
+	nc := discovery.NATSConn()
+	if nc == nil {
+		logger.WarnC("swarm", "NATS connection not available, node message subscription skipped")
+		return
+	}
+
+	localNodeID := discovery.LocalNode().ID
+	subject := swarm.SubjectNodeMsg + "." + localNodeID + ".msg"
+
+	_, err := nc.Subscribe(subject, func(msg *nats.Msg) {
+		al.handleIncomingNATSNodeMessage(msg)
+	})
+	if err != nil {
+		logger.ErrorCF("swarm", "Failed to subscribe to node message subject", map[string]any{
+			"subject": subject,
+			"error":   err.Error(),
+		})
+		return
+	}
+
+	logger.InfoCF("swarm", "Subscribed to node messages", map[string]any{"subject": subject})
+}
+
+// handleIncomingNATSNodeMessage handles a message received from another node via NATS.
+func (al *AgentLoop) handleIncomingNATSNodeMessage(msg *nats.Msg) {
+	var payload map[string]any
+	if err := json.Unmarshal(msg.Data, &payload); err != nil {
+		logger.ErrorCF("swarm", "Failed to decode incoming node message", map[string]any{"error": err.Error()})
+		al.sendNodeReply(msg, "invalid message format", nil)
+		return
+	}
+
+	// Verify sender is a known swarm member (routing authorization)
+	fromNode, _ := payload["from_node"].(string)
+	if fromNode != "" && al.swarmDiscovery != nil {
+		members := al.swarmDiscovery.Members()
+		isKnownMember := false
+		for _, m := range members {
+			if m.Node.ID == fromNode {
+				isKnownMember = true
+				break
+			}
+		}
+		if !isKnownMember {
+			logger.WarnCF("swarm", "Rejected node message from unknown member", map[string]any{
+				"from_node":     fromNode,
+				"known_members": len(members),
+			})
+			al.sendNodeReply(msg, "unknown node", nil)
+			return
+		}
+	}
+
+	// Verify message signature if signer is configured
+	signature, hasSignature := payload["signature"].(string)
+	if hasSignature && al.swarmSigner != nil {
+		// Create a copy of payload without signature for verification
+		payloadToVerify := make(map[string]any)
+		for k, v := range payload {
+			if k != "signature" {
+				payloadToVerify[k] = v
+			}
+		}
+		if !al.swarmSigner.Verify(payloadToVerify, signature) {
+			logger.WarnCF("swarm", "Rejected node message with invalid signature", map[string]any{
+				"from_node": fromNode,
+			})
+			al.sendNodeReply(msg, "invalid signature", nil)
+			return
+		}
+	} else if al.cfg.Swarm.Handoff.RequireAuth && al.swarmSigner == nil {
+		// RequireAuth is enabled but no signer configured - reject for safety
+		logger.WarnCF(
+			"swarm",
+			"Rejected node message - RequireAuth enabled but no signature verification configured",
+			map[string]any{
+				"from_node": fromNode,
+			},
+		)
+		al.sendNodeReply(msg, "signature required but not configured", nil)
+		return
+	} else if al.cfg.Swarm.Handoff.RequireAuth && !hasSignature {
+		// RequireAuth is enabled but message has no signature
+		logger.WarnCF("swarm", "Rejected unsigned node message - RequireAuth enabled", map[string]any{
+			"from_node": fromNode,
+		})
+		al.sendNodeReply(msg, "signature required", nil)
+		return
+	}
+
+	// Check for action-based request (lightweight, no LLM processing)
+	action, hasAction := payload["action"].(string)
+	if hasAction {
+		al.handleNodeActionRequest(msg, action, payload, fromNode)
+		return
+	}
+
+	// Content-based message (full LLM processing)
+	content, _ := payload["content"].(string)
+	channel, _ := payload["channel"].(string)
+	chatID, _ := payload["chat_id"].(string)
+	senderID, _ := payload["sender_id"].(string)
+
+	// Require content for message processing
+	if content == "" {
+		al.sendNodeReply(msg, "empty content", nil)
+		return
+	}
+
+	logger.InfoCF("swarm", "Processing incoming node message", map[string]any{
+		"from":    fromNode,
+		"content": content[:min(50, len(content))],
+	})
+
+	// Create an inbound message and process with a timeout context
+	inboundMsg := bus.InboundMessage{
+		Content:  content,
+		Channel:  channel,
+		ChatID:   chatID,
+		SenderID: senderID,
+	}
+
+	// Use parent context from AgentLoop for proper cancellation propagation
+	// If al.ctx is not set (e.g., during initialization), fall back to background context
+	const nodeMessageTimeout = 120 * time.Second
+	parentCtx := al.ctx
+	if parentCtx == nil {
+		parentCtx = context.Background()
+	}
+	ctx, cancel := context.WithTimeout(parentCtx, nodeMessageTimeout)
+	defer cancel()
+
+	response, err := al.processMessage(ctx, inboundMsg)
+
+	// Send reply if request-reply pattern
+	if msg.Reply != "" {
+		var respData []byte
+		if err != nil {
+			respData, _ = json.Marshal(map[string]any{"error": err.Error()})
+		} else {
+			respData, _ = json.Marshal(map[string]any{"response": response})
+		}
+		msg.Respond(respData)
+	}
+}
+
+// handleNodeActionRequest handles lightweight action requests (status, ping, health, etc.)
+// These actions bypass LLM processing and return structured responses directly.
+func (al *AgentLoop) handleNodeActionRequest(msg *nats.Msg, action string, payload map[string]any, fromNode string) {
+	logger.InfoCF("swarm", "Processing node action request", map[string]any{
+		"from":   fromNode,
+		"action": action,
+	})
+
+	var response any
+	var err error
+
+	switch action {
+	case swarm.NodeActionPing:
+		response = map[string]any{
+			"status":  "pong",
+			"node_id": al.swarmDiscovery.LocalNode().ID,
+		}
+
+	case swarm.NodeActionStatus:
+		response = al.GetSwarmStatus()
+
+	case swarm.NodeActionHealth:
+		response = map[string]any{
+			"status":  "healthy",
+			"node_id": al.swarmDiscovery.LocalNode().ID,
+		}
+
+	case swarm.NodeActionLeader:
+		if al.swarmLeaderElection != nil {
+			response = map[string]any{
+				"leader_id": al.swarmLeaderElection.GetLeader(),
+				"is_leader": al.swarmLeaderElection.IsLeader(),
+			}
+		} else {
+			response = map[string]any{
+				"leader_id": nil,
+				"message":   "leader election not enabled",
+			}
+		}
+
+	case swarm.NodeActionMetrics:
+		response = al.GetSwarmStatus()
+
+	default:
+		err = fmt.Errorf("unknown action: %s", action)
+	}
+
+	// Send reply
+	if msg.Reply != "" {
+		respData, _ := json.Marshal(map[string]any{
+			"response": response,
+			"error":    err,
+		})
+		msg.Respond(respData)
+	}
+}
+
+// sendNodeReply sends a standardized error reply to a node message.
+func (al *AgentLoop) sendNodeReply(msg *nats.Msg, errMsg string, payload map[string]any) {
+	if msg.Reply == "" {
+		return
+	}
+	reply := map[string]any{"error": errMsg}
+	if payload != nil {
+		for k, v := range payload {
+			reply[k] = v
+		}
+	}
+	respData, _ := json.Marshal(reply)
+	msg.Respond(respData)
+}
+
+// initSwarmLeaderElection initializes the leader election module using NATS KV CAS lock.
+func (al *AgentLoop) initSwarmLeaderElection(discovery swarm.Discovery) {
+	js := discovery.JetStream()
+	if js == nil {
+		logger.WarnCF("swarm", "JetStream not available, leader election disabled", nil)
+		return
+	}
+
+	// Convert config
+	leaderElectionConfig := swarm.LeaderElectionConfig{
+		Enabled: al.cfg.Swarm.LeaderElection.Enabled,
+		LockTTL: swarm.Duration{
+			Duration: time.Duration(al.cfg.Swarm.LeaderElection.LockTTL) * time.Second,
+		},
+		RenewalInterval: swarm.Duration{
+			Duration: time.Duration(al.cfg.Swarm.LeaderElection.RenewalInterval) * time.Second,
+		},
+	}
+
+	// Create leader election instance with JetStream
+	buckets := discovery.Buckets()
+	if buckets == nil || buckets.Leader == nil {
+		logger.WarnCF("swarm", "Leader bucket not available, leader election disabled", nil)
+		return
+	}
+	leaderElection, err := swarm.NewLeaderElection(
+		discovery.LocalNode().ID,
+		buckets.Leader,
+		leaderElectionConfig,
+	)
+	if err != nil {
+		logger.ErrorCF("swarm", "Failed to create leader election", map[string]any{"error": err.Error()})
+		return
+	}
+
+	// Start leader election
+	if err := leaderElection.Start(); err != nil {
+		logger.ErrorCF("swarm", "Failed to start leader election", map[string]any{"error": err.Error()})
+		return
+	}
+	al.swarmLeaderElection = leaderElection
+
+	logger.InfoCF("swarm", "Leader election initialized (KV CAS lock)", map[string]any{
+		"node_id": discovery.LocalNode().ID,
+		"enabled": al.cfg.Swarm.LeaderElection.Enabled,
+	})
+}
+
+// sendMessageToNode sends a message to a target node via NATS.
+func (al *AgentLoop) sendMessageToNode(
+	ctx context.Context,
+	targetNodeID, content, channel, chatID, senderID string,
+) (string, error) {
+	nc := al.swarmDiscovery.NATSConn()
+	if nc == nil {
+		return "", fmt.Errorf("NATS connection not available")
+	}
+
+	subject := swarm.SubjectNodeMsg + "." + targetNodeID + ".msg"
+
+	payload := map[string]any{
+		"content":   content,
+		"channel":   channel,
+		"chat_id":   chatID,
+		"sender_id": senderID,
+		"from_node": al.swarmDiscovery.LocalNode().ID,
+		"timestamp": time.Now().UnixNano(),
+	}
+
+	// Add signature if signer is configured
+	if al.swarmSigner != nil {
+		signature, err := al.swarmSigner.Sign(payload)
+		if err != nil {
+			return "", fmt.Errorf("failed to sign message: %w", err)
+		}
+		payload["signature"] = signature
+	}
+
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal message: %w", err)
+	}
+
+	reply, err := nc.RequestWithContext(ctx, subject, data)
+	if err != nil {
+		return "", fmt.Errorf("failed to send message to node %s: %w", targetNodeID, err)
+	}
+
+	var response map[string]any
+	if err := json.Unmarshal(reply.Data, &response); err != nil {
+		return string(reply.Data), nil //nolint:nilerr // Fallback to raw response on parse failure
+	}
+
+	if errMsg, ok := response["error"].(string); ok && errMsg != "" {
+		return "", fmt.Errorf("node %s error: %s", targetNodeID, errMsg)
+	}
+
+	if resp, ok := response["response"].(string); ok {
+		return resp, nil
+	}
+
+	return string(reply.Data), nil
+}
+
+// sendActionToNode sends an action-based request to a target node via NATS.
+// Used for fast operations like 'status' that don't require LLM processing.
+func (al *AgentLoop) sendActionToNode(
+	ctx context.Context,
+	targetNodeID, action string,
+) (string, error) {
+	nc := al.swarmDiscovery.NATSConn()
+	if nc == nil {
+		return "", fmt.Errorf("NATS connection not available")
+	}
+
+	subject := swarm.SubjectNodeMsg + "." + targetNodeID + ".msg"
+
+	payload := map[string]any{
+		"action":    action,
+		"from_node": al.swarmDiscovery.LocalNode().ID,
+		"timestamp": time.Now().UnixNano(),
+	}
+
+	// Add signature if signer is configured
+	if al.swarmSigner != nil {
+		signature, err := al.swarmSigner.Sign(payload)
+		if err != nil {
+			return "", fmt.Errorf("failed to sign action: %w", err)
+		}
+		payload["signature"] = signature
+	}
+
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal action: %w", err)
+	}
+
+	reply, err := nc.RequestWithContext(ctx, subject, data)
+	if err != nil {
+		return "", fmt.Errorf("failed to send action to node %s: %w", targetNodeID, err)
+	}
+
+	var response map[string]any
+	if err := json.Unmarshal(reply.Data, &response); err != nil {
+		return string(reply.Data), nil //nolint:nilerr // Fallback to raw response on parse failure
+	}
+
+	if errMsg, ok := response["error"].(string); ok && errMsg != "" {
+		return "", fmt.Errorf("node error: %s", errMsg)
+	}
+
+	if resp, ok := response["response"].(string); ok {
+		return resp, nil
+	}
+
+	return string(reply.Data), nil
+}
+
+// registerSwarmTools registers swarm-related tools (handoff, routing).
+func (al *AgentLoop) registerSwarmTools(discovery swarm.Discovery) {
+	localNodeID := discovery.LocalNode().ID
+
+	swarmTool := tools.NewSwarmTool(discovery, al.swarmLoad, localNodeID)
+	swarmTool.SetSendMessageFn(al.sendMessageToNode)
+	al.RegisterTool(swarmTool)
+
+	nodesTool := tools.NewSwarmNodesTool(discovery, al.swarmLoad, localNodeID)
+	al.RegisterTool(nodesTool)
+
+	routeTool := tools.NewSwarmRouteTool(discovery, al.swarmHandoff, localNodeID)
+	routeTool.SetSendMessageFn(al.sendMessageToNode)
+	routeTool.SetSendActionFn(al.sendActionToNode)
+	al.RegisterTool(routeTool)
+
+	// Register batch query tool for parallel node queries
+	batchTool := tools.NewSwarmBatchTool(discovery, localNodeID)
+	batchTool.SetSendActionFn(al.sendActionToNode)
+	al.RegisterTool(batchTool)
+}
+
+// subscribeSwarmEvents subscribes to node join/leave events.
+func (al *AgentLoop) subscribeSwarmEvents(discovery swarm.Discovery) {
+	_ = discovery.Subscribe(func(event *swarm.NodeEvent) {
+		switch event.Event {
+		case swarm.EventJoin:
+			logger.InfoCF("swarm", "Node joined", map[string]any{"node_id": event.Node.ID})
+		case swarm.EventLeave:
+			logger.InfoCF("swarm", "Node left", map[string]any{"node_id": event.Node.ID})
+		}
+	})
+}
+
+// registerSwarmCommands registers swarm slash commands on the channel command registry.
+func (al *AgentLoop) registerSwarmCommands() {
+	if al.commandRegistry == nil {
+		return
+	}
+
+	// If swarm init failed, register a /nodes command that shows the error.
+	if al.swarmDiscovery == nil {
+		if al.swarmInitError != nil {
+			al.commandRegistry.Register("nodes", "List swarm cluster nodes", func(
+				ctx context.Context, args string, msg bus.InboundMessage,
+			) (string, error) {
+				return fmt.Sprintf("Swarm mode failed to initialize: %s", al.swarmInitError), nil
+			})
+		}
+		return
+	}
+
+	localNodeID := al.swarmDiscovery.LocalNode().ID
+
+	al.commandRegistry.Register("nodes", "List swarm cluster nodes", func(
+		ctx context.Context, args string, msg bus.InboundMessage,
+	) (string, error) {
+		verbose := strings.Contains(args, "verbose") || strings.Contains(args, "-v")
+		return tools.FormatClusterStatus(al.swarmDiscovery, al.swarmLoad, localNodeID, verbose), nil
+	})
+}
+
+// convertToSwarmConfig converts the config.SwarmConfig to swarm.Config.
+func (al *AgentLoop) convertToSwarmConfig(cfg config.SwarmConfig) *swarm.Config {
+	applyDurationDefault := func(val int, defaultVal time.Duration) time.Duration {
+		if val <= 0 {
+			return defaultVal
+		}
+		return time.Duration(val) * time.Second
+	}
+
+	return &swarm.Config{
+		Enabled: cfg.Enabled,
+		NodeID:  cfg.NodeID,
+		Discovery: swarm.DiscoveryConfig{
+			NATSURL:       cfg.Discovery.NATSURL,
+			NATSCredsFile: cfg.Discovery.NATSCredsFile,
+			NATSTLSCert:   cfg.Discovery.NATSTLSCert,
+			NATSTLSKey:    cfg.Discovery.NATSTLSKey,
+			NATSTLSCACert: cfg.Discovery.NATSTLSCACert,
+			HeartbeatInterval: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Discovery.HeartbeatInterval, swarm.DefaultHeartbeatInterval),
+			},
+			MemberTTL: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Discovery.MemberTTL, swarm.DefaultMemberTTL),
+			},
+			SubjectPrefix: cfg.Discovery.SubjectPrefix,
+			NodeTimeout: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Discovery.NodeTimeout, swarm.DefaultNodeTimeout),
+			},
+			DeadNodeTimeout: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Discovery.DeadNodeTimeout, swarm.DefaultDeadNodeTimeout),
+			},
+		},
+		Handoff: swarm.HandoffConfig{
+			Enabled:       cfg.Handoff.Enabled,
+			LoadThreshold: cfg.Handoff.LoadThreshold,
+			Timeout: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Handoff.Timeout, swarm.DefaultHandoffTimeout),
+			},
+			MaxRetries: cfg.Handoff.MaxRetries,
+			RetryDelay: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Handoff.RetryDelay, swarm.DefaultHandoffRetryDelay),
+			},
+			RequestTimeout: swarm.Duration{
+				Duration: applyDurationDefault(cfg.Handoff.RequestTimeout, swarm.DefaultHandoffRequestTimeout),
+			},
+		},
+		LoadMonitor: swarm.LoadMonitorConfig{
+			Enabled: cfg.LoadMonitor.Enabled,
+			Interval: swarm.Duration{
+				Duration: applyDurationDefault(cfg.LoadMonitor.Interval, swarm.DefaultLoadSampleInterval),
+			},
+			SampleSize:    cfg.LoadMonitor.SampleSize,
+			CPUWeight:     cfg.LoadMonitor.CPUWeight,
+			MemoryWeight:  cfg.LoadMonitor.MemoryWeight,
+			SessionWeight: cfg.LoadMonitor.SessionWeight,
+		},
+		LeaderElection: swarm.LeaderElectionConfig{
+			Enabled: cfg.LeaderElection.Enabled,
+			LockTTL: swarm.Duration{
+				Duration: applyDurationDefault(cfg.LeaderElection.LockTTL, swarm.DefaultLeaderLockTTL),
+			},
+			RenewalInterval: swarm.Duration{
+				Duration: applyDurationDefault(cfg.LeaderElection.RenewalInterval, swarm.DefaultLeaderRenewalInterval),
+			},
+		},
+	}
+}
+
+// shouldHandoff determines if the current request should be handed off to another node.
+func (al *AgentLoop) shouldHandoff(agent *AgentInstance, opts processOptions) bool {
+	if !al.swarmEnabled || al.swarmHandoff == nil {
+		return false
+	}
+
+	if al.swarmLoad != nil && al.swarmLoad.ShouldOffload() {
+		logger.InfoCF("swarm", "Load threshold exceeded, considering handoff", map[string]any{
+			"load_score": al.swarmLoad.GetCurrentLoad().Score,
+		})
+		return true
+	}
+
+	return false
+}
+
+// UpdateSwarmLoad updates the current load score reported to the swarm.
+func (al *AgentLoop) UpdateSwarmLoad(sessionCount int) {
+	if al.swarmLoad != nil {
+		al.swarmLoad.SetSessionCount(sessionCount)
+	}
+}
+
+// IncrementSwarmSessions increments the active session count.
+func (al *AgentLoop) IncrementSwarmSessions() {
+	if al.swarmLoad != nil {
+		al.swarmLoad.IncrementSessions()
+	}
+}
+
+// DecrementSwarmSessions decrements the active session count.
+func (al *AgentLoop) DecrementSwarmSessions() {
+	if al.swarmLoad != nil {
+		al.swarmLoad.DecrementSessions()
+	}
+}
+
+// GetSwarmStatus returns the current swarm status with metrics and component health.
+func (al *AgentLoop) GetSwarmStatus() map[string]any {
+	if !al.swarmEnabled {
+		if al.swarmInitError != nil {
+			return map[string]any{
+				"enabled": false,
+				"error":   al.swarmInitError.Error(),
+			}
+		}
+		return map[string]any{"enabled": false}
+	}
+
+	status := map[string]any{
+		"enabled": true,
+		"node_id": al.swarmDiscovery.LocalNode().ID,
+		"handoff": al.cfg.Swarm.Handoff.Enabled,
+	}
+
+	// Component health status
+	health := map[string]bool{
+		"discovery":       al.swarmDiscovery != nil,
+		"handoff":         al.swarmHandoff != nil,
+		"load_monitor":    al.swarmLoad != nil,
+		"leader_election": al.swarmLeaderElection != nil,
+	}
+	if al.swarmHandoff != nil {
+		for k, v := range al.swarmHandoff.ComponentHealth() {
+			health[k] = v
+		}
+		circuitBreakerStatus := al.swarmHandoff.GetCircuitBreakerStatus()
+		if len(circuitBreakerStatus) > 0 {
+			status["circuit_breaker"] = circuitBreakerStatus
+		}
+	}
+	status["components"] = health
+
+	if al.swarmLoad != nil {
+		metrics := al.swarmLoad.GetCurrentLoad()
+		status["load"] = map[string]any{
+			"score":           metrics.Score,
+			"cpu_usage":       metrics.CPUUsage,
+			"memory_usage":    metrics.MemoryUsage,
+			"active_sessions": metrics.ActiveSessions,
+			"goroutines":      metrics.Goroutines,
+			"trend":           al.swarmLoad.GetTrend(),
+		}
+	}
+
+	if al.swarmDiscovery != nil {
+		members := al.swarmDiscovery.Members()
+		status["members"] = len(members)
+	}
+
+	if al.swarmHandoff != nil {
+		status["handoff_metrics"] = al.swarmHandoff.GetMetrics().Snapshot()
+	}
+
+	return status
+}
+
+// ShutdownSwarm gracefully shuts down the swarm components.
+func (al *AgentLoop) ShutdownSwarm() error {
+	if !al.swarmEnabled {
+		return nil
+	}
+
+	var errs []string
+
+	if al.swarmLoad != nil {
+		al.swarmLoad.Stop()
+	}
+
+	if al.swarmLeaderElection != nil {
+		al.swarmLeaderElection.Stop()
+	}
+
+	if al.swarmHandoff != nil {
+		if err := al.swarmHandoff.Close(); err != nil {
+			errs = append(errs, fmt.Sprintf("handoff: %v", err))
+		}
+	}
+
+	if al.swarmDiscovery != nil {
+		if err := al.swarmDiscovery.Stop(); err != nil {
+			errs = append(errs, fmt.Sprintf("discovery: %v", err))
+		}
+	}
+
+	al.swarmEnabled = false
+
+	if len(errs) > 0 {
+		return fmt.Errorf("swarm shutdown errors: %s", strings.Join(errs, ", "))
+	}
+	return nil
+}
+
+// initiateSwarmHandoff initiates a handoff to another node.
+func (al *AgentLoop) initiateSwarmHandoff(
+	ctx context.Context,
+	agent *AgentInstance,
+	sessionKey string,
+	msg bus.InboundMessage,
+) (*swarm.HandoffResponse, error) {
+	if al.swarmHandoff == nil {
+		return nil, swarm.ErrDiscoveryDisabled
+	}
+
+	// Build session history for handoff
+	sessionMessages := make([]swarm.SessionMessage, 0)
+	history := agent.Sessions.GetHistory(sessionKey)
+
+	for _, m := range history {
+		if m.Role == "user" || m.Role == "assistant" {
+			sessionMessages = append(sessionMessages, swarm.SessionMessage{
+				Role:    m.Role,
+				Content: m.Content,
+			})
+		}
+	}
+
+	// Create handoff request
+	req := &swarm.HandoffRequest{
+		Reason:          swarm.ReasonOverloaded,
+		SessionKey:      sessionKey,
+		SessionMessages: sessionMessages,
+		Context: map[string]any{
+			"channel":  msg.Channel,
+			"chat_id":  msg.ChatID,
+			"sender":   msg.SenderID,
+			"agent_id": agent.ID,
+		},
+		Metadata: map[string]string{
+			"original_channel": msg.Channel,
+			"original_chat_id": msg.ChatID,
+		},
+	}
+
+	logger.InfoCF("swarm", "Initiating handoff", map[string]any{
+		"session_key": sessionKey,
+		"reason":      req.Reason,
+		"history_len": len(sessionMessages),
+	})
+
+	resp, err := al.swarmHandoff.InitiateHandoff(ctx, req)
+
+	if resp != nil {
+		logger.InfoCF("swarm", "Handoff response received", map[string]any{
+			"accepted": resp.Accepted,
+			"node_id":  resp.NodeID,
+			"state":    resp.State,
+		})
+	}
+
+	return resp, err
+}

pkg/channels/commands.go

@@ -0,0 +1,77 @@
+package channels
+
+import (
+	"context"
+	"sort"
+	"sync"
+
+	"github.com/sipeed/picoclaw/pkg/bus"
+)
+
+// CommandHandler processes a slash command and returns a text response.
+// args contains everything after the command name (e.g. for "/nodes verbose", args = "verbose").
+// msg provides the full inbound message context (channel, sender, chat, etc.).
+type CommandHandler func(ctx context.Context, args string, msg bus.InboundMessage) (string, error)
+
+// CommandEntry holds a registered command.
+type CommandEntry struct {
+	Name        string         // command name without leading slash, e.g. "nodes"
+	Description string         // human-readable description, e.g. "List swarm cluster nodes"
+	Handler     CommandHandler // function to execute
+}
+
+// CommandRegistry is a thread-safe registry of slash commands.
+// External modules register commands here; the agent loop checks it when
+// processing inbound messages that start with "/".
+type CommandRegistry struct {
+	mu       sync.RWMutex
+	commands map[string]*CommandEntry
+}
+
+// NewCommandRegistry creates an empty command registry.
+func NewCommandRegistry() *CommandRegistry {
+	return &CommandRegistry{
+		commands: make(map[string]*CommandEntry),
+	}
+}
+
+// Register adds or replaces a command in the registry.
+// name should NOT include the leading slash.
+func (r *CommandRegistry) Register(name, description string, handler CommandHandler) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.commands[name] = &CommandEntry{
+		Name:        name,
+		Description: description,
+		Handler:     handler,
+	}
+}
+
+// Get looks up a command by name. Returns nil, false if not found.
+func (r *CommandRegistry) Get(name string) (*CommandEntry, bool) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	entry, ok := r.commands[name]
+	return entry, ok
+}
+
+// List returns all registered commands sorted by name.
+func (r *CommandRegistry) List() []*CommandEntry {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	entries := make([]*CommandEntry, 0, len(r.commands))
+	for _, e := range r.commands {
+		entries = append(entries, e)
+	}
+	sort.Slice(entries, func(i, j int) bool {
+		return entries[i].Name < entries[j].Name
+	})
+	return entries
+}
+
+// Remove unregisters a command by name. No-op if not found.
+func (r *CommandRegistry) Remove(name string) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	delete(r.commands, name)
+}

pkg/channels/manager.go

@@ -79,12 +79,13 @@ type Manager struct {
 	bus           *bus.MessageBus
 	config        *config.Config
 	mediaStore    media.MediaStore
+	commands      *CommandRegistry
 	dispatchTask  *asyncTask
 	mux           *http.ServeMux
 	httpServer    *http.Server
 	mu            sync.RWMutex
-	placeholders  sync.Map // "channel:chatID" → placeholderID (string)
+	placeholders  sync.Map // "channel:chatID" → placeholderEntry
-	typingStops   sync.Map // "channel:chatID" → func()
+	typingStops   sync.Map // "channel:chatID" → typingEntry
 	reactionUndos sync.Map // "channel:chatID" → reactionEntry
 }
 
@@ -154,6 +155,7 @@ func NewManager(cfg *config.Config, messageBus *bus.MessageBus, store media.Medi
 		bus:        messageBus,
 		config:     cfg,
 		mediaStore: store,
+		commands:   NewCommandRegistry(),
 	}
 
 	if err := m.initChannels(); err != nil {
@@ -786,6 +788,12 @@ func (m *Manager) RegisterChannel(name string, channel Channel) {
 	m.channels[name] = channel
 }
 
+// CommandRegistry returns the shared command registry.
+// External modules use this to register slash commands that work across all channels.
+func (m *Manager) CommandRegistry() *CommandRegistry {
+	return m.commands
+}
+
 func (m *Manager) UnregisterChannel(name string) {
 	m.mu.Lock()
 	defer m.mu.Unlock()

pkg/channels/pico/pico.go

@@ -56,6 +56,8 @@ type PicoChannel struct {
 	connCount          atomic.Int32
 	ctx                context.Context
 	cancel             context.CancelFunc
+	nodeRequestHandler func(payload map[string]any) (map[string]any, error)
+	nodeValidator      func(sourceNodeID string) bool // validates source is a known swarm member
 }
 
 // NewPicoChannel creates a new Pico Protocol channel.
@@ -403,6 +405,9 @@ func (c *PicoChannel) handleMessage(pc *picoConn, msg PicoMessage) {
 	case TypeMessageSend:
 		c.handleMessageSend(pc, msg)
 
+	case TypeNodeRequest:
+		c.handleNodeRequest(pc, msg)
+
 	default:
 		errMsg := newError("unknown_type", fmt.Sprintf("unknown message type: %s", msg.Type))
 		pc.writeJSON(errMsg)
@@ -452,6 +457,119 @@ func (c *PicoChannel) handleMessageSend(pc *picoConn, msg PicoMessage) {
 	c.HandleMessage(c.ctx, peer, msg.ID, senderID, chatID, content, nil, metadata, sender)
 }
 
+// SetNodeRequestHandler sets the handler for incoming inter-node request messages.
+// The handler receives the full payload map and returns a reply payload map.
+func (c *PicoChannel) SetNodeRequestHandler(handler func(payload map[string]any) (map[string]any, error)) {
+	c.nodeRequestHandler = handler
+}
+
+// SetNodeValidator sets a function that validates whether a source_node_id
+// is a known, alive member of the swarm cluster. This prevents arbitrary
+// WebSocket clients from issuing node.request messages even if they hold
+// a valid Pico token.
+func (c *PicoChannel) SetNodeValidator(validator func(sourceNodeID string) bool) {
+	c.nodeValidator = validator
+}
+
+// handleNodeRequest processes an incoming node.request message from a swarm peer.
+//
+// Security model:
+//   - The WebSocket connection is already authenticated via Pico token.
+//   - If a nodeValidator is set, source_node_id MUST be a known alive swarm member.
+//     This prevents non-swarm WS clients from reaching inter-node control plane.
+//   - For production, also configure NATS-level ACLs as the primary trust boundary;
+//     this Pico path is a secondary/legacy channel.
+func (c *PicoChannel) handleNodeRequest(pc *picoConn, msg PicoMessage) {
+	requestID, _ := msg.Payload["request_id"].(string)
+	sourceNodeID, _ := msg.Payload["source_node_id"].(string)
+	action, _ := msg.Payload["action"].(string)
+
+	logger.InfoCF("pico", "Received node request", map[string]any{
+		"request_id":     requestID,
+		"source_node_id": sourceNodeID,
+		"action":         action,
+	})
+
+	// Validate source node identity against swarm membership.
+	if c.nodeValidator != nil && !c.nodeValidator(sourceNodeID) {
+		logger.WarnCF("pico", "Rejected node request from unknown/dead node", map[string]any{
+			"request_id":     requestID,
+			"source_node_id": sourceNodeID,
+		})
+		reply := newMessage(TypeNodeReply, map[string]any{
+			"request_id": requestID,
+			"error":      "source node not recognized as a cluster member",
+		})
+		reply.ID = msg.ID
+		_ = pc.writeJSON(reply)
+		return
+	}
+
+	var replyPayload map[string]any
+
+	if c.nodeRequestHandler == nil {
+		replyPayload = map[string]any{
+			"request_id": requestID,
+			"error":      "no node request handler registered",
+		}
+	} else {
+		// Start watchdog goroutine to send processing heartbeats
+		stopHeartbeat := make(chan struct{})
+		go c.watchDog(pc, msg.ID, requestID, stopHeartbeat)
+
+		// Call the handler and stop heartbeat when done
+		var err error
+		replyPayload, err = c.nodeRequestHandler(msg.Payload)
+		close(stopHeartbeat)
+
+		if err != nil {
+			replyPayload = map[string]any{
+				"request_id": requestID,
+				"error":      err.Error(),
+			}
+		}
+		// Ensure request_id is always in the reply
+		if replyPayload != nil {
+			replyPayload["request_id"] = requestID
+		}
+	}
+
+	reply := newMessage(TypeNodeReply, replyPayload)
+	reply.ID = msg.ID
+	if err := pc.writeJSON(reply); err != nil {
+		logger.ErrorCF("pico", "Failed to send node reply", map[string]any{
+			"error":      err.Error(),
+			"request_id": requestID,
+		})
+	}
+}
+
+// watchDog sends periodic processing heartbeats to keep the connection alive
+// while a long-running node request is being handled. It stops when the
+// stopHeartbeat channel is closed.
+func (c *PicoChannel) watchDog(pc *picoConn, msgID, requestID string, stop <-chan struct{}) {
+	ticker := time.NewTicker(nodeHeartbeatInterval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-stop:
+			return
+		case <-ticker.C:
+			heartbeat := newMessage(TypeNodeProcessing, map[string]any{
+				"request_id": requestID,
+			})
+			heartbeat.ID = msgID
+			if err := pc.writeJSON(heartbeat); err != nil {
+				logger.DebugCF("pico", "Failed to send processing heartbeat", map[string]any{
+					"error":      err.Error(),
+					"request_id": requestID,
+				})
+				// Don't return - keep trying until stop is closed
+			}
+		}
+	}
+}
+
 // truncate truncates a string to maxLen runes.
 func truncate(s string, maxLen int) string {
 	runes := []rune(s)

pkg/channels/pico/protocol.go

@@ -1,46 +1,59 @@
+// Package pico provides the Pico Protocol WebSocket channel implementation.
+// This file contains the local PicoMessage type wrapper for compatibility with
+// the canonical protocol definitions in pkg/pico/protocol.
 package pico
 
-import "time"
+import (
+	"time"
 
-// Protocol message types.
+	picoproto "github.com/sipeed/picoclaw/pkg/pico/protocol"
-const (
-	// TypeMessageSend is sent from client to server.
-	TypeMessageSend = "message.send"
-	TypeMediaSend   = "media.send"
-	TypePing        = "ping"
-
-	// TypeMessageCreate is sent from server to client.
-	TypeMessageCreate = "message.create"
-	TypeMessageUpdate = "message.update"
-	TypeMediaCreate   = "media.create"
-	TypeTypingStart   = "typing.start"
-	TypeTypingStop    = "typing.stop"
-	TypeError         = "error"
-	TypePong          = "pong"
 )
 
+// nodeHeartbeatInterval is the interval between processing heartbeats sent
+// during long-running node requests to keep the connection alive.
+const nodeHeartbeatInterval = 15 * time.Second
+
 // PicoMessage is the wire format for all Pico Protocol messages.
-type PicoMessage struct {
+// This is a local type alias for the canonical protocol.Message type.
-	Type      string         `json:"type"`
+type PicoMessage = picoproto.Message
-	ID        string         `json:"id,omitempty"`
-	SessionID string         `json:"session_id,omitempty"`
-	Timestamp int64          `json:"timestamp,omitempty"`
-	Payload   map[string]any `json:"payload,omitempty"`
-}
 
 // newMessage creates a PicoMessage with the given type and payload.
 func newMessage(msgType string, payload map[string]any) PicoMessage {
-	return PicoMessage{
+	return picoproto.NewMessage(msgType, payload)
-		Type:      msgType,
-		Timestamp: time.Now().UnixMilli(),
-		Payload:   payload,
-	}
 }
 
 // newError creates an error PicoMessage.
 func newError(code, message string) PicoMessage {
-	return newMessage(TypeError, map[string]any{
+	return picoproto.NewError(code, message)
-		"code":    code,
+}
-		"message": message,
+
-	})
+// Message type constants re-exported from pkg/pico/protocol for convenience.
+// The canonical definitions are in pkg/pico/protocol/protocol.go.
+const (
+	TypeMessageSend    = picoproto.TypeMessageSend
+	TypeMediaSend      = picoproto.TypeMediaSend
+	TypePing           = picoproto.TypePing
+	TypeMessageCreate  = picoproto.TypeMessageCreate
+	TypeMessageUpdate  = picoproto.TypeMessageUpdate
+	TypeMediaCreate    = picoproto.TypeMediaCreate
+	TypeTypingStart    = picoproto.TypeTypingStart
+	TypeTypingStop     = picoproto.TypeTypingStop
+	TypeError          = picoproto.TypeError
+	TypePong           = picoproto.TypePong
+	TypeNodeRequest    = picoproto.TypeNodeRequest
+	TypeNodeReply      = picoproto.TypeNodeReply
+	TypeNodeProcessing = picoproto.TypeNodeProcessing
+)
+
+// Ensure PicoMessage matches protocol.Message at compile time.
+var _ = func() struct{} {
+	// Type alias compatibility check
+	type _ = picoproto.Message
+	type _ = PicoMessage
+	return struct{}{}
+}()
+
+// PicoMessageTimestamp returns the current timestamp for Pico messages.
+func PicoMessageTimestamp() int64 {
+	return time.Now().UnixMilli()
 }

pkg/config/config.go

@@ -58,6 +58,7 @@ type Config struct {
 	Tools     ToolsConfig     `json:"tools"`
 	Heartbeat HeartbeatConfig `json:"heartbeat"`
 	Devices   DevicesConfig   `json:"devices"`
+	Swarm     SwarmConfig     `json:"swarm,omitempty"` // Swarm mode configuration
 }
 
 // MarshalJSON implements custom JSON marshaling for Config
@@ -900,3 +901,134 @@ func (t *ToolsConfig) IsToolEnabled(name string) bool {
 		return true
 	}
 }
+
+// SwarmConfig contains configuration for swarm mode.
+type SwarmConfig struct {
+	// Enabled enables swarm mode.
+	Enabled bool `json:"enabled" env:"PICOCLAW_SWARM_ENABLED"`
+
+	// NodeID is the unique identifier for this node.
+	NodeID string `json:"node_id,omitempty" env:"PICOCLAW_SWARM_NODE_ID"`
+
+	// Discovery configuration for NATS-based node discovery.
+	Discovery SwarmDiscoveryConfig `json:"discovery"`
+
+	// Handoff configuration for task handoff.
+	Handoff SwarmHandoffConfig `json:"handoff"`
+
+	// LoadMonitor configuration for load monitoring.
+	LoadMonitor SwarmLoadMonitorConfig `json:"load_monitor"`
+
+	// LeaderElection configuration for leader election.
+	LeaderElection SwarmLeaderElectionConfig `json:"leader_election"`
+}
+
+// SwarmDiscoveryConfig contains configuration for NATS-based node discovery.
+type SwarmDiscoveryConfig struct {
+	// NATSURL is the NATS server URL (required).
+	NATSURL string `json:"nats_url,omitempty" env:"PICOCLAW_SWARM_NATS_URL"`
+
+	// NATSCredsFile is the path to NATS credentials file (NKeys/JWT auth).
+	NATSCredsFile string `json:"nats_creds_file,omitempty"`
+
+	// NATSTLSCert is the path to the client TLS certificate for mTLS.
+	NATSTLSCert string `json:"nats_tls_cert,omitempty"`
+
+	// NATSTLSKey is the path to the client TLS key for mTLS.
+	NATSTLSKey string `json:"nats_tls_key,omitempty"`
+
+	// NATSTLSCACert is the path to the CA certificate for TLS verification.
+	NATSTLSCACert string `json:"nats_tls_ca_cert,omitempty"`
+
+	// HeartbeatInterval controls how often the node renews its KV entry (in seconds).
+	HeartbeatInterval int `json:"heartbeat_interval,omitempty"`
+
+	// MemberTTL is the TTL for member entries in the KV bucket (in seconds).
+	MemberTTL int `json:"member_ttl,omitempty"`
+
+	// SubjectPrefix overrides the default "picoclaw.swarm" subject prefix.
+	SubjectPrefix string `json:"subject_prefix,omitempty"`
+
+	// NodeTimeout is the timeout before marking a node as suspect (in seconds).
+	NodeTimeout int `json:"node_timeout,omitempty"`
+
+	// DeadNodeTimeout is the timeout before marking a node as dead (in seconds).
+	DeadNodeTimeout int `json:"dead_node_timeout,omitempty"`
+}
+
+// SwarmHandoffConfig contains configuration for task handoff.
+type SwarmHandoffConfig struct {
+	// Enabled enables task handoff.
+	Enabled bool `json:"enabled"`
+
+	// LoadThreshold is the load score threshold (0-1) above which
+	// tasks will be handed off to other nodes.
+	LoadThreshold float64 `json:"load_threshold,omitempty"`
+
+	// Timeout is the timeout for a handoff operation (in seconds).
+	Timeout int `json:"timeout,omitempty"`
+
+	// MaxRetries is the maximum number of retries for handoff.
+	MaxRetries int `json:"max_retries,omitempty"`
+
+	// RetryDelay is the delay between retries (in seconds).
+	RetryDelay int `json:"retry_delay,omitempty"`
+
+	// RequestTimeout is the timeout for a single NATS handoff request-reply (in seconds).
+	RequestTimeout int `json:"request_timeout,omitempty"`
+
+	// SharedSecret is the HMAC secret for message signing (base64 encoded or raw string).
+	// If empty, signing is disabled (NOT RECOMMENDED for production).
+	SharedSecret string `json:"shared_secret,omitempty" env:"PICOCLAW_SWARM_SHARED_SECRET"`
+
+	// EncryptionKey is the AES-256 key for encrypting session data (base64 encoded or raw string).
+	// Must be 32 bytes when decoded. If empty, encryption is disabled.
+	EncryptionKey string `json:"encryption_key,omitempty" env:"PICOCLAW_SWARM_ENCRYPTION_KEY"`
+
+	// RequireAuth enables strict authentication - reject unsigned messages.
+	RequireAuth bool `json:"require_auth"`
+
+	// RequireEncryption enables strict encryption - reject unencrypted session data.
+	RequireEncryption bool `json:"require_encryption"`
+}
+
+// SwarmLoadMonitorConfig contains configuration for load monitoring.
+type SwarmLoadMonitorConfig struct {
+	// Enabled enables load monitoring.
+	Enabled bool `json:"enabled"`
+
+	// Interval is the interval between load samples (in seconds).
+	Interval int `json:"interval,omitempty"`
+
+	// SampleSize is the number of samples to keep for averaging.
+	SampleSize int `json:"sample_size,omitempty"`
+
+	// CPUWeight is the weight for CPU usage in load score (0-1).
+	CPUWeight float64 `json:"cpu_weight,omitempty"`
+
+	// MemoryWeight is the weight for memory usage in load score (0-1).
+	MemoryWeight float64 `json:"memory_weight,omitempty"`
+
+	// SessionWeight is the weight for active sessions in load score (0-1).
+	SessionWeight float64 `json:"session_weight,omitempty"`
+
+	// RoutingRejectThreshold is the load score above which routing requests are rejected (0-1).
+	// Provides hysteresis to prevent oscillation. Default: 0.9
+	RoutingRejectThreshold float64 `json:"routing_reject_threshold,omitempty"`
+
+	// RoutingAcceptThreshold is the load score below which routing requests are accepted (0-1).
+	// Once rejected, load must drop below this to accept again. Default: 0.75
+	RoutingAcceptThreshold float64 `json:"routing_accept_threshold,omitempty"`
+}
+
+// SwarmLeaderElectionConfig contains configuration for leader election.
+type SwarmLeaderElectionConfig struct {
+	// Enabled enables leader election.
+	Enabled bool `json:"enabled"`
+
+	// LockTTL is how long the leader lock lives without renewal (in seconds).
+	LockTTL int `json:"lock_ttl,omitempty"`
+
+	// RenewalInterval is how often the leader renews its lock (in seconds).
+	RenewalInterval int `json:"renewal_interval,omitempty"`
+}

pkg/kv/bucket.go

@@ -0,0 +1,115 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Generic Key-Value storage abstraction
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+// Package kv provides a generic key-value storage abstraction.
+// It supports multiple backends (NATS JetStream, etcd, Consul, etc.)
+// with CAS (Compare-And-Swap) operations and change watching.
+package kv
+
+import "time"
+
+// BucketSpec defines the configuration for a bucket.
+type BucketSpec struct {
+	Name         string        // Bucket name
+	Description  string        // Human-readable description
+	TTL          time.Duration // TTL for entries
+	MaxValueSize int32         // Maximum value size
+	Storage      StorageType   // Storage backend
+}
+
+// StorageType defines the storage backend for a bucket.
+type StorageType string
+
+const (
+	StorageFile   StorageType = "file"
+	StorageMemory StorageType = "memory"
+)
+
+// BucketEntry represents a key-value entry in a bucket.
+type BucketEntry struct {
+	Key       string         // The key
+	Value     []byte         // The value
+	Revision  uint64         // Revision number (for CAS)
+	Operation EntryOperation // The operation that triggered this entry
+}
+
+// EntryOperation represents the type of operation on an entry.
+type EntryOperation string
+
+const (
+	EntryOperationPut    EntryOperation = "put"
+	EntryOperationDelete EntryOperation = "delete"
+	EntryOperationPurge  EntryOperation = "purge"
+)
+
+// BucketWatcher watches for changes in a bucket.
+type BucketWatcher interface {
+	// Updates returns a channel of bucket entry updates.
+	// The channel is closed when Stop() is called.
+	Updates() <-chan *BucketEntry
+
+	// Stop stops watching and closes the updates channel.
+	Stop()
+}
+
+// Bucket provides key-value storage with watch capabilities.
+//
+// This interface abstracts KV operations for different storage backends.
+// Implementations can use NATS JetStream KV, etcd, Consul, Redis, etc.
+type Bucket interface {
+	// Name returns the bucket name.
+	Name() string
+
+	// Get retrieves a value by key.
+	// Returns nil if key does not exist.
+	Get(key string) (*BucketEntry, error)
+
+	// Put stores a value under the given key (creates or updates).
+	Put(key string, value []byte) error
+
+	// Create stores a value only if the key does not exist.
+	// Returns the revision number of the new entry.
+	// Returns an error if the key already exists.
+	Create(key string, value []byte) (uint64, error)
+
+	// Update updates a value with CAS (Compare-And-Swap) semantics.
+	// The operation only succeeds if the entry's revision matches the expected revision.
+	// Returns the new revision number.
+	// Returns an error if the revision doesn't match (CAS failure).
+	Update(key string, value []byte, revision uint64) (uint64, error)
+
+	// Delete removes a key.
+	Delete(key string) error
+
+	// Keys returns all keys in the bucket.
+	Keys() ([]string, error)
+
+	// Watch starts watching for changes in the bucket.
+	// If keyPrefix is provided, only watch keys with that prefix.
+	// Returns a BucketWatcher that can be stopped.
+	Watch(keyPrefix string) (BucketWatcher, error)
+
+	// WatchAll watches all keys in the bucket.
+	WatchAll() (BucketWatcher, error)
+
+	// Close closes the bucket and releases resources.
+	Close() error
+}
+
+// BucketFactory creates buckets of different types.
+type BucketFactory interface {
+	// CreateBucket creates a new bucket with the given specification.
+	CreateBucket(spec BucketSpec) (Bucket, error)
+
+	// GetBucket returns an existing bucket by name.
+	GetBucket(name string) (Bucket, error)
+
+	// CreateIfNotExists creates a bucket if it doesn't exist, or returns the existing one.
+	CreateIfNotExists(spec BucketSpec) (Bucket, error)
+
+	// Close closes all buckets and releases resources.
+	Close() error
+}

pkg/kv/nats.go

@@ -0,0 +1,253 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Generic Key-Value storage abstraction - NATS JetStream implementation
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package kv
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/nats-io/nats.go"
+)
+
+// NATSBucketFactory implements BucketFactory using NATS JetStream KV.
+type NATSBucketFactory struct {
+	js      nats.JetStreamContext
+	buckets map[string]Bucket
+	mu      sync.RWMutex
+}
+
+// NewNATSBucketFactory creates a new NATS-backed bucket factory.
+func NewNATSBucketFactory(js nats.JetStreamContext) *NATSBucketFactory {
+	return &NATSBucketFactory{
+		js:      js,
+		buckets: make(map[string]Bucket),
+	}
+}
+
+// CreateBucket creates a new bucket with the given specification.
+func (nf *NATSBucketFactory) CreateBucket(spec BucketSpec) (Bucket, error) {
+	nf.mu.Lock()
+	defer nf.mu.Unlock()
+
+	// Check if already exists
+	if _, exists := nf.buckets[spec.Name]; exists {
+		return nil, fmt.Errorf("bucket %s already exists", spec.Name)
+	}
+
+	storage := nats.FileStorage
+	if spec.Storage == StorageMemory {
+		storage = nats.MemoryStorage
+	}
+
+	kv, err := nf.js.CreateKeyValue(&nats.KeyValueConfig{
+		Bucket:       spec.Name,
+		Description:  spec.Description,
+		MaxValueSize: spec.MaxValueSize,
+		TTL:          spec.TTL,
+		Storage:      storage,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create KV bucket %s: %w", spec.Name, err)
+	}
+
+	bucket := &natsBucket{
+		kv:   kv,
+		spec: spec,
+	}
+	nf.buckets[spec.Name] = bucket
+
+	return bucket, nil
+}
+
+// GetBucket returns an existing bucket by name.
+func (nf *NATSBucketFactory) GetBucket(name string) (Bucket, error) {
+	nf.mu.RLock()
+	defer nf.mu.RUnlock()
+
+	if b, exists := nf.buckets[name]; exists {
+		return b, nil
+	}
+
+	// Try to load from NATS
+	kv, err := nf.js.KeyValue(name)
+	if err != nil {
+		return nil, fmt.Errorf("bucket %s not found: %w", name, err)
+	}
+
+	bucket := &natsBucket{
+		kv:   kv,
+		spec: BucketSpec{Name: name},
+	}
+	nf.buckets[name] = bucket
+
+	return bucket, nil
+}
+
+// CreateIfNotExists creates a bucket if it doesn't exist.
+func (nf *NATSBucketFactory) CreateIfNotExists(spec BucketSpec) (Bucket, error) {
+	b, err := nf.GetBucket(spec.Name)
+	if err == nil {
+		return b, nil
+	}
+
+	return nf.CreateBucket(spec)
+}
+
+// Close closes all buckets.
+func (nf *NATSBucketFactory) Close() error {
+	nf.mu.Lock()
+	defer nf.mu.Unlock()
+
+	var lastErr error
+	for name := range nf.buckets {
+		delete(nf.buckets, name)
+	}
+
+	return lastErr
+}
+
+// natsBucket implements Bucket using NATS JetStream KV.
+type natsBucket struct {
+	kv   nats.KeyValue
+	spec BucketSpec
+}
+
+// Name returns the bucket name.
+func (b *natsBucket) Name() string {
+	return b.spec.Name
+}
+
+// Get retrieves a value by key.
+func (b *natsBucket) Get(key string) (*BucketEntry, error) {
+	entry, err := b.kv.Get(key)
+	if err != nil {
+		if err == nats.ErrKeyNotFound {
+			return nil, nil
+		}
+		return nil, err
+	}
+
+	return &BucketEntry{
+		Key:      entry.Key(),
+		Value:    entry.Value(),
+		Revision: entry.Revision(),
+	}, nil
+}
+
+// Put stores a value under the given key.
+func (b *natsBucket) Put(key string, value []byte) error {
+	_, err := b.kv.Put(key, value)
+	return err
+}
+
+// Create puts a key only if it doesn't exist (Create operation).
+func (b *natsBucket) Create(key string, value []byte) (uint64, error) {
+	return b.kv.Create(key, value)
+}
+
+// Update updates a key with CAS (Compare-And-Swap).
+func (b *natsBucket) Update(key string, value []byte, revision uint64) (uint64, error) {
+	return b.kv.Update(key, value, revision)
+}
+
+// Delete removes a key.
+func (b *natsBucket) Delete(key string) error {
+	return b.kv.Delete(key)
+}
+
+// Keys returns all keys in the bucket.
+func (b *natsBucket) Keys() ([]string, error) {
+	return b.kv.Keys()
+}
+
+// Watch starts watching for changes in the bucket.
+func (b *natsBucket) Watch(keyPrefix string) (BucketWatcher, error) {
+	watcher, err := b.kv.Watch(keyPrefix)
+	if err != nil {
+		return nil, err
+	}
+
+	return &natsBucketWatcher{watcher: watcher}, nil
+}
+
+// WatchAll watches all keys in the bucket.
+func (b *natsBucket) WatchAll() (BucketWatcher, error) {
+	watcher, err := b.kv.WatchAll()
+	if err != nil {
+		return nil, err
+	}
+
+	return &natsBucketWatcher{watcher: watcher}, nil
+}
+
+// Close closes the bucket.
+func (b *natsBucket) Close() error {
+	// NATS KV buckets are managed by JetStream, not by individual holders
+	// We don't actually delete the bucket, just release our reference
+	return nil
+}
+
+// natsBucketWatcher implements BucketWatcher using NATS KV watcher.
+type natsBucketWatcher struct {
+	watcher nats.KeyWatcher
+	updates chan *BucketEntry
+	once    sync.Once
+}
+
+// Updates returns a channel of bucket entry updates.
+func (w *natsBucketWatcher) Updates() <-chan *BucketEntry {
+	if w.updates == nil {
+		w.updates = make(chan *BucketEntry, 32)
+		go w.forwardUpdates()
+	}
+	return w.updates
+}
+
+// forwardUpdates forwards NATS watcher updates to our channel.
+func (w *natsBucketWatcher) forwardUpdates() {
+	for entry := range w.watcher.Updates() {
+		if entry == nil {
+			continue
+		}
+
+		var op EntryOperation
+		switch entry.Operation() {
+		case nats.KeyValuePut:
+			op = EntryOperationPut
+		case nats.KeyValueDelete:
+			op = EntryOperationDelete
+		case nats.KeyValuePurge:
+			op = EntryOperationPurge
+		default:
+			continue
+		}
+
+		bEntry := &BucketEntry{
+			Key:       entry.Key(),
+			Value:     entry.Value(),
+			Revision:  entry.Revision(),
+			Operation: op,
+		}
+
+		select {
+		case w.updates <- bEntry:
+		default:
+			// Channel full, drop the update
+			// In production, you might want to handle this differently
+		}
+	}
+}
+
+// Stop stops watching.
+func (w *natsBucketWatcher) Stop() {
+	w.once.Do(func() {
+		w.watcher.Stop()
+		if w.updates != nil {
+			close(w.updates)
+		}
+	})
+}

pkg/pico/addr.go

@@ -0,0 +1,22 @@
+// Package pico provides a reusable WebSocket client for the Pico Protocol.
+//
+// In addition to the low-level Client, this package defines shared types and
+// helpers used by both the Pico channel (server) and the swarm subsystem
+// (client) for inter-node communication.
+//
+// The Client type encapsulates the connect → send → receive → close lifecycle
+// for a single request-reply exchange with a Pico WebSocket endpoint. It is
+// intentionally stateless: each call to SendRequest opens a new connection,
+// performs the exchange, and closes the connection.
+//
+// This package depends only on pkg/pico/protocol and gorilla/websocket;
+// it has no knowledge of swarm, channels, or any other higher-level construct.
+package pico
+
+import "fmt"
+
+// BuildNodeAddr constructs a host:port address string for inter-node
+// communication. It replaces the scattered fmt.Sprintf("%s:%d", ...) calls.
+func BuildNodeAddr(addr string, port int) string {
+	return fmt.Sprintf("%s:%d", addr, port)
+}

pkg/pico/client.go

@@ -0,0 +1,107 @@
+package pico
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/websocket"
+
+	"github.com/sipeed/picoclaw/pkg/pico/protocol"
+)
+
+// DefaultReadTimeout is the maximum time to wait for a reply after sending.
+// For inter-node communication, LLM responses may take longer than typical HTTP requests.
+const DefaultReadTimeout = 2 * time.Minute
+
+// Client is a lightweight, stateless Pico WebSocket client.
+// Each SendRequest call dials a new connection, performs a single
+// request-reply exchange, and closes the connection.
+type Client struct {
+	token string
+}
+
+// NewClient creates a new Pico WebSocket client.
+// If token is non-empty it is sent as a Bearer token in the upgrade request.
+func NewClient(token string) *Client {
+	return &Client{token: token}
+}
+
+// BuildWSURL constructs the canonical Pico WebSocket URL for a given
+// host address and session ID.
+func BuildWSURL(addr, sessionID string) string {
+	return fmt.Sprintf("ws://%s/pico/ws?session_id=%s", addr, sessionID)
+}
+
+// SendRequest dials the target Pico WebSocket endpoint, sends msg, and blocks
+// until a single reply message is received (or the context / read timeout fires).
+//
+// The caller is responsible for constructing the outbound protocol.Message
+// (including Type, ID, Payload, etc.) and for interpreting the reply.
+//
+// For long-running requests, the server may send TypeNodeProcessing messages
+// to keep the connection alive. The client resets the read timeout on each
+// processing message until the final reply is received.
+func (c *Client) SendRequest(
+	ctx context.Context,
+	addr, sessionID string,
+	msg protocol.Message,
+) (protocol.Message, error) {
+	wsURL := BuildWSURL(addr, sessionID)
+
+	header := http.Header{}
+	if c.token != "" {
+		header.Set("Authorization", "Bearer "+c.token)
+	}
+
+	dialer := websocket.Dialer{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
+
+	conn, resp, err := dialer.DialContext(ctx, wsURL, header)
+	if err != nil {
+		if resp != nil && resp.Body != nil {
+			resp.Body.Close()
+			return protocol.Message{}, fmt.Errorf(
+				"pico WebSocket dial failed: %s (status: %d)",
+				err.Error(), resp.StatusCode,
+			)
+		}
+		return protocol.Message{}, fmt.Errorf("pico WebSocket dial failed: %w", err)
+	}
+	if resp != nil && resp.Body != nil {
+		resp.Body.Close()
+	}
+	defer conn.Close()
+
+	if writeErr := conn.WriteJSON(msg); writeErr != nil {
+		return protocol.Message{}, fmt.Errorf("failed to send pico request: %w", writeErr)
+	}
+
+	// Read loop that handles processing heartbeat messages
+	for {
+		// Set read deadline before each read
+		conn.SetReadDeadline(time.Now().Add(DefaultReadTimeout))
+
+		_, rawMsg, err := conn.ReadMessage()
+		if err != nil {
+			return protocol.Message{}, fmt.Errorf("failed to read pico reply: %w", err)
+		}
+
+		var reply protocol.Message
+		if err := json.Unmarshal(rawMsg, &reply); err != nil {
+			return protocol.Message{}, fmt.Errorf("failed to parse pico reply: %w", err)
+		}
+
+		// Handle processing heartbeat - reset timeout and continue waiting
+		if reply.Type == protocol.TypeNodeProcessing {
+			continue
+		}
+
+		// Return on final reply or error
+		return reply, nil
+	}
+}

pkg/pico/node_client.go

@@ -0,0 +1,123 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package pico
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/google/uuid"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+	"github.com/sipeed/picoclaw/pkg/pico/protocol"
+)
+
+// PicoNodeClient sends inter-node messages by connecting to a target node's
+// Pico WebSocket endpoint. It delegates the low-level WebSocket lifecycle to
+// Client and focuses on swarm-specific payload construction.
+type PicoNodeClient struct {
+	sourceNodeID string
+	client       *Client
+}
+
+// NewPicoNodeClient creates a new Pico-based inter-node client.
+func NewPicoNodeClient(sourceNodeID, token string) *PicoNodeClient {
+	return &PicoNodeClient{
+		sourceNodeID: sourceNodeID,
+		client:       NewClient(token),
+	}
+}
+
+// SendMessage connects to the target node's Pico WebSocket, sends a node.request
+// with action "message", and blocks until a node.reply is received (or timeout).
+func (c *PicoNodeClient) SendMessage(
+	ctx context.Context,
+	targetAddr, targetNodeID, content, channel, chatID, senderID string,
+) (string, error) {
+	payload := NewMessagePayload(c.sourceNodeID, content, channel, chatID, senderID)
+	return c.sendRequest(ctx, targetAddr, targetNodeID, payload)
+}
+
+// SendNodeAction sends an action-based request to a target node via Pico.
+// The payload must contain an "action" key. Returns the raw reply payload.
+func (c *PicoNodeClient) SendNodeAction(
+	ctx context.Context,
+	targetAddr string,
+	payload NodePayload,
+) (NodePayload, error) {
+	requestID := uuid.New().String()
+	payload[PayloadKeySourceNodeID] = c.sourceNodeID
+	payload[PayloadKeyRequestID] = requestID
+
+	logger.InfoCF("pico", "Sending node action via Pico", map[string]any{
+		"action":      payload.Action(),
+		"target_addr": targetAddr,
+		"request_id":  requestID,
+	})
+
+	return c.doSend(ctx, targetAddr, requestID, payload)
+}
+
+// sendRequest is the internal method for sending a request and returning the "response" string.
+func (c *PicoNodeClient) sendRequest(
+	ctx context.Context,
+	targetAddr, targetNodeID string,
+	payload NodePayload,
+) (string, error) {
+	requestID := uuid.New().String()
+	payload[PayloadKeyRequestID] = requestID
+
+	logger.InfoCF("pico", "Sending node request via Pico", map[string]any{
+		"action":         payload.Action(),
+		"target_node_id": targetNodeID,
+		"target_addr":    targetAddr,
+		"request_id":     requestID,
+	})
+
+	replyPayload, err := c.doSend(ctx, targetAddr, requestID, payload)
+	if err != nil {
+		return "", err
+	}
+
+	if errStr := replyPayload.ErrorMsg(); errStr != "" {
+		return "", fmt.Errorf("node error: %s", errStr)
+	}
+
+	return replyPayload.Response(), nil
+}
+
+// doSend builds a protocol.Message, delegates to Client.SendRequest,
+// and validates the reply envelope before returning the payload.
+func (c *PicoNodeClient) doSend(
+	ctx context.Context,
+	targetAddr, requestID string,
+	payload NodePayload,
+) (NodePayload, error) {
+	reqMsg := protocol.Message{
+		Type:      protocol.TypeNodeRequest,
+		ID:        requestID,
+		SessionID: c.sourceNodeID,
+		Timestamp: time.Now().UnixMilli(),
+		Payload:   payload,
+	}
+
+	reply, err := c.client.SendRequest(ctx, targetAddr, c.sourceNodeID, reqMsg)
+	if err != nil {
+		return nil, err
+	}
+
+	if reply.Type != protocol.TypeNodeReply {
+		return nil, fmt.Errorf("unexpected reply type: %s (expected %s)", reply.Type, protocol.TypeNodeReply)
+	}
+
+	replyPayload := NodePayload(reply.Payload)
+	if replyPayload.RequestID() != requestID {
+		return nil, fmt.Errorf("request ID mismatch: got %s, want %s", replyPayload.RequestID(), requestID)
+	}
+
+	return replyPayload, nil
+}

pkg/pico/node_payload.go

@@ -0,0 +1,132 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package pico
+
+// NodePayload is the typed payload exchanged between nodes via the
+// Pico channel node.request / node.reply protocol. It provides named
+// constants for field keys and typed accessor methods so that callers
+// never need to use raw string literals.
+type NodePayload map[string]any
+
+// Payload field key constants.
+const (
+	PayloadKeyAction       = "action"
+	PayloadKeyRequestID    = "request_id"
+	PayloadKeySourceNodeID = "source_node_id"
+	PayloadKeyContent      = "content"
+	PayloadKeyChannel      = "channel"
+	PayloadKeyChatID       = "chat_id"
+	PayloadKeySenderID     = "sender_id"
+	PayloadKeyMetadata     = "metadata"
+	PayloadKeyError        = "error"
+	PayloadKeyResponse     = "response"
+	PayloadKeyRequest      = "request"          // nested handoff request object
+	PayloadKeyHandoffResp  = "handoff_response" // nested handoff response object
+)
+
+// Node action constants used for action-based routing over Pico.
+const (
+	NodeActionMessage        = "message"
+	NodeActionStatus         = "status"
+	NodeActionHandoffRequest = "handoff_request"
+)
+
+// ---------------------------------------------------------------------------
+// Accessors
+// ---------------------------------------------------------------------------
+
+// str is a small helper that extracts a string value from the payload.
+func (p NodePayload) str(key string) string {
+	v, _ := p[key].(string)
+	return v
+}
+
+// Action returns the action field (e.g. "message", "handoff_request").
+func (p NodePayload) Action() string { return p.str(PayloadKeyAction) }
+
+// RequestID returns the request_id field.
+func (p NodePayload) RequestID() string { return p.str(PayloadKeyRequestID) }
+
+// SourceNodeID returns the source_node_id field.
+func (p NodePayload) SourceNodeID() string { return p.str(PayloadKeySourceNodeID) }
+
+// Content returns the content field.
+func (p NodePayload) Content() string { return p.str(PayloadKeyContent) }
+
+// Channel returns the channel field.
+func (p NodePayload) Channel() string { return p.str(PayloadKeyChannel) }
+
+// ChatID returns the chat_id field.
+func (p NodePayload) ChatID() string { return p.str(PayloadKeyChatID) }
+
+// SenderID returns the sender_id field.
+func (p NodePayload) SenderID() string { return p.str(PayloadKeySenderID) }
+
+// ErrorMsg returns the error field.
+func (p NodePayload) ErrorMsg() string { return p.str(PayloadKeyError) }
+
+// Response returns the response field.
+func (p NodePayload) Response() string { return p.str(PayloadKeyResponse) }
+
+// Metadata extracts the metadata map, converting map[string]any to map[string]string.
+func (p NodePayload) Metadata() map[string]string {
+	raw, ok := p[PayloadKeyMetadata]
+	if !ok {
+		return nil
+	}
+	m, ok := raw.(map[string]any)
+	if !ok {
+		return nil
+	}
+	result := make(map[string]string, len(m))
+	for k, v := range m {
+		if s, ok := v.(string); ok {
+			result[k] = s
+		}
+	}
+	return result
+}
+
+// RawValue returns the raw value for an arbitrary key.
+func (p NodePayload) RawValue(key string) (any, bool) {
+	v, ok := p[key]
+	return v, ok
+}
+
+// ---------------------------------------------------------------------------
+// Builder helpers
+// ---------------------------------------------------------------------------
+
+// NewNodePayload creates an empty NodePayload.
+func NewNodePayload() NodePayload {
+	return make(NodePayload)
+}
+
+// NewMessagePayload creates a NodePayload pre-filled for a "message" action.
+func NewMessagePayload(sourceNodeID, content, channel, chatID, senderID string) NodePayload {
+	return NodePayload{
+		PayloadKeyAction:       NodeActionMessage,
+		PayloadKeySourceNodeID: sourceNodeID,
+		PayloadKeyContent:      content,
+		PayloadKeyChannel:      channel,
+		PayloadKeyChatID:       chatID,
+		PayloadKeySenderID:     senderID,
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Reply constructors
+// ---------------------------------------------------------------------------
+
+// ErrorReply creates a reply payload carrying an error message.
+func ErrorReply(msg string) NodePayload {
+	return NodePayload{PayloadKeyError: msg}
+}
+
+// ResponseReply creates a reply payload carrying a string response.
+func ResponseReply(response string) NodePayload {
+	return NodePayload{PayloadKeyResponse: response}
+}

pkg/pico/protocol/protocol.go

@@ -0,0 +1,65 @@
+// Package protocol defines the Pico Protocol wire format shared by
+// the Pico channel (server) and the swarm PicoNodeClient (client).
+// This package has zero internal dependencies to stay at the bottom
+// of the dependency graph.
+package protocol
+
+import "time"
+
+// Message type constants for the Pico Protocol.
+const (
+	// TypeMessageSend is sent from client to server.
+	TypeMessageSend = "message.send"
+	// TypeMediaSend is sent from client to server for media.
+	TypeMediaSend = "media.send"
+	// TypePing is a client ping.
+	TypePing = "ping"
+
+	// TypeMessageCreate is sent from server to client.
+	TypeMessageCreate = "message.create"
+	// TypeMessageUpdate is sent from server to client for message updates.
+	TypeMessageUpdate = "message.update"
+	// TypeMediaCreate is sent from server to client for media.
+	TypeMediaCreate = "media.create"
+	// TypeTypingStart indicates typing has started.
+	TypeTypingStart = "typing.start"
+	// TypeTypingStop indicates typing has stopped.
+	TypeTypingStop = "typing.stop"
+	// TypeError is an error message.
+	TypeError = "error"
+	// TypePong is a server pong reply.
+	TypePong = "pong"
+
+	// TypeNodeRequest is for inter-node swarm communication.
+	TypeNodeRequest = "node.request"
+	// TypeNodeReply is the reply for inter-node swarm communication.
+	TypeNodeReply = "node.reply"
+	// TypeNodeProcessing is sent periodically while processing a long-running request.
+	TypeNodeProcessing = "node.processing"
+)
+
+// Message is the wire format for all Pico Protocol messages.
+type Message struct {
+	Type      string         `json:"type"`
+	ID        string         `json:"id,omitempty"`
+	SessionID string         `json:"session_id,omitempty"`
+	Timestamp int64          `json:"timestamp,omitempty"`
+	Payload   map[string]any `json:"payload,omitempty"`
+}
+
+// NewMessage creates a Message with the given type, payload, and current timestamp.
+func NewMessage(msgType string, payload map[string]any) Message {
+	return Message{
+		Type:      msgType,
+		Timestamp: time.Now().UnixMilli(),
+		Payload:   payload,
+	}
+}
+
+// NewError creates an error Message with code and human-readable message.
+func NewError(code, message string) Message {
+	return NewMessage(TypeError, map[string]any{
+		"code":    code,
+		"message": message,
+	})
+}

pkg/pico/types.go

@@ -0,0 +1,45 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package pico
+
+// SessionMessage represents a message in a session.
+// This is shared across handoff, session transfer, and inter-node communication.
+type SessionMessage struct {
+	Role      string         `json:"role"`
+	Content   string         `json:"content"`
+	Timestamp int64          `json:"timestamp,omitempty"`
+	ToolCalls []ToolCallData `json:"tool_calls,omitempty"`
+}
+
+// ToolCallData represents tool call information in a message.
+type ToolCallData struct {
+	ID        string         `json:"id"`
+	Name      string         `json:"name"`
+	Arguments map[string]any `json:"arguments"`
+	Result    string         `json:"result,omitempty"`
+	Extra     map[string]any `json:"extra,omitempty"`
+}
+
+// DirectMessage represents a direct message sent to another node.
+type DirectMessage struct {
+	MessageID    string            `json:"message_id"`
+	SourceNodeID string            `json:"source_node_id"`
+	TargetNodeID string            `json:"target_node_id"`
+	Action       string            `json:"action,omitempty"`
+	Content      string            `json:"content"`
+	Channel      string            `json:"channel"`
+	ChatID       string            `json:"chat_id"`
+	SenderID     string            `json:"sender_id"`
+	Metadata     map[string]string `json:"metadata,omitempty"`
+	Timestamp    int64             `json:"timestamp"`
+}
+
+// DirectMessageResponse represents a response to a direct message.
+type DirectMessageResponse struct {
+	MessageID string `json:"message_id"`
+	Response  string `json:"response"`
+	Error     string `json:"error,omitempty"`
+}

pkg/swarm/bucket_config.go

@@ -0,0 +1,103 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"github.com/sipeed/picoclaw/pkg/kv"
+)
+
+// BucketType identifies the type of bucket.
+type BucketType string
+
+const (
+	BucketTypeMembers BucketType = "members"
+	BucketTypeStatus  BucketType = "status"
+	BucketTypeLeader  BucketType = "leader"
+)
+
+// DefaultBucketSpecs returns the default bucket specifications for all bucket types.
+func DefaultBucketSpecs() map[BucketType]kv.BucketSpec {
+	return map[BucketType]kv.BucketSpec{
+		BucketTypeMembers: {
+			Name:         "swarm_members",
+			Description:  "PicoClaw Swarm Node Membership",
+			TTL:          DefaultMemberTTL,
+			MaxValueSize: 1024,
+			Storage:      kv.StorageFile,
+		},
+		BucketTypeStatus: {
+			Name:         "swarm_status",
+			Description:  "PicoClaw Swarm Node Detailed Status",
+			TTL:          DefaultDetailedStatusTTL,
+			MaxValueSize: 4096,
+			Storage:      kv.StorageMemory,
+		},
+		BucketTypeLeader: {
+			Name:         "swarm_leader",
+			Description:  "PicoClaw Swarm Leader Election Lock",
+			TTL:          DefaultLeaderLockTTL,
+			MaxValueSize: 512,
+			Storage:      kv.StorageMemory,
+		},
+	}
+}
+
+// MemberBucketSpec returns the specification for the members bucket.
+func MemberBucketSpec() kv.BucketSpec {
+	return DefaultBucketSpecs()[BucketTypeMembers]
+}
+
+// StatusBucketSpec returns the specification for the status bucket.
+func StatusBucketSpec() kv.BucketSpec {
+	return DefaultBucketSpecs()[BucketTypeStatus]
+}
+
+// LeaderBucketSpec returns the specification for the leader bucket.
+func LeaderBucketSpec() kv.BucketSpec {
+	return DefaultBucketSpecs()[BucketTypeLeader]
+}
+
+// BucketSet provides access to all buckets used by the swarm.
+type BucketSet struct {
+	Members kv.Bucket
+	Status  kv.Bucket
+	Leader  kv.Bucket
+	factory kv.BucketFactory
+}
+
+// NewBucketSet creates a new bucket set using the given factory.
+func NewBucketSet(factory kv.BucketFactory) (*BucketSet, error) {
+	bs := &BucketSet{factory: factory}
+
+	var err error
+	specs := DefaultBucketSpecs()
+
+	// Create or get members bucket
+	bs.Members, err = factory.CreateIfNotExists(specs[BucketTypeMembers])
+	if err != nil {
+		return nil, err
+	}
+
+	// Create or get status bucket
+	bs.Status, err = factory.CreateIfNotExists(specs[BucketTypeStatus])
+	if err != nil {
+		return nil, err
+	}
+
+	// Create or get leader bucket
+	bs.Leader, err = factory.CreateIfNotExists(specs[BucketTypeLeader])
+	if err != nil {
+		return nil, err
+	}
+
+	return bs, nil
+}
+
+// Close closes all buckets in the set.
+func (bs *BucketSet) Close() error {
+	return bs.factory.Close()
+}

pkg/swarm/config.go

@@ -0,0 +1,269 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// Config contains all configuration for swarm mode.
+type Config struct {
+	// Enabled enables swarm mode.
+	Enabled bool `json:"enabled" env:"PICOCLAW_SWARM_ENABLED"`
+
+	// NodeID is the unique identifier for this node.
+	// If empty, a hostname-based ID will be generated.
+	NodeID string `json:"node_id,omitempty" env:"PICOCLAW_SWARM_NODE_ID"`
+
+	// Discovery configuration for node discovery via NATS.
+	Discovery DiscoveryConfig `json:"discovery"`
+
+	// Handoff configuration for task handoff.
+	Handoff HandoffConfig `json:"handoff"`
+
+	// LoadMonitor configuration for load monitoring.
+	LoadMonitor LoadMonitorConfig `json:"load_monitor"`
+
+	// LeaderElection configuration for leader election.
+	LeaderElection LeaderElectionConfig `json:"leader_election"`
+
+	// Metrics configuration for observability.
+	Metrics MetricsConfig `json:"metrics"`
+}
+
+// DiscoveryConfig contains configuration for NATS-based node discovery.
+type DiscoveryConfig struct {
+	// NATSURL is the NATS server URL (required).
+	NATSURL string `json:"nats_url,omitempty" env:"PICOCLAW_SWARM_NATS_URL"`
+
+	// NATSCredsFile is the path to NATS credentials file (NKeys/JWT auth).
+	NATSCredsFile string `json:"nats_creds_file,omitempty" env:"PICOCLAW_SWARM_NATS_CREDS_FILE"`
+
+	// NATSTLSCert is the path to the client TLS certificate for mTLS.
+	NATSTLSCert string `json:"nats_tls_cert,omitempty"`
+
+	// NATSTLSKey is the path to the client TLS key for mTLS.
+	NATSTLSKey string `json:"nats_tls_key,omitempty"`
+
+	// NATSTLSCACert is the path to the CA certificate for TLS verification.
+	NATSTLSCACert string `json:"nats_tls_ca_cert,omitempty"`
+
+	// HeartbeatInterval controls how often the node renews its KV entry.
+	HeartbeatInterval Duration `json:"heartbeat_interval,omitempty"`
+
+	// MemberTTL is the TTL for member entries in the KV bucket.
+	MemberTTL Duration `json:"member_ttl,omitempty"`
+
+	// SubjectPrefix overrides the default "picoclaw.swarm" subject prefix.
+	SubjectPrefix string `json:"subject_prefix,omitempty"`
+
+	// NodeTimeout is the timeout before marking a node as suspect.
+	NodeTimeout Duration `json:"node_timeout,omitempty"`
+
+	// DeadNodeTimeout is the timeout before marking a node as dead.
+	DeadNodeTimeout Duration `json:"dead_node_timeout,omitempty"`
+}
+
+// HandoffConfig contains configuration for task handoff.
+type HandoffConfig struct {
+	// Enabled enables task handoff.
+	Enabled bool `json:"enabled"`
+
+	// LoadThreshold is the load score threshold (0-1) above which
+	// tasks will be handed off to other nodes.
+	LoadThreshold float64 `json:"load_threshold,omitempty"`
+
+	// Timeout is the timeout for a handoff operation.
+	Timeout Duration `json:"timeout,omitempty"`
+
+	// MaxRetries is the maximum number of retries for handoff.
+	MaxRetries int `json:"max_retries,omitempty"`
+
+	// RetryDelay is the delay between retries.
+	RetryDelay Duration `json:"retry_delay,omitempty"`
+
+	// RequestTimeout is the timeout for a single NATS request-reply handoff.
+	RequestTimeout Duration `json:"request_timeout,omitempty"`
+
+	// MaxSessionHistory is the maximum number of recent session messages to include in handoff.
+	// Set to 0 to send all messages (not recommended for production). Default: 10
+	MaxSessionHistory int `json:"max_session_history,omitempty"`
+
+	// Crypto contains security configuration for handoff.
+	Crypto CryptoConfig `json:"crypto"`
+}
+
+// LoadMonitorConfig contains configuration for load monitoring.
+type LoadMonitorConfig struct {
+	// Enabled enables load monitoring.
+	Enabled bool `json:"enabled"`
+
+	// Interval is the interval between load samples.
+	Interval Duration `json:"interval,omitempty"`
+
+	// SampleSize is the number of samples to keep for averaging.
+	SampleSize int `json:"sample_size,omitempty"`
+
+	// CPUWeight is the weight for CPU usage in load score (0-1).
+	CPUWeight float64 `json:"cpu_weight,omitempty"`
+
+	// MemoryWeight is the weight for memory usage in load score (0-1).
+	MemoryWeight float64 `json:"memory_weight,omitempty"`
+
+	// SessionWeight is the weight for active sessions in load score (0-1).
+	SessionWeight float64 `json:"session_weight,omitempty"`
+
+	// OffloadThreshold is the load score threshold above which tasks should be offloaded (0-1).
+	OffloadThreshold float64 `json:"offload_threshold,omitempty"`
+
+	// RoutingRejectThreshold is the load score above which routing requests are rejected (0-1).
+	// This provides hysteresis to prevent oscillation when load is near threshold.
+	RoutingRejectThreshold float64 `json:"routing_reject_threshold,omitempty"`
+
+	// RoutingAcceptThreshold is the load score below which routing requests are accepted (0-1).
+	// Provides hysteresis - once rejected, load must drop below this to accept again.
+	RoutingAcceptThreshold float64 `json:"routing_accept_threshold,omitempty"`
+
+	// MaxMemoryBytes is the maximum memory to use for normalization (default: 1GB).
+	MaxMemoryBytes uint64 `json:"max_memory_bytes,omitempty"`
+
+	// MaxGoroutines is the maximum goroutine count for normalization (default: 1000).
+	MaxGoroutines int `json:"max_goroutines,omitempty"`
+
+	// MaxSessions is the maximum session count for normalization (default: 100).
+	MaxSessions int `json:"max_sessions,omitempty"`
+}
+
+// LeaderElectionConfig contains configuration for leader election.
+type LeaderElectionConfig struct {
+	// Enabled enables leader election.
+	Enabled bool `json:"enabled"`
+
+	// LockTTL is how long the leader lock lives without renewal.
+	LockTTL Duration `json:"lock_ttl,omitempty"`
+
+	// RenewalInterval is how often the leader renews its lock.
+	// Must be less than LockTTL.
+	RenewalInterval Duration `json:"renewal_interval,omitempty"`
+}
+
+// CryptoConfig contains cryptographic settings for secure swarm communication.
+type CryptoConfig struct {
+	// SharedSecret is the HMAC secret for message signing (base64 encoded or raw string).
+	// If empty, signing is disabled (NOT RECOMMENDED for production).
+	SharedSecret string `json:"shared_secret,omitempty" env:"PICOCLAW_SWARM_SHARED_SECRET"`
+
+	// EncryptionKey is the AES-256 key for encrypting session data (base64 encoded or raw string).
+	// Must be 32 bytes when decoded. If empty, encryption is disabled.
+	EncryptionKey string `json:"encryption_key,omitempty" env:"PICOCLAW_SWARM_ENCRYPTION_KEY"`
+
+	// RequireAuth enables strict authentication - reject unsigned messages.
+	RequireAuth bool `json:"require_auth"`
+
+	// RequireEncryption enables strict encryption - reject unencrypted session data.
+	RequireEncryption bool `json:"require_encryption"`
+}
+
+// MetricsConfig contains configuration for metrics collection.
+type MetricsConfig struct {
+	// Enabled enables metrics collection.
+	Enabled bool `json:"enabled"`
+
+	// ExportInterval is how often to export metrics.
+	ExportInterval Duration `json:"export_interval,omitempty"`
+
+	// PrometheusEnabled enables Prometheus format export.
+	PrometheusEnabled bool `json:"prometheus_enabled"`
+
+	// PrometheusEndpoint is the HTTP endpoint for Prometheus metrics.
+	PrometheusEndpoint string `json:"prometheus_endpoint,omitempty"`
+}
+
+// Duration is a wrapper around time.Duration for JSON parsing.
+type Duration struct {
+	time.Duration
+}
+
+// UnmarshalJSON parses a duration from JSON.
+// Supports:
+//   - String: Go duration format, e.g. "5s", "100ms", "2m30s"
+//   - Number: interpreted as seconds (e.g. 5 means 5s, 0.5 means 500ms)
+func (d *Duration) UnmarshalJSON(b []byte) error {
+	// Check if it's a string (quoted)
+	if len(b) > 0 && b[0] == '"' {
+		var s string
+		if err := json.Unmarshal(b, &s); err != nil {
+			return err
+		}
+		var err error
+		d.Duration, err = time.ParseDuration(s)
+		return err
+	}
+
+	// Otherwise it's a number — interpret as seconds for human-friendly config
+	var v float64
+	if err := json.Unmarshal(b, &v); err != nil {
+		return err
+	}
+	d.Duration = time.Duration(v * float64(time.Second))
+	return nil
+}
+
+// MarshalJSON converts a duration to JSON.
+func (d Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(d.Duration.String())
+}
+
+// DefaultConfig returns the default swarm configuration.
+func DefaultConfig() *Config {
+	return &Config{
+		Enabled: false,
+		NodeID:  "",
+		Discovery: DiscoveryConfig{
+			NATSURL:           DefaultNATSURL,
+			HeartbeatInterval: Duration{DefaultHeartbeatInterval},
+			MemberTTL:         Duration{DefaultMemberTTL},
+			NodeTimeout:       Duration{DefaultNodeTimeout},
+			DeadNodeTimeout:   Duration{DefaultDeadNodeTimeout},
+		},
+		Handoff: HandoffConfig{
+			Enabled:           true,
+			LoadThreshold:     DefaultLoadThreshold,
+			Timeout:           Duration{DefaultHandoffTimeout},
+			MaxRetries:        DefaultMaxHandoffRetries,
+			RetryDelay:        Duration{DefaultHandoffRetryDelay},
+			RequestTimeout:    Duration{DefaultHandoffRequestTimeout},
+			MaxSessionHistory: DefaultMaxSessionHistory,
+		},
+		LoadMonitor: LoadMonitorConfig{
+			Enabled:                true,
+			Interval:               Duration{DefaultLoadSampleInterval},
+			SampleSize:             DefaultLoadSampleSize,
+			CPUWeight:              DefaultCPUWeight,
+			MemoryWeight:           DefaultMemoryWeight,
+			SessionWeight:          DefaultSessionWeight,
+			OffloadThreshold:       DefaultOffloadThreshold,
+			RoutingRejectThreshold: DefaultRoutingRejectThreshold,
+			RoutingAcceptThreshold: DefaultRoutingAcceptThreshold,
+			MaxMemoryBytes:         DefaultMaxMemoryBytes,
+			MaxGoroutines:          DefaultMaxGoroutines,
+			MaxSessions:            DefaultMaxSessions,
+		},
+		LeaderElection: LeaderElectionConfig{
+			Enabled:         false,
+			LockTTL:         Duration{DefaultLeaderLockTTL},
+			RenewalInterval: Duration{DefaultLeaderRenewalInterval},
+		},
+		Metrics: MetricsConfig{
+			Enabled:            false,
+			ExportInterval:     Duration{10 * time.Second},
+			PrometheusEnabled:  false,
+			PrometheusEndpoint: "/metrics",
+		},
+	}
+}

pkg/swarm/constants.go

@@ -0,0 +1,199 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import "time"
+
+// LoadTrend represents the direction of load change over time.
+type LoadTrend string
+
+const (
+	LoadTrendIncreasing LoadTrend = "increasing"
+	LoadTrendDecreasing LoadTrend = "decreasing"
+	LoadTrendStable     LoadTrend = "stable"
+)
+
+// NATS Subject namespace.
+// All swarm communication uses these subject prefixes.
+// ACL rule: only swarm node identities may publish/subscribe picoclaw.swarm.*
+const (
+	// SubjectPrefix is the root namespace for all swarm subjects.
+	SubjectPrefix = "picoclaw.swarm"
+
+	// SubjectHeartbeat is the prefix for heartbeat messages: picoclaw.swarm.heartbeat.<nodeID>
+	SubjectHeartbeat = SubjectPrefix + ".heartbeat"
+
+	// SubjectMetrics is the prefix for metrics messages: picoclaw.swarm.metrics.<nodeID>
+	SubjectMetrics = SubjectPrefix + ".metrics"
+
+	// SubjectNodeMsg is the prefix for direct node messages: picoclaw.swarm.node.<nodeID>.msg
+	SubjectNodeMsg = SubjectPrefix + ".node"
+
+	// SubjectHandoff is the prefix for targeted handoff: picoclaw.swarm.handoff.<targetNodeID>
+	SubjectHandoff = SubjectPrefix + ".handoff"
+
+	// SubjectLeader is the subject for leader election announcements.
+	SubjectLeader = SubjectPrefix + ".leader"
+)
+
+// NATS JetStream KV Bucket names.
+const (
+	// KVBucketMembers stores node membership with TTL-based liveness.
+	KVBucketMembers = "swarm_members"
+
+	// KVBucketStatus stores detailed node status (CPU, memory, tasks, etc.).
+	KVBucketStatus = "swarm_status"
+
+	// KVBucketLeader stores the leader election CAS lock.
+	KVBucketLeader = "swarm_leader"
+)
+
+// Default NATS connection settings.
+const (
+	// DefaultNATSURL is the default NATS server URL.
+	DefaultNATSURL = "nats://localhost:4222"
+
+	// DefaultNATSPrefix is the default prefix for NATS KV buckets.
+	DefaultNATSPrefix = "picoclaw_swarm"
+)
+
+// Default intervals for NATS-based operations.
+const (
+	// DefaultHeartbeatInterval is how often a node renews its KV entry.
+	DefaultHeartbeatInterval = 5 * time.Second
+
+	// DefaultMemberTTL is the TTL for member entries in the KV bucket.
+	DefaultMemberTTL = 15 * time.Second
+
+	// DefaultDetailedStatusInterval is the interval for publishing detailed status.
+	DefaultDetailedStatusInterval = 10 * time.Second
+
+	// DefaultDetailedStatusTTL is the TTL for detailed status entries.
+	DefaultDetailedStatusTTL = 30 * time.Second
+
+	// DefaultLeaderLockTTL is how long the leader lock lives without renewal.
+	DefaultLeaderLockTTL = 10 * time.Second
+
+	// DefaultLeaderRenewalInterval is how often the leader renews its lock.
+	// Must be less than DefaultLeaderLockTTL.
+	DefaultLeaderRenewalInterval = 3 * time.Second
+
+	// DefaultHandoffRequestTimeout is the timeout for a single NATS handoff request-reply.
+	DefaultHandoffRequestTimeout = 10 * time.Second
+)
+
+// Default timeouts for node health.
+const (
+	// DefaultNodeTimeout is the timeout before marking a node as suspect.
+	DefaultNodeTimeout = 5 * time.Second
+
+	// DefaultDeadNodeTimeout is the timeout before removing a dead node.
+	DefaultDeadNodeTimeout = 30 * time.Second
+)
+
+// Default handoff settings.
+const (
+	// DefaultHandoffTimeout is the default timeout for a handoff operation.
+	DefaultHandoffTimeout = 30 * time.Second
+
+	// DefaultHandoffRetryDelay is the default delay between handoff retries.
+	DefaultHandoffRetryDelay = 5 * time.Second
+
+	// DefaultMaxHandoffRetries is the default maximum number of handoff retries.
+	DefaultMaxHandoffRetries = 3
+
+	// DefaultMaxHandoffPayloadBytes is the max size of a handoff NATS message.
+	// NATS default max_payload is 1MB; we leave headroom for envelope overhead.
+	DefaultMaxHandoffPayloadBytes = 900 * 1024 // 900KB
+)
+
+// Default load monitor settings.
+const (
+	// DefaultLoadSampleInterval is the default interval between load samples.
+	DefaultLoadSampleInterval = 5 * time.Second
+
+	// DefaultLoadSampleSize is the default number of load samples to keep.
+	DefaultLoadSampleSize = 60
+)
+
+// Load thresholds and limits.
+const (
+	// DefaultLoadThreshold is the default load score threshold for handoff.
+	DefaultLoadThreshold = 0.8
+
+	// DefaultAvailableLoadThreshold is the threshold below which a node is considered available (0-1).
+	DefaultAvailableLoadThreshold = 0.9
+
+	// DefaultOffloadThreshold is the default threshold above which tasks should be offloaded (0-1).
+	DefaultOffloadThreshold = 0.8
+
+	// DefaultRoutingRejectThreshold is the load threshold above which routing requests are rejected.
+	// Provides hysteresis to prevent oscillation. Default: 0.9
+	DefaultRoutingRejectThreshold = 0.9
+
+	// DefaultRoutingAcceptThreshold is the load threshold below which routing requests are accepted.
+	// Once rejected, load must drop below this to accept again. Default: 0.75
+	DefaultRoutingAcceptThreshold = 0.75
+
+	// DefaultMaxMemoryBytes is the default max memory for normalization (1GB).
+	DefaultMaxMemoryBytes = 1024 * 1024 * 1024
+
+	// DefaultMaxGoroutines is the default max goroutine count for normalization.
+	DefaultMaxGoroutines = 1000
+
+	// DefaultMaxSessions is the default max session count for normalization.
+	DefaultMaxSessions = 100
+
+	// DefaultMaxSessionHistory is the default number of recent messages to include in handoff.
+	DefaultMaxSessionHistory = 10
+)
+
+// Load score weights.
+const (
+	// DefaultCPUWeight is the default weight for CPU in load score calculation.
+	DefaultCPUWeight = 0.3
+
+	// DefaultMemoryWeight is the default weight for memory in load score calculation.
+	DefaultMemoryWeight = 0.3
+
+	// DefaultSessionWeight is the default weight for sessions in load score calculation.
+	DefaultSessionWeight = 0.4
+)
+
+// Node action constants for action-based node requests.
+// These are lightweight operations that don't trigger LLM processing.
+const (
+	// NodeActionStatus requests node status information.
+	NodeActionStatus = "status"
+
+	// NodeActionPing checks if the node is responsive.
+	NodeActionPing = "ping"
+
+	// NodeActionHealth checks node health metrics.
+	NodeActionHealth = "health"
+
+	// NodeActionLeader queries current leader in leader election.
+	NodeActionLeader = "leader"
+
+	// NodeActionMetrics requests detailed metrics.
+	NodeActionMetrics = "metrics"
+)
+
+// Default timeout for action-based requests (shorter than message processing).
+const (
+	// DefaultNodeActionTimeout is the timeout for lightweight node actions.
+	DefaultNodeActionTimeout = 10 * time.Second
+)
+
+// Trend analysis thresholds.
+const (
+	// TrendIncreasingThreshold is the slope threshold for detecting increasing trend.
+	TrendIncreasingThreshold = 0.01
+
+	// TrendDecreasingThreshold is the slope threshold for detecting decreasing trend.
+	TrendDecreasingThreshold = -0.01
+)

pkg/swarm/coordinator.go

@@ -0,0 +1,64 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"fmt"
+)
+
+// CoordinatorAdapter adapts LeaderElection to the Coordinator interface.
+type CoordinatorAdapter struct {
+	le *LeaderElection
+}
+
+// NewCoordinatorAdapter creates a coordinator adapter from a BucketSet.
+func NewCoordinatorAdapter(
+	buckets *BucketSet,
+	nodeID string,
+	config LeaderElectionConfig,
+) (*CoordinatorAdapter, error) {
+	if buckets == nil {
+		return nil, fmt.Errorf("buckets cannot be nil")
+	}
+
+	le, err := NewLeaderElection(nodeID, buckets.Leader, config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create leader election: %w", err)
+	}
+
+	return &CoordinatorAdapter{le: le}, nil
+}
+
+// Start starts the coordinator.
+func (ca *CoordinatorAdapter) Start() error {
+	return ca.le.Start()
+}
+
+// Stop stops the coordinator.
+func (ca *CoordinatorAdapter) Stop() {
+	ca.le.Stop()
+}
+
+// IsLeader returns true if this node is the current leader.
+func (ca *CoordinatorAdapter) IsLeader() bool {
+	return ca.le.IsLeader()
+}
+
+// LeaderID returns the current leader's node ID.
+func (ca *CoordinatorAdapter) LeaderID() string {
+	return ca.le.GetLeader()
+}
+
+// LeaderChanges returns a channel that receives leader ID changes.
+func (ca *CoordinatorAdapter) LeaderChanges() <-chan string {
+	return ca.le.LeaderChanges()
+}
+
+// GetLeaderElection returns the underlying LeaderElection for advanced usage.
+func (ca *CoordinatorAdapter) GetLeaderElection() *LeaderElection {
+	return ca.le
+}

pkg/swarm/coordinator_interface.go

@@ -0,0 +1,30 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+// Coordinator provides leader election functionality.
+//
+// The coordinator ensures exactly one node in the cluster acts as leader
+// for operations that require cluster-wide coordination.
+type Coordinator interface {
+	// Start starts the coordinator.
+	Start() error
+
+	// Stop stops the coordinator.
+	Stop()
+
+	// IsLeader returns true if this node is the current leader.
+	IsLeader() bool
+
+	// LeaderID returns the current leader's node ID.
+	// Returns empty string if no leader is elected.
+	LeaderID() string
+
+	// LeaderChanges returns a channel that receives leader ID changes.
+	// The channel is closed when Stop() is called.
+	LeaderChanges() <-chan string
+}

pkg/swarm/crypto.go

@@ -0,0 +1,276 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm cryptographic utilities for secure inter-node communication
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// Signer creates and verifies HMAC-SHA256 signatures.
+type Signer struct {
+	secret  []byte
+	enabled bool
+}
+
+// NewSigner creates a new HMAC signer.
+func NewSigner(secret string) *Signer {
+	s := &Signer{enabled: secret != ""}
+	if s.enabled {
+		// Support both base64-encoded and raw secrets
+		if decoded, err := base64.StdEncoding.DecodeString(secret); err == nil && len(decoded) > 0 {
+			s.secret = decoded
+		} else {
+			s.secret = []byte(secret)
+		}
+	}
+	return s
+}
+
+// Sign computes HMAC-SHA256 of the canonical JSON representation of data.
+func (s *Signer) Sign(data any) (string, error) {
+	if !s.enabled {
+		return "", nil
+	}
+
+	// Create canonical JSON (sorted keys)
+	canonical, err := canonicalJSON(data)
+	if err != nil {
+		return "", fmt.Errorf("failed to canonicalize: %w", err)
+	}
+
+	h := hmac.New(sha256.New, s.secret)
+	h.Write(canonical)
+	sig := h.Sum(nil)
+	return base64.StdEncoding.EncodeToString(sig), nil
+}
+
+// Verify verifies the HMAC-SHA256 signature of data.
+func (s *Signer) Verify(data any, signature string) bool {
+	if !s.enabled {
+		return true // Disabled means accept all
+	}
+
+	if signature == "" {
+		return false
+	}
+
+	expected, err := s.Sign(data)
+	if err != nil {
+		return false
+	}
+
+	return hmac.Equal([]byte(signature), []byte(expected))
+}
+
+// Encryptor encrypts/decrypts session data using AES-GCM.
+type Encryptor struct {
+	key     []byte
+	enabled bool
+}
+
+// NewEncryptor creates a new AES-GCM encryptor.
+func NewEncryptor(key string) (*Encryptor, error) {
+	if key == "" {
+		return &Encryptor{enabled: false}, nil
+	}
+
+	// Support both base64-encoded and raw keys
+	var keyBytes []byte
+	if decoded, err := base64.StdEncoding.DecodeString(key); err == nil && len(decoded) > 0 {
+		keyBytes = decoded
+	} else {
+		keyBytes = []byte(key)
+	}
+
+	// AES-256 requires 32-byte key
+	if len(keyBytes) != 32 {
+		return nil, fmt.Errorf("encryption key must be 32 bytes for AES-256, got %d bytes", len(keyBytes))
+	}
+
+	return &Encryptor{
+		key:     keyBytes,
+		enabled: true,
+	}, nil
+}
+
+// EncryptedData wraps encrypted content with nonce.
+type EncryptedData struct {
+	Nonce  string `json:"nonce"`
+	Cipher string `json:"cipher"`
+}
+
+// Encrypt encrypts the provided data using AES-GCM.
+func (e *Encryptor) Encrypt(data []byte) (*EncryptedData, error) {
+	if !e.enabled {
+		return nil, nil
+	}
+
+	block, err := aes.NewCipher(e.key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create cipher: %w", err)
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create GCM: %w", err)
+	}
+
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, fmt.Errorf("failed to generate nonce: %w", err)
+	}
+
+	cipherText := gcm.Seal(nonce, nonce, data, nil)
+
+	return &EncryptedData{
+		Nonce:  base64.StdEncoding.EncodeToString(nonce),
+		Cipher: base64.StdEncoding.EncodeToString(cipherText),
+	}, nil
+}
+
+// Decrypt decrypts the provided data using AES-GCM.
+func (e *Encryptor) Decrypt(enc *EncryptedData) ([]byte, error) {
+	if !e.enabled || enc == nil {
+		return nil, nil
+	}
+
+	nonce, err := base64.StdEncoding.DecodeString(enc.Nonce)
+	if err != nil {
+		return nil, fmt.Errorf("invalid nonce encoding: %w", err)
+	}
+
+	cipherText, err := base64.StdEncoding.DecodeString(enc.Cipher)
+	if err != nil {
+		return nil, fmt.Errorf("invalid cipher encoding: %w", err)
+	}
+
+	block, err := aes.NewCipher(e.key)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create cipher: %w", err)
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create GCM: %w", err)
+	}
+
+	if len(cipherText) < gcm.NonceSize() {
+		return nil, fmt.Errorf("cipher text too short")
+	}
+
+	plaintext, err := gcm.Open(nil, nonce, cipherText, nil)
+	if err != nil {
+		return nil, fmt.Errorf("decryption failed: %w", err)
+	}
+
+	return plaintext, nil
+}
+
+// canonicalJSON creates a canonical JSON representation with sorted keys.
+func canonicalJSON(data any) ([]byte, error) {
+	// Marshal to JSON then unmarshal into map[string]any for sorting
+	j, err := json.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+
+	var raw map[string]any
+	if json.Unmarshal(j, &raw) == nil {
+		// Successfully parsed as object, sort keys
+		return json.Marshal(sortMap(raw))
+	}
+
+	// Not an object, return as-is
+	return j, nil
+}
+
+func sortMap(m map[string]any) map[string]any {
+	sorted := make(map[string]any)
+	for k, v := range m {
+		switch val := v.(type) {
+		case map[string]any:
+			sorted[k] = sortMap(val)
+		case []any:
+			sorted[k] = sortSlice(val)
+		default:
+			sorted[k] = v
+		}
+	}
+	return sorted
+}
+
+func sortSlice(s []any) []any {
+	sorted := make([]any, len(s))
+	for i, v := range s {
+		switch val := v.(type) {
+		case map[string]any:
+			sorted[i] = sortMap(val)
+		case []any:
+			sorted[i] = sortSlice(val)
+		default:
+			sorted[i] = v
+		}
+	}
+	return sorted
+}
+
+// GenerateKey generates a random 32-byte key for AES-256 encryption.
+func GenerateKey() (string, error) {
+	key := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, key); err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(key), nil
+}
+
+// GenerateSecret generates a random HMAC secret.
+func GenerateSecret() (string, error) {
+	secret := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, secret); err != nil {
+		return "", err
+	}
+	return base64.StdEncoding.EncodeToString(secret), nil
+}
+
+// NormalizeKey ensures a key is exactly 32 bytes by hashing or truncating.
+func NormalizeKey(key string) string {
+	if len(key) >= 32 {
+		return key[:32]
+	}
+	h := sha256.Sum256([]byte(key))
+	return string(h[:])
+}
+
+// ComputeMessageSignature creates a signature from key components for manual signing.
+func ComputeMessageSignature(secret string, parts ...string) string {
+	var s strings.Builder
+	for i, p := range parts {
+		if i > 0 {
+			s.WriteByte('|')
+		}
+		s.WriteString(p)
+	}
+
+	h := hmac.New(sha256.New, []byte(secret))
+	h.Write([]byte(s.String()))
+	return base64.StdEncoding.EncodeToString(h.Sum(nil))
+}
+
+// VerifyMessageSignature verifies a manually created signature.
+func VerifyMessageSignature(secret, signature string, parts ...string) bool {
+	expected := ComputeMessageSignature(secret, parts...)
+	return hmac.Equal([]byte(signature), []byte(expected))
+}

pkg/swarm/discovery_adapter.go

@@ -0,0 +1,143 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"sync"
+	"time"
+)
+
+// DiscoveryAdapter adapts the existing DiscoveryService to the NodeDiscovery interface.
+type DiscoveryAdapter struct {
+	ds         Discovery
+	watchers   []func(View)
+	watcherIDs []int // Track watcher IDs for removal
+	nextID     int
+	mu         sync.RWMutex
+	cancel     chan struct{}
+}
+
+// NewDiscoveryAdapter creates a new discovery adapter.
+func NewDiscoveryAdapter(ds Discovery) *DiscoveryAdapter {
+	da := &DiscoveryAdapter{
+		ds:         ds,
+		watchers:   make([]func(View), 0),
+		watcherIDs: make([]int, 0),
+		nextID:     1,
+		cancel:     make(chan struct{}),
+	}
+
+	// Subscribe to node events to update watchers
+	ds.Subscribe(func(event *NodeEvent) {
+		da.notifyWatchers()
+	})
+
+	return da
+}
+
+// Start starts the discovery service.
+func (da *DiscoveryAdapter) Start() error {
+	return da.ds.Start()
+}
+
+// Stop stops the discovery service.
+func (da *DiscoveryAdapter) Stop() error {
+	close(da.cancel)
+	return da.ds.Stop()
+}
+
+// AliveNodes returns the current list of alive nodes.
+func (da *DiscoveryAdapter) AliveNodes() []*NodeInfo {
+	members := da.ds.Members()
+	result := make([]*NodeInfo, 0)
+	for _, m := range members {
+		if m.State.Status == NodeStatusAlive && m.Node.ID != da.ds.LocalNode().ID {
+			result = append(result, m.Node)
+		}
+	}
+	return result
+}
+
+// WatchNodes registers a callback for cluster view changes.
+func (da *DiscoveryAdapter) WatchNodes(callback func(View)) func() {
+	da.mu.Lock()
+	id := da.nextID
+	da.nextID++
+	da.watchers = append(da.watchers, callback)
+	da.watcherIDs = append(da.watcherIDs, id)
+	da.mu.Unlock()
+
+	// Send initial view
+	callback(da.buildView())
+
+	// Return cancel function
+	closed := false
+	return func() {
+		if closed {
+			return
+		}
+		closed = true
+
+		da.mu.Lock()
+		defer da.mu.Unlock()
+
+		// Find and remove the watcher
+		for i, watcherID := range da.watcherIDs {
+			if watcherID == id {
+				// Remove by swapping with last element
+				lastIdx := len(da.watchers) - 1
+				da.watchers[i] = da.watchers[lastIdx]
+				da.watcherIDs[i] = da.watcherIDs[lastIdx]
+				da.watchers = da.watchers[:lastIdx]
+				da.watcherIDs = da.watcherIDs[:lastIdx]
+				break
+			}
+		}
+	}
+}
+
+// notifyWatchers notifies all registered watchers of view changes.
+func (da *DiscoveryAdapter) notifyWatchers() {
+	view := da.buildView()
+
+	da.mu.RLock()
+	watchers := make([]func(View), len(da.watchers))
+	copy(watchers, da.watchers)
+	da.mu.RUnlock()
+
+	for _, w := range watchers {
+		go func(cb func(View)) {
+			defer func() {
+				if r := recover(); r != nil {
+					// Log panic but don't crash
+				}
+			}()
+			cb(view)
+		}(w)
+	}
+}
+
+// buildView builds a View from the current membership state.
+func (da *DiscoveryAdapter) buildView() View {
+	members := da.ds.Members()
+	nodes := make([]*NodeInfo, 0, len(members))
+	for _, m := range members {
+		nodes = append(nodes, m.Node)
+	}
+
+	return View{
+		Nodes:       nodes,
+		LocalNodeID: da.ds.LocalNode().ID,
+		Version:     time.Now().UnixNano(),
+		Timestamp:   time.Now().UnixNano(),
+	}
+}
+
+// GetDiscovery returns the underlying Discovery service.
+func (da *DiscoveryAdapter) GetDiscovery() Discovery {
+	return da.ds
+}

pkg/swarm/discovery_interface.go

@@ -0,0 +1,74 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import "github.com/nats-io/nats.go"
+
+// Discovery is the interface for node discovery implementations.
+// In the current architecture, NATS is the sole transport.
+//
+//nolint:interfacebloat // Single concrete implementation; splitting would add indirection without benefit.
+type Discovery interface {
+	// Start starts the discovery service.
+	Start() error
+
+	// Stop stops the discovery service.
+	Stop() error
+
+	// LocalNode returns the local node info.
+	LocalNode() *NodeInfo
+
+	// UpdateLocalInfo updates the local node's information.
+	UpdateLocalInfo(info *NodeInfo)
+
+	// UpdateLoad updates the local node's load score.
+	UpdateLoad(score float64)
+
+	// UpdateCapabilities updates the local node's agent capabilities.
+	UpdateCapabilities(caps map[string]string)
+
+	// Members returns all known members.
+	Members() []*NodeWithState
+
+	// GetNode returns a node by ID.
+	GetNode(nodeID string) (*NodeWithState, bool)
+
+	// Subscribe registers a handler for node events.
+	Subscribe(handler EventHandler) EventHandlerID
+
+	// Unsubscribe removes a node event handler.
+	Unsubscribe(id EventHandlerID)
+
+	// PublishLocalUpdate publishes local node state.
+	PublishLocalUpdate()
+
+	// DispatchEvent dispatches a node event to registered handlers.
+	DispatchEvent(event *NodeEvent)
+
+	// GetMembershipManager returns the membership manager.
+	GetMembershipManager() *MembershipManager
+
+	// NATSConn returns the underlying NATS connection.
+	// Used by handoff, leader election, and messaging subsystems.
+	NATSConn() *nats.Conn
+
+	// JetStream returns the JetStream context.
+	// Used for KV operations (membership, leader election).
+	JetStream() nats.JetStreamContext
+
+	// Buckets returns the KV bucket set.
+	// Used for leader election and other distributed state operations.
+	Buckets() *BucketSet
+}
+
+// DetailedStatusProvider is an optional capability interface for discovery
+// implementations that maintain a local cache of detailed node status.
+// Tools should use this interface via type assertion instead of depending
+// on a concrete discovery type.
+type DetailedStatusProvider interface {
+	GetDetailedStatus() *NodeDetailedStatus
+}

pkg/swarm/discovery_nats.go

@@ -0,0 +1,456 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"github.com/sipeed/picoclaw/pkg/kv"
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// DiscoveryService implements node discovery using NATS JetStream KeyValue store.
+// This is the sole discovery implementation — all swarm communication goes through NATS.
+type DiscoveryService struct {
+	config       *Config
+	localNode    *NodeInfo
+	membership   *MembershipManager
+	eventHandler *EventDispatcher
+	nc           *nats.Conn
+	js           nats.JetStreamContext
+	buckets      *BucketSet
+
+	detailedStatus *NodeDetailedStatus
+	loadMonitor    *LoadMonitor
+
+	mu       sync.RWMutex
+	running  bool
+	stopChan chan struct{}
+	once     sync.Once
+
+	seqNum      uint64
+	startTime   time.Time
+	todoList    []string
+	activeTasks int
+	lastError   string
+	version     string
+}
+
+// generateStableNodeID generates a stable node ID that persists across restarts.
+// It uses hostname as the base, optionally loading a previously generated ID from a file.
+func generateStableNodeID() string {
+	hostname, _ := os.Hostname()
+	if hostname == "" {
+		hostname = "picoclaw"
+	}
+
+	// Try to load a previously generated stable ID from a file
+	// This ensures the same ID is used across restarts even if hostname changes
+	dataDir := os.Getenv("PICOCLAW_DATA_DIR")
+	if dataDir == "" {
+		// Default to current directory
+		dataDir = "."
+	}
+	nodeIDFile := fmt.Sprintf("%s/.swarm_node_id", dataDir)
+
+	if idBytes, err := os.ReadFile(nodeIDFile); err == nil {
+		storedID := strings.TrimSpace(string(idBytes))
+		if storedID != "" {
+			logger.InfoCF("swarm", "Loaded stable node ID from file", map[string]any{"node_id": storedID})
+			return storedID
+		}
+	}
+
+	// Generate a stable ID based on hostname
+	// Using just hostname ensures stability across restarts
+	// For multiple instances on the same host, users should explicitly set PICOCLAW_SWARM_NODE_ID
+	stableID := hostname
+
+	// Optionally persist this ID for future use
+	_ = os.WriteFile(nodeIDFile, []byte(stableID), 0o644)
+
+	logger.InfoCF("swarm", "Generated stable node ID", map[string]any{
+		"node_id":      stableID,
+		"node_id_file": nodeIDFile,
+		"env_override": "PICOCLAW_SWARM_NODE_ID",
+	})
+	return stableID
+}
+
+// getLocalIP returns the local IP address.
+func getLocalIP() string {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return ""
+	}
+
+	for _, addr := range addrs {
+		if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
+			if ipnet.IP.To4() != nil {
+				return ipnet.IP.String()
+			}
+		}
+	}
+	return ""
+}
+
+// NewDiscoveryService creates a new NATS-based discovery service.
+func NewDiscoveryService(cfg *Config) (*DiscoveryService, error) {
+	if cfg.NodeID == "" {
+		cfg.NodeID = generateStableNodeID()
+		logger.WarnCF(
+			"swarm",
+			"NodeID not configured, using auto-generated stable ID. For production, explicitly set PICOCLAW_SWARM_NODE_ID environment variable",
+			map[string]any{
+				"node_id": cfg.NodeID,
+			},
+		)
+	}
+
+	// Determine advertise address
+	advAddr := getLocalIP()
+	if advAddr == "" {
+		advAddr = "127.0.0.1"
+	}
+
+	localNode := &NodeInfo{
+		ID:        cfg.NodeID,
+		Addr:      advAddr,
+		Port:      0, // No direct RPC port; all communication via NATS
+		AgentCaps: make(map[string]string),
+		LoadScore: 0,
+		Labels:    make(map[string]string),
+		Timestamp: time.Now().UnixNano(),
+		Version:   "1.0.0",
+	}
+
+	ds := &DiscoveryService{
+		config:         cfg,
+		localNode:      localNode,
+		eventHandler:   NewEventDispatcher(),
+		stopChan:       make(chan struct{}),
+		detailedStatus: NewNodeDetailedStatus(),
+		startTime:      time.Now(),
+		todoList:       make([]string, 0),
+		activeTasks:    0,
+		version:        "1.0.0",
+	}
+
+	// Initialize membership manager
+	ds.membership = NewMembershipManager(ds, cfg.Discovery)
+
+	return ds, nil
+}
+
+// buildNATSOptions constructs NATS connection options from config.
+func buildNATSOptions(cfg DiscoveryConfig, nodeID string) []nats.Option {
+	var opts []nats.Option
+
+	opts = append(opts, nats.Name("picoclaw-"+nodeID))
+
+	// NKeys / JWT credentials
+	if cfg.NATSCredsFile != "" {
+		opts = append(opts, nats.UserCredentials(cfg.NATSCredsFile))
+	}
+
+	// mTLS client certificate
+	if cfg.NATSTLSCert != "" && cfg.NATSTLSKey != "" {
+		opts = append(opts, nats.ClientCert(cfg.NATSTLSCert, cfg.NATSTLSKey))
+	}
+
+	// CA certificate for server verification
+	if cfg.NATSTLSCACert != "" {
+		opts = append(opts, nats.RootCAs(cfg.NATSTLSCACert))
+	}
+
+	// Auto-reconnect
+	opts = append(opts, nats.MaxReconnects(-1))
+	opts = append(opts, nats.ReconnectWait(2*time.Second))
+
+	return opts
+}
+
+// Start starts the NATS discovery service.
+func (ds *DiscoveryService) Start() error {
+	ds.mu.Lock()
+	if ds.running {
+		ds.mu.Unlock()
+		return nil
+	}
+	ds.running = true
+	ds.mu.Unlock()
+
+	// Get NATS URL from config or use default
+	natsURL := ds.config.Discovery.NATSURL
+	if natsURL == "" {
+		natsURL = DefaultNATSURL
+	}
+
+	// Build connection options (TLS, creds, reconnect)
+	opts := buildNATSOptions(ds.config.Discovery, ds.config.NodeID)
+
+	// Connect to NATS
+	var err error
+	ds.nc, err = nats.Connect(natsURL, opts...)
+	if err != nil {
+		return fmt.Errorf("failed to connect to NATS: %w", err)
+	}
+
+	// Get JetStream context
+	ds.js, err = ds.nc.JetStream()
+	if err != nil {
+		ds.nc.Close()
+		return fmt.Errorf("failed to get JetStream context: %w", err)
+	}
+
+	// Create bucket factory and initialize buckets
+	factory := kv.NewNATSBucketFactory(ds.js)
+	ds.buckets, err = NewBucketSet(factory)
+	if err != nil {
+		ds.nc.Close()
+		return fmt.Errorf("failed to create buckets: %w", err)
+	}
+
+	logger.InfoCF("swarm", "NATS discovery service started", map[string]any{
+		"nats_url": natsURL,
+		"node_id":  ds.localNode.ID,
+	})
+
+	// Start heartbeat routine
+	go ds.heartbeatLoop()
+
+	// Start detailed status publisher
+	go ds.detailedStatusLoop()
+
+	// Start watch for other nodes
+	go ds.watchNodes()
+
+	// Start watch for detailed status from other nodes
+	go ds.watchDetailedStatus()
+
+	// Add self to membership
+	ds.membership.UpdateNode(ds.localNode)
+
+	return nil
+}
+
+// Stop stops the NATS discovery service.
+func (ds *DiscoveryService) Stop() error {
+	ds.once.Do(func() {
+		ds.mu.Lock()
+		ds.running = false
+		ds.mu.Unlock()
+
+		if ds.stopChan != nil {
+			close(ds.stopChan)
+		}
+
+		// Delete our entry from members bucket
+		if ds.buckets != nil && ds.localNode != nil {
+			_ = ds.buckets.Members.Delete(ds.localNode.ID)
+		}
+
+		// Close buckets
+		if ds.buckets != nil {
+			_ = ds.buckets.Close()
+		}
+
+		if ds.nc != nil {
+			ds.nc.Close()
+		}
+	})
+	return nil
+}
+
+// LocalNode returns the local node info.
+func (ds *DiscoveryService) LocalNode() *NodeInfo {
+	ds.mu.RLock()
+	defer ds.mu.RUnlock()
+	return ds.localNode
+}
+
+// UpdateLocalInfo updates the local node's information.
+func (ds *DiscoveryService) UpdateLocalInfo(info *NodeInfo) {
+	ds.mu.Lock()
+	ds.localNode = info
+	ds.localNode.Timestamp = time.Now().UnixNano()
+	ds.seqNum++
+	info = ds.localNode
+	ds.mu.Unlock()
+
+	ds.membership.UpdateNode(info)
+	ds.publishNode()
+}
+
+// UpdateLoad updates the local node's load score.
+func (ds *DiscoveryService) UpdateLoad(score float64) {
+	ds.mu.Lock()
+	ds.localNode.LoadScore = score
+	ds.localNode.Timestamp = time.Now().UnixNano()
+	ds.seqNum++
+	info := ds.localNode
+	ds.mu.Unlock()
+
+	ds.membership.UpdateNode(info)
+	ds.publishNode()
+}
+
+// UpdateCapabilities updates the local node's agent capabilities.
+func (ds *DiscoveryService) UpdateCapabilities(caps map[string]string) {
+	ds.mu.Lock()
+	ds.localNode.AgentCaps = caps
+	ds.localNode.Timestamp = time.Now().UnixNano()
+	ds.seqNum++
+	info := ds.localNode
+	ds.mu.Unlock()
+
+	ds.membership.UpdateNode(info)
+	ds.publishNode()
+}
+
+// Members returns all known members.
+func (ds *DiscoveryService) Members() []*NodeWithState {
+	return ds.membership.GetMembers()
+}
+
+// GetNode returns a node by ID.
+func (ds *DiscoveryService) GetNode(nodeID string) (*NodeWithState, bool) {
+	return ds.membership.GetNode(nodeID)
+}
+
+// Subscribe registers a handler for node events.
+func (ds *DiscoveryService) Subscribe(handler EventHandler) EventHandlerID {
+	return ds.eventHandler.Subscribe(handler)
+}
+
+// Unsubscribe removes a node event handler.
+func (ds *DiscoveryService) Unsubscribe(id EventHandlerID) {
+	ds.eventHandler.Unsubscribe(id)
+}
+
+// PublishLocalUpdate publishes local node state.
+func (ds *DiscoveryService) PublishLocalUpdate() {
+	ds.publishNode()
+}
+
+// DispatchEvent dispatches a node event to registered handlers.
+func (ds *DiscoveryService) DispatchEvent(event *NodeEvent) {
+	ds.eventHandler.Dispatch(event)
+}
+
+// GetMembershipManager returns the membership manager.
+func (ds *DiscoveryService) GetMembershipManager() *MembershipManager {
+	return ds.membership
+}
+
+// NATSConn returns the underlying NATS connection.
+func (ds *DiscoveryService) NATSConn() *nats.Conn {
+	return ds.nc
+}
+
+// JetStream returns the JetStream context.
+func (ds *DiscoveryService) JetStream() nats.JetStreamContext {
+	return ds.js
+}
+
+// Buckets returns the bucket set.
+func (ds *DiscoveryService) Buckets() *BucketSet {
+	return ds.buckets
+}
+
+// Helper methods for todo list, active tasks, and error tracking.
+
+// getTodoList returns the current todo list.
+func (ds *DiscoveryService) getTodoList() []string {
+	ds.mu.RLock()
+	defer ds.mu.RUnlock()
+	return ds.todoList
+}
+
+// SetTodoList sets the todo list for detailed status reporting.
+func (ds *DiscoveryService) SetTodoList(todos []string) {
+	ds.mu.Lock()
+	ds.todoList = todos
+	ds.mu.Unlock()
+}
+
+// AddTodo adds a todo item to the todo list.
+func (ds *DiscoveryService) AddTodo(todo string) {
+	ds.mu.Lock()
+	defer ds.mu.Unlock()
+	ds.todoList = append(ds.todoList, todo)
+}
+
+// RemoveTodo removes a todo item from the todo list.
+func (ds *DiscoveryService) RemoveTodo(todo string) {
+	ds.mu.Lock()
+	defer ds.mu.Unlock()
+	for i, t := range ds.todoList {
+		if t == todo {
+			ds.todoList = append(ds.todoList[:i], ds.todoList[i+1:]...)
+			break
+		}
+	}
+}
+
+// ClearTodoList clears the todo list.
+func (ds *DiscoveryService) ClearTodoList() {
+	ds.mu.Lock()
+	ds.todoList = make([]string, 0)
+	ds.mu.Unlock()
+}
+
+// getActiveTasks returns the current active tasks count.
+func (ds *DiscoveryService) getActiveTasks() int {
+	ds.mu.RLock()
+	defer ds.mu.RUnlock()
+	return ds.activeTasks
+}
+
+// SetActiveTasks sets the active tasks count.
+func (ds *DiscoveryService) SetActiveTasks(count int) {
+	ds.mu.Lock()
+	ds.activeTasks = count
+	ds.mu.Unlock()
+}
+
+// IncrementActiveTasks increments the active tasks count.
+func (ds *DiscoveryService) IncrementActiveTasks() {
+	ds.mu.Lock()
+	ds.activeTasks++
+	ds.mu.Unlock()
+}
+
+// DecrementActiveTasks decrements the active tasks count.
+func (ds *DiscoveryService) DecrementActiveTasks() {
+	ds.mu.Lock()
+	if ds.activeTasks > 0 {
+		ds.activeTasks--
+	}
+	ds.mu.Unlock()
+}
+
+// getLastError returns the last error.
+func (ds *DiscoveryService) getLastError() string {
+	ds.mu.RLock()
+	defer ds.mu.RUnlock()
+	return ds.lastError
+}
+
+// SetLastError sets the last error for detailed status reporting.
+func (ds *DiscoveryService) SetLastError(err string) {
+	ds.mu.Lock()
+	ds.lastError = err
+	ds.mu.Unlock()
+}

pkg/swarm/errors.go

@@ -0,0 +1,81 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import "errors"
+
+var (
+	// ErrNodeNotFound is returned when a node is not found in the cluster.
+	ErrNodeNotFound = errors.New("node not found")
+
+	// ErrNodeNotAvailable is returned when a node is not available for handoff.
+	ErrNodeNotAvailable = errors.New("node not available")
+
+	// ErrNoHealthyNodes is returned when no healthy nodes are available.
+	ErrNoHealthyNodes = errors.New("no healthy nodes available")
+
+	// ErrHandoffTimeout is returned when a handoff operation times out.
+	ErrHandoffTimeout = errors.New("handoff timeout")
+
+	// ErrHandoffRejected is returned when a handoff is rejected by the target node.
+	ErrHandoffRejected = errors.New("handoff rejected")
+
+	// ErrHandoffInProgress is returned when a handoff is already in progress.
+	ErrHandoffInProgress = errors.New("handoff already in progress")
+
+	// ErrHandoffNoResponders is returned when no nodes responded to a handoff request.
+	ErrHandoffNoResponders = errors.New("no nodes responded to handoff request")
+
+	// ErrInvalidNodeInfo is returned when node information is invalid.
+	ErrInvalidNodeInfo = errors.New("invalid node information")
+
+	// ErrDiscoveryDisabled is returned when discovery is disabled.
+	ErrDiscoveryDisabled = errors.New("discovery disabled")
+
+	// ErrSessionNotFound is returned when a session is not found.
+	ErrSessionNotFound = errors.New("session not found")
+
+	// ErrCapabilityNotSupported is returned when a required capability is not supported.
+	ErrCapabilityNotSupported = errors.New("capability not supported")
+
+	// ErrNATSNotConnected is returned when the NATS connection is not established.
+	ErrNATSNotConnected = errors.New("NATS not connected")
+
+	// ErrLeaderLockFailed is returned when leader lock acquisition fails.
+	ErrLeaderLockFailed = errors.New("leader lock acquisition failed")
+
+	// ErrLeaderLockLost is returned when the leader lock is lost (CAS renewal failed).
+	ErrLeaderLockLost = errors.New("leader lock lost")
+
+	// ErrKVBucketUnavailable is returned when a required KV bucket cannot be accessed.
+	ErrKVBucketUnavailable = errors.New("KV bucket unavailable")
+)
+
+// IsBusinessRejection returns true if the error represents a legitimate business rejection
+// (e.g., no nodes available, node overloaded) rather than a system failure.
+// Business rejections should be communicated via HandoffResponse.Accepted=false.
+// System failures should be returned as Go errors for proper handling.
+func IsBusinessRejection(err error) bool {
+	if err == nil {
+		return false
+	}
+	return err == ErrNoHealthyNodes ||
+		err == ErrNodeNotAvailable ||
+		err == ErrHandoffRejected ||
+		err == ErrHandoffInProgress ||
+		err == ErrCapabilityNotSupported
+}
+
+// IsSystemError returns true if the error represents a system failure
+// (e.g., NATS unavailable, timeout, serialization failure).
+// System errors should propagate up the call stack as Go errors.
+func IsSystemError(err error) bool {
+	if err == nil {
+		return false
+	}
+	return !IsBusinessRejection(err)
+}

pkg/swarm/handoff.go

@@ -0,0 +1,956 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/nats-io/nats.go"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// HandoffReason represents the reason for a handoff.
+type HandoffReason string
+
+const (
+	ReasonOverloaded   HandoffReason = "overloaded"    // Load is too high
+	ReasonNoCapability HandoffReason = "no_capability" // Missing capability
+	ReasonUserRequest  HandoffReason = "user_request"  // User explicitly requested
+	ReasonNodeLeave    HandoffReason = "node_leave"    // Node is leaving
+	ReasonShutdown     HandoffReason = "shutdown"      // Graceful shutdown
+)
+
+// HandoffState represents the state of a handoff operation.
+type HandoffState string
+
+const (
+	HandoffStatePending   HandoffState = "pending"
+	HandoffStateAccepted  HandoffState = "accepted"
+	HandoffStateRejected  HandoffState = "rejected"
+	HandoffStateCompleted HandoffState = "completed"
+	HandoffStateFailed    HandoffState = "failed"
+	HandoffStateTimeout   HandoffState = "timeout"
+	HandoffStateDuplicate HandoffState = "duplicate" // Replay attack detected
+	HandoffStateExpired   HandoffState = "expired"   // Timestamp outside valid window
+)
+
+// Security constants for replay attack prevention.
+const (
+	// DefaultTimestampWindow is the acceptable timestamp skew (±60 seconds).
+	DefaultTimestampWindow = 60 * time.Second
+
+	// DefaultNonceTTL is how long nonces are kept in cache.
+	DefaultNonceTTL = 5 * time.Minute
+
+	// DefaultNonceCacheSize is the ring buffer size for nonce tracking.
+	DefaultNonceCacheSize = 1000
+)
+
+// SessionMessage represents a message in a session (local type replacing picolib.SessionMessage).
+type SessionMessage struct {
+	Role    string `json:"role"`
+	Content string `json:"content"`
+}
+
+// HandoffRequest represents a request to hand off a session.
+type HandoffRequest struct {
+	// Core identification
+	RequestID string `json:"request_id"` // Unique handoff ID for idempotency
+
+	// Handoff details
+	Reason          HandoffReason     `json:"reason"`
+	SessionKey      string            `json:"session_key"`
+	SessionMessages []SessionMessage  `json:"session_messages,omitempty"`
+	Context         map[string]any    `json:"context,omitempty"`
+	RequiredCap     string            `json:"required_cap,omitempty"`
+	Metadata        map[string]string `json:"metadata,omitempty"`
+
+	// Routing information
+	FromNodeID   string `json:"from_node_id"`
+	FromNodeAddr string `json:"from_node_addr"`
+	TargetNodeID string `json:"target_node_id,omitempty"`
+
+	// Timestamp for replay protection (Unix nanoseconds)
+	Timestamp int64 `json:"timestamp"`
+
+	// Security fields
+	Nonce         string         `json:"nonce,omitempty"`     // Unique value for replay protection
+	Signature     string         `json:"signature,omitempty"` // HMAC-SHA256 signature
+	EncryptedData *EncryptedData `json:"encrypted,omitempty"` // AES-GCM encrypted session/context
+}
+
+// signingPayload returns the canonical payload for signature calculation.
+// Covers all routing fields to prevent message redirection attacks.
+func (r *HandoffRequest) signingPayload() map[string]any {
+	// Include payload hash for large payloads
+	payloadHash := ""
+	if len(r.SessionMessages) > 0 || len(r.Context) > 0 {
+		payloadData := map[string]any{
+			"session_messages": r.SessionMessages,
+			"context":          r.Context,
+		}
+		if j, err := json.Marshal(payloadData); err == nil {
+			hash := sha256.Sum256(j)
+			payloadHash = fmt.Sprintf("%x", hash)[:16]
+		}
+	}
+
+	return map[string]any{
+		"request_id":   r.RequestID,
+		"nonce":        r.Nonce,
+		"from_node_id": r.FromNodeID,
+		"to_node_id":   r.TargetNodeID, // Prevents redirection attacks
+		"session_key":  r.SessionKey,
+		"required_cap": r.RequiredCap,
+		"timestamp":    r.Timestamp,
+		"payload_hash": payloadHash,
+	}
+}
+
+// HandoffResponse represents the response to a handoff request.
+type HandoffResponse struct {
+	RequestID  string       `json:"request_id"`
+	Accepted   bool         `json:"accepted"`
+	NodeID     string       `json:"node_id"`
+	Reason     string       `json:"reason,omitempty"`
+	SessionKey string       `json:"session_key,omitempty"` // New session key on target
+	Timestamp  int64        `json:"timestamp"`
+	State      HandoffState `json:"state"`
+
+	// TruncationInfo indicates if session history was truncated during handoff.
+	TruncationInfo *TruncationInfo `json:"truncation_info,omitempty"`
+}
+
+// TruncationInfo contains details about message truncation.
+type TruncationInfo struct {
+	OriginalCount  int `json:"original_count"`
+	RemainingCount int `json:"remaining_count"`
+	BytesRemoved   int `json:"bytes_removed"`
+}
+
+// HandoffCoordinator coordinates handoff operations between nodes via NATS request-reply.
+//
+// Each node subscribes to its own targeted handoff subject:
+//
+//	picoclaw.swarm.handoff.<localNodeID>
+//
+// When initiating a handoff, the coordinator sends a NATS request to the target node's
+// handoff subject and waits for a synchronous reply.
+type HandoffCoordinator struct {
+	discovery  Discovery
+	membership *MembershipManager
+	config     HandoffConfig
+	nc         *nats.Conn
+
+	pending map[string]*HandoffOperation // request_id -> operation
+	mu      sync.RWMutex
+
+	sub *nats.Subscription // Subscription for incoming handoff requests
+
+	// Security
+	signer          *Signer
+	encryptor       *Encryptor
+	cryptoConfig    CryptoConfig
+	nonceCache      *NonceCache
+	timestampWindow time.Duration
+
+	// Idempotency: track processed handoff IDs
+	processed   map[string]*HandoffResponse // request_id -> cached response
+	processedMu sync.RWMutex
+
+	// Failure policies
+	circuitBreaker *CircuitBreaker
+	nodeCooldown   *NodeCooldown
+	failurePolicy  FailurePolicy
+
+	// Accept/reject callbacks
+	onHandoffRequest  func(*HandoffRequest) *HandoffResponse
+	onHandoffComplete func(*HandoffRequest, *HandoffResponse)
+
+	// Metrics
+	metrics *HandoffMetrics
+}
+
+// HandoffOperation represents an ongoing handoff operation.
+type HandoffOperation struct {
+	Request    *HandoffRequest
+	Response   *HandoffResponse
+	State      HandoffState
+	StartTime  time.Time
+	LastUpdate time.Time
+	RetryCount int
+	TargetNode *NodeWithState
+}
+
+// NewHandoffCoordinator creates a new handoff coordinator.
+func NewHandoffCoordinator(ds Discovery, config HandoffConfig) *HandoffCoordinator {
+	policy := DefaultFailurePolicy()
+	return &HandoffCoordinator{
+		discovery:       ds,
+		membership:      ds.GetMembershipManager(),
+		config:          config,
+		nc:              ds.NATSConn(),
+		pending:         make(map[string]*HandoffOperation),
+		processed:       make(map[string]*HandoffResponse),
+		metrics:         NewHandoffMetrics(),
+		nonceCache:      NewNonceCache(DefaultNonceTTL, DefaultNonceCacheSize),
+		timestampWindow: DefaultTimestampWindow,
+		circuitBreaker:  NewCircuitBreaker(policy.MaxConsecutiveFailures, policy.CircuitBreakerCooldown.Duration),
+		nodeCooldown:    NewNodeCooldown(policy.OverloadCooldown.Duration),
+		failurePolicy:   *policy,
+	}
+}
+
+// SetCryptoConfig configures the cryptographic components for secure handoff.
+// Returns error if RequireAuth or RequireEncryption is enabled without proper credentials.
+func (hc *HandoffCoordinator) SetCryptoConfig(cfg CryptoConfig) error {
+	hc.cryptoConfig = cfg
+	hc.signer = NewSigner(cfg.SharedSecret)
+
+	if cfg.EncryptionKey != "" {
+		enc, err := NewEncryptor(cfg.EncryptionKey)
+		if err != nil {
+			return fmt.Errorf("failed to initialize encryptor: %w", err)
+		}
+		hc.encryptor = enc
+	}
+
+	// Strict validation: error out if auth/encryption required but credentials missing
+	if cfg.RequireAuth && cfg.SharedSecret == "" {
+		return fmt.Errorf("RequireAuth=true but SharedSecret is empty; authentication cannot be enforced")
+	}
+
+	if cfg.RequireEncryption && cfg.EncryptionKey == "" {
+		return fmt.Errorf("RequireEncryption=true but EncryptionKey is empty; encryption cannot be enforced")
+	}
+
+	return nil
+}
+
+// Start begins listening for incoming handoff requests on the targeted NATS subject.
+func (hc *HandoffCoordinator) Start() error {
+	if hc.nc == nil {
+		return ErrNATSNotConnected
+	}
+
+	localNodeID := hc.discovery.LocalNode().ID
+	subject := SubjectHandoff + "." + localNodeID
+
+	var err error
+	hc.sub, err = hc.nc.Subscribe(subject, hc.handleIncomingNATSMsg)
+	if err != nil {
+		return fmt.Errorf("failed to subscribe to handoff subject %s: %w", subject, err)
+	}
+
+	logger.InfoCF("swarm", "Handoff coordinator started", map[string]any{
+		"subject": subject,
+	})
+
+	return nil
+}
+
+// Close cleans up the handoff coordinator.
+func (hc *HandoffCoordinator) Close() error {
+	if hc.sub != nil {
+		return hc.sub.Unsubscribe()
+	}
+	return nil
+}
+
+// handleIncomingNATSMsg handles a NATS message containing a HandoffRequest.
+func (hc *HandoffCoordinator) handleIncomingNATSMsg(msg *nats.Msg) {
+	var req HandoffRequest
+	if err := json.Unmarshal(msg.Data, &req); err != nil {
+		hc.metrics.RecordFailed()
+		logger.ErrorCF("swarm", "Failed to decode handoff request", map[string]any{"error": err})
+		hc.rejectHandoff(msg, "", "invalid_format", "")
+		return
+	}
+
+	// Validate required fields
+	if req.RequestID == "" || req.FromNodeID == "" {
+		hc.metrics.RecordFailed()
+		hc.rejectHandoff(msg, req.RequestID, "missing_required_fields", "")
+		return
+	}
+
+	// Check idempotency: was this handoff already processed?
+	hc.processedMu.RLock()
+	if cachedResp, exists := hc.processed[req.RequestID]; exists {
+		hc.processedMu.RUnlock()
+		logger.InfoCF("swarm", "Returning cached handoff response (duplicate)", map[string]any{
+			"request_id": req.RequestID,
+			"from_node":  req.FromNodeID,
+		})
+		respData, _ := json.Marshal(cachedResp)
+		msg.Respond(respData)
+		return
+	}
+	hc.processedMu.RUnlock()
+
+	now := time.Now()
+
+	// Timestamp validation: check for replay attacks
+	if req.Timestamp > 0 {
+		reqTime := time.Unix(0, req.Timestamp)
+		skew := reqTime.Sub(now)
+
+		// Log clock skew for debugging (even if within window)
+		if skew.Abs() > time.Second {
+			logger.DebugCF("swarm", "Handoff timestamp skew", map[string]any{
+				"skew_ms":   skew.Milliseconds(),
+				"from_node": req.FromNodeID,
+			})
+		}
+
+		if skew.Abs() > hc.timestampWindow {
+			hc.metrics.RecordAuthFailure()
+			logger.WarnCF("swarm", "Handoff request timestamp outside valid window", map[string]any{
+				"skew_seconds":   skew.Seconds(),
+				"window_seconds": hc.timestampWindow.Seconds(),
+				"from_node":      req.FromNodeID,
+				"request_id":     req.RequestID,
+			})
+			resp := &HandoffResponse{
+				RequestID: req.RequestID,
+				Accepted:  false,
+				Reason:    "unauthorized",
+				State:     HandoffStateExpired,
+				Timestamp: now.UnixNano(),
+			}
+			hc.cacheAndRespond(msg, req.RequestID, resp)
+			return
+		}
+	}
+
+	// Nonce validation: check for replay attacks
+	if req.Nonce != "" && hc.cryptoConfig.RequireAuth {
+		if !hc.nonceCache.CheckAndAdd(req.Nonce, req.FromNodeID) {
+			hc.metrics.RecordAuthFailure()
+			logger.WarnCF("swarm", "Handoff request with duplicate nonce rejected (replay attack)", map[string]any{
+				"from_node":  req.FromNodeID,
+				"request_id": req.RequestID,
+			})
+			resp := &HandoffResponse{
+				RequestID: req.RequestID,
+				Accepted:  false,
+				Reason:    "unauthorized",
+				State:     HandoffStateDuplicate,
+				Timestamp: now.UnixNano(),
+			}
+			hc.cacheAndRespond(msg, req.RequestID, resp)
+			return
+		}
+	}
+
+	// Verify signature if authentication is required
+	if hc.signer != nil && hc.cryptoConfig.RequireAuth {
+		if !hc.signer.Verify(req.signingPayload(), req.Signature) {
+			hc.metrics.RecordAuthFailure()
+			logger.WarnCF("swarm", "Handoff request signature verification failed", map[string]any{
+				"from_node":  req.FromNodeID,
+				"request_id": req.RequestID,
+			})
+			resp := &HandoffResponse{
+				RequestID: req.RequestID,
+				Accepted:  false,
+				Reason:    "unauthorized",
+				State:     HandoffStateRejected,
+				Timestamp: now.UnixNano(),
+			}
+			hc.cacheAndRespond(msg, req.RequestID, resp)
+			return
+		}
+	}
+
+	// Don't self-handoff
+	localNodeID := hc.discovery.LocalNode().ID
+	if req.FromNodeID == localNodeID {
+		return
+	}
+
+	// Decrypt session data if encrypted
+	if req.EncryptedData != nil && hc.encryptor != nil {
+		decrypted, err := hc.encryptor.Decrypt(req.EncryptedData)
+		if err != nil {
+			hc.metrics.RecordDecryptError()
+			logger.WarnCF("swarm", "Handoff data decryption failed", map[string]any{
+				"from_node":  req.FromNodeID,
+				"request_id": req.RequestID,
+			})
+			resp := &HandoffResponse{
+				RequestID: req.RequestID,
+				Accepted:  false,
+				Reason:    "unauthorized",
+				State:     HandoffStateRejected,
+				Timestamp: now.UnixNano(),
+			}
+			hc.cacheAndRespond(msg, req.RequestID, resp)
+			return
+		}
+
+		// Unmarshal the decrypted data into a temporary struct to extract session/context
+		var decryptedData struct {
+			SessionMessages []SessionMessage `json:"session_messages"`
+			Context         map[string]any   `json:"context"`
+		}
+		if err := json.Unmarshal(decrypted, &decryptedData); err == nil {
+			req.SessionMessages = decryptedData.SessionMessages
+			req.Context = decryptedData.Context
+		}
+	}
+
+	// Process the request
+	resp := hc.HandleIncomingHandoff(&req)
+	resp.Timestamp = now.UnixNano()
+
+	// Cache response for idempotency
+	hc.cacheAndRespond(msg, req.RequestID, resp)
+}
+
+// rejectHandoff sends a generic rejection response without caching.
+func (hc *HandoffCoordinator) rejectHandoff(msg *nats.Msg, requestID, reason, state string) {
+	resp := &HandoffResponse{
+		RequestID: requestID,
+		Accepted:  false,
+		Reason:    "unauthorized", // Always return generic reason to caller
+		State:     HandoffStateRejected,
+		Timestamp: time.Now().UnixNano(),
+	}
+	if state != "" {
+		resp.State = HandoffState(state)
+	}
+	respData, _ := json.Marshal(resp)
+	msg.Respond(respData)
+
+	// Log the real reason internally
+	logger.DebugCF("swarm", "Handoff rejected", map[string]any{
+		"request_id": requestID,
+		"reason":     reason,
+	})
+}
+
+// cacheAndRespond caches the response and sends it.
+func (hc *HandoffCoordinator) cacheAndRespond(msg *nats.Msg, requestID string, resp *HandoffResponse) {
+	hc.processedMu.Lock()
+	hc.processed[requestID] = resp
+	hc.processedMu.Unlock()
+
+	respData, err := json.Marshal(resp)
+	if err != nil {
+		logger.ErrorCF("swarm", "Failed to encode handoff response", map[string]any{"error": err})
+		return
+	}
+	if err := msg.Respond(respData); err != nil {
+		logger.ErrorCF("swarm", "Failed to send handoff response", map[string]any{"error": err})
+	}
+}
+
+// CanHandle checks if the local node can handle a request.
+func (hc *HandoffCoordinator) CanHandle(requiredCap string) bool {
+	if !hc.config.Enabled {
+		return false
+	}
+
+	// Check load
+	localNode := hc.discovery.LocalNode()
+	loadScore := localNode.LoadScore
+	if loadScore > hc.config.LoadThreshold {
+		return false
+	}
+
+	// Check capability
+	if requiredCap != "" {
+		hasCap := false
+		for _, cap := range localNode.AgentCaps {
+			if cap == requiredCap {
+				hasCap = true
+				break
+			}
+		}
+		if !hasCap {
+			return false
+		}
+	}
+
+	return true
+}
+
+// InitiateHandoff initiates a handoff to another node via NATS request-reply.
+func (hc *HandoffCoordinator) InitiateHandoff(ctx context.Context, req *HandoffRequest) (*HandoffResponse, error) {
+	if hc.nc == nil {
+		return nil, ErrNATSNotConnected
+	}
+
+	if req.RequestID == "" {
+		req.RequestID = uuid.New().String()
+	}
+
+	localNode := hc.discovery.LocalNode()
+	req.FromNodeID = localNode.ID
+	req.FromNodeAddr = localNode.Addr
+	req.Timestamp = time.Now().UnixNano()
+
+	// Generate nonce for replay protection if auth is enabled
+	if hc.signer != nil && hc.cryptoConfig.RequireAuth && req.Nonce == "" {
+		req.Nonce = uuid.New().String()
+	}
+
+	// Find target node
+	targetNode, findErr := hc.findTargetNode(req)
+	if findErr != nil {
+		//nolint:nilerr // Failure is communicated via HandoffResponse, not Go error
+		return &HandoffResponse{
+			RequestID: req.RequestID,
+			Accepted:  false,
+			Reason:    findErr.Error(),
+			State:     HandoffStateFailed,
+		}, nil
+	}
+
+	// Create operation
+	op := &HandoffOperation{
+		Request:    req,
+		State:      HandoffStatePending,
+		StartTime:  time.Now(),
+		LastUpdate: time.Now(),
+		TargetNode: targetNode,
+	}
+
+	hc.mu.Lock()
+	hc.pending[req.RequestID] = op
+	hc.mu.Unlock()
+
+	// Send request via NATS request-reply to targeted subject
+	req.TargetNodeID = targetNode.Node.ID
+	resp, err := hc.sendHandoffRequest(ctx, targetNode.Node.ID, req)
+	if err != nil {
+		// System error - return immediately, don't retry
+		hc.mu.Lock()
+		delete(hc.pending, req.RequestID)
+		hc.mu.Unlock()
+		return nil, fmt.Errorf("handoff request failed: %w", err)
+	}
+
+	// Retry if needed
+retryLoop:
+	for !resp.Accepted && op.RetryCount < hc.config.MaxRetries {
+		op.RetryCount++
+		hc.metrics.RecordRetry()
+
+		// Find new target
+		newTarget, findErr := hc.findTargetNode(req)
+		if findErr != nil {
+			continue
+		}
+		op.TargetNode = newTarget
+
+		// Delay before retry
+		select {
+		case <-ctx.Done():
+			resp = &HandoffResponse{
+				RequestID: req.RequestID,
+				Accepted:  false,
+				Reason:    "context canceled",
+				State:     HandoffStateFailed,
+			}
+
+			break retryLoop
+		case <-time.After(hc.config.RetryDelay.Duration):
+		}
+
+		req.TargetNodeID = newTarget.Node.ID
+		var retryErr error
+		resp, retryErr = hc.sendHandoffRequest(ctx, newTarget.Node.ID, req)
+		if retryErr != nil {
+			// System error during retry - abort
+			hc.mu.Lock()
+			delete(hc.pending, req.RequestID)
+			hc.mu.Unlock()
+			return nil, fmt.Errorf("handoff retry failed: %w", retryErr)
+		}
+		if resp.Accepted {
+			break
+		}
+	}
+
+	// Clean up
+	hc.mu.Lock()
+	delete(hc.pending, req.RequestID)
+	hc.mu.Unlock()
+
+	// Notify callback
+	if hc.onHandoffComplete != nil {
+		go hc.onHandoffComplete(req, resp)
+	}
+
+	return resp, nil
+}
+
+// sendHandoffRequest sends a handoff request to a specific target node via NATS request-reply.
+// Returns error for system failures (NATS timeout, network error, serialization failure).
+// Returns HandoffResponse for business rejections (target node rejected).
+func (hc *HandoffCoordinator) sendHandoffRequest(
+	ctx context.Context,
+	targetNodeID string,
+	req *HandoffRequest,
+) (*HandoffResponse, error) {
+	startTime := time.Now()
+	hc.metrics.RecordRequest()
+
+	subject := SubjectHandoff + "." + targetNodeID
+
+	// Prepare the request for transmission
+	transmitReq := *req
+	var truncInfo *TruncationInfo
+
+	// Data minimization: limit session history to configured max
+	// This reduces payload size and avoids sending unnecessary historical data
+	if hc.config.MaxSessionHistory > 0 && len(transmitReq.SessionMessages) > hc.config.MaxSessionHistory {
+		originalCount := len(transmitReq.SessionMessages)
+
+		// Preserve system/developer messages, then take most recent conversation messages
+		var systemMessages []SessionMessage
+		var conversationMessages []SessionMessage
+
+		for _, msg := range transmitReq.SessionMessages {
+			if msg.Role == "system" || msg.Role == "developer" {
+				systemMessages = append(systemMessages, msg)
+			} else {
+				conversationMessages = append(conversationMessages, msg)
+			}
+		}
+
+		// Keep all system messages, but limit conversation to MaxSessionHistory
+		availableSlots := hc.config.MaxSessionHistory - len(systemMessages)
+		if availableSlots < 0 {
+			availableSlots = 0
+		}
+
+		if len(conversationMessages) > availableSlots {
+			// Take the most recent messages (from the end)
+			startIdx := len(conversationMessages) - availableSlots
+			conversationMessages = conversationMessages[startIdx:]
+		}
+
+		transmitReq.SessionMessages = append(systemMessages, conversationMessages...)
+
+		if len(transmitReq.SessionMessages) < originalCount {
+			logger.InfoCF("swarm", "Applied data minimization for handoff", map[string]any{
+				"original_count":    originalCount,
+				"transmitted_count": len(transmitReq.SessionMessages),
+				"max_history":       hc.config.MaxSessionHistory,
+			})
+		}
+	}
+
+	// Check message size against NATS max payload.
+	// If too large, truncate session history with smart rules.
+	data, err := json.Marshal(transmitReq)
+	if err != nil {
+		hc.metrics.RecordFailed()
+		return nil, fmt.Errorf("failed to marshal handoff request: %w", err)
+	}
+
+	originalSize := len(data)
+	originalCount := len(transmitReq.SessionMessages)
+
+	if len(data) > DefaultMaxHandoffPayloadBytes && len(transmitReq.SessionMessages) > 0 {
+		logger.WarnCF("swarm", "Handoff payload exceeds max size, truncating session history", map[string]any{
+			"original_size":    originalSize,
+			"max_size":         DefaultMaxHandoffPayloadBytes,
+			"original_history": originalCount,
+		})
+
+		transmitReq, data, truncInfo = hc.truncateSessionData(transmitReq, data)
+		hc.metrics.RecordTruncation()
+
+		if data == nil {
+			hc.metrics.RecordFailed()
+			return nil, fmt.Errorf("handoff payload too large even after truncation")
+		}
+
+		logger.InfoCF("swarm", "Session history truncated for handoff", map[string]any{
+			"original_count":  originalCount,
+			"remaining_count": len(transmitReq.SessionMessages),
+			"bytes_removed":   originalSize - len(data),
+		})
+	}
+
+	// Encrypt session data if configured
+	if hc.encryptor != nil && hc.cryptoConfig.RequireEncryption {
+		sessionData := map[string]any{
+			"session_messages": transmitReq.SessionMessages,
+			"context":          transmitReq.Context,
+		}
+		plainData, _ := json.Marshal(sessionData)
+		encrypted, encryptErr := hc.encryptor.Encrypt(plainData)
+		if encryptErr == nil {
+			transmitReq.EncryptedData = encrypted
+			transmitReq.SessionMessages = nil // Clear plaintext
+			transmitReq.Context = nil
+		}
+		data, err = json.Marshal(transmitReq)
+		if err != nil {
+			hc.metrics.RecordFailed()
+			return nil, fmt.Errorf("failed to marshal handoff request after encryption: %w", err)
+		}
+	}
+
+	// Sign the request
+	if hc.signer != nil {
+		signature, signErr := hc.signer.Sign(transmitReq.signingPayload())
+		if signErr != nil {
+			logger.WarnCF("swarm", "Failed to sign handoff request", map[string]any{"error": signErr})
+		} else {
+			transmitReq.Signature = signature
+			data, _ = json.Marshal(transmitReq)
+		}
+	}
+
+	// Use NATS request-reply (timeout controlled by parent context)
+	msg, err := hc.nc.RequestWithContext(ctx, subject, data)
+	if err != nil {
+		hc.metrics.RecordTimeout()
+		hc.circuitBreaker.RecordFailure(targetNodeID)
+		// Return system error for network/timeout failures
+		return nil, fmt.Errorf("NATS request failed: %w", err)
+	}
+
+	var resp HandoffResponse
+	if err := json.Unmarshal(msg.Data, &resp); err != nil {
+		hc.metrics.RecordFailed()
+		hc.circuitBreaker.RecordFailure(targetNodeID)
+		// Return system error for data corruption
+		return nil, fmt.Errorf("failed to decode handoff response: %w", err)
+	}
+
+	// Attach truncation info to response
+	resp.TruncationInfo = truncInfo
+
+	if resp.Accepted {
+		hc.metrics.RecordAccepted()
+		hc.circuitBreaker.RecordSuccess(targetNodeID)
+		hc.nodeCooldown.Remove(targetNodeID)
+	} else {
+		hc.metrics.RecordRejected()
+		hc.circuitBreaker.RecordFailure(targetNodeID)
+		// If rejected due to overload, add to cooldown
+		if resp.State == HandoffStateRejected && (resp.Reason == "cannot handle" || resp.Reason == "overloaded") {
+			hc.nodeCooldown.Add(targetNodeID)
+		}
+	}
+
+	hc.metrics.RecordLatency(time.Since(startTime))
+
+	return &resp, nil
+}
+
+// truncateSessionData smartly truncates session history, preserving important messages.
+func (hc *HandoffCoordinator) truncateSessionData(
+	req HandoffRequest,
+	data []byte,
+) (HandoffRequest, []byte, *TruncationInfo) {
+	truncated := req
+	originalCount := len(truncated.SessionMessages)
+	bytesRemoved := 0
+
+	// First pass: Remove oldest user/assistant messages, preserve system messages
+	var systemMessages []SessionMessage
+	var conversationMessages []SessionMessage
+
+	for _, msg := range truncated.SessionMessages {
+		if msg.Role == "system" || msg.Role == "developer" {
+			systemMessages = append(systemMessages, msg)
+		} else {
+			conversationMessages = append(conversationMessages, msg)
+		}
+	}
+
+	// Keep system messages, remove from oldest conversation messages first
+	for len(data) > DefaultMaxHandoffPayloadBytes && len(conversationMessages) > 0 {
+		removed := conversationMessages[0]
+		bytesRemoved += len(removed.Role) + len(removed.Content) + 20 // Approximate JSON overhead
+		conversationMessages = conversationMessages[1:]
+
+		truncated.SessionMessages = append(systemMessages, conversationMessages...)
+		var err error
+		data, err = json.Marshal(truncated)
+		if err != nil {
+			return req, nil, &TruncationInfo{
+				OriginalCount:  originalCount,
+				RemainingCount: len(truncated.SessionMessages),
+				BytesRemoved:   bytesRemoved,
+			}
+		}
+	}
+
+	// Second pass: If still too large, start removing from the end (keep recent)
+	systemMsgCount := len(systemMessages)
+	for len(data) > DefaultMaxHandoffPayloadBytes && len(truncated.SessionMessages) > systemMsgCount {
+		removed := truncated.SessionMessages[len(truncated.SessionMessages)-1]
+		bytesRemoved += len(removed.Role) + len(removed.Content) + 20
+		truncated.SessionMessages = truncated.SessionMessages[:len(truncated.SessionMessages)-1]
+
+		var err error
+		data, err = json.Marshal(truncated)
+		if err != nil {
+			return req, nil, &TruncationInfo{
+				OriginalCount:  originalCount,
+				RemainingCount: len(truncated.SessionMessages),
+				BytesRemoved:   bytesRemoved,
+			}
+		}
+	}
+
+	if len(data) > DefaultMaxHandoffPayloadBytes {
+		return req, nil, &TruncationInfo{
+			OriginalCount:  originalCount,
+			RemainingCount: len(truncated.SessionMessages),
+			BytesRemoved:   bytesRemoved,
+		}
+	}
+
+	return truncated, data, &TruncationInfo{
+		OriginalCount:  originalCount,
+		RemainingCount: len(truncated.SessionMessages),
+		BytesRemoved:   bytesRemoved,
+	}
+}
+
+// HandleIncomingHandoff handles a handoff request received from another node.
+func (hc *HandoffCoordinator) HandleIncomingHandoff(req *HandoffRequest) *HandoffResponse {
+	// Check if we can handle it
+	accepted := hc.CanHandle(req.RequiredCap)
+	localNode := hc.discovery.LocalNode()
+	response := &HandoffResponse{
+		RequestID: req.RequestID,
+		Accepted:  accepted,
+		NodeID:    localNode.ID,
+		State:     HandoffStateAccepted,
+		Timestamp: time.Now().UnixNano(),
+	}
+
+	if !accepted {
+		response.Reason = "cannot handle (overloaded or missing capability)"
+		response.State = HandoffStateRejected
+	}
+
+	// Call custom handler if set
+	if hc.onHandoffRequest != nil {
+		response = hc.onHandoffRequest(req)
+	}
+
+	return response
+}
+
+// findTargetNode finds a suitable target node for handoff.
+func (hc *HandoffCoordinator) findTargetNode(req *HandoffRequest) (*NodeWithState, error) {
+	var candidates []*NodeWithState
+
+	if req.RequiredCap != "" {
+		candidates = hc.membership.SelectByCapability([]string{req.RequiredCap})
+	} else {
+		candidates = hc.membership.GetAvailableMembers()
+	}
+
+	// Filter out nodes that are in circuit breaker open state or cooldown
+	var healthyCandidates []*NodeWithState
+	for _, c := range candidates {
+		nodeID := c.Node.ID
+		// Skip if circuit is open
+		if hc.circuitBreaker.GetState(nodeID) == CircuitOpen {
+			continue
+		}
+		// Skip if in overload cooldown
+		if hc.nodeCooldown.IsCooled(nodeID) {
+			continue
+		}
+		healthyCandidates = append(healthyCandidates, c)
+	}
+
+	if len(healthyCandidates) == 0 {
+		return nil, ErrNoHealthyNodes
+	}
+
+	// Select least loaded node
+	target := healthyCandidates[0]
+	for _, c := range healthyCandidates[1:] {
+		if c.Node.LoadScore < target.Node.LoadScore {
+			target = c
+		}
+	}
+
+	return target, nil
+}
+
+// SetRequestHandler sets a custom handler for handoff requests.
+func (hc *HandoffCoordinator) SetRequestHandler(handler func(*HandoffRequest) *HandoffResponse) {
+	hc.onHandoffRequest = handler
+}
+
+// SetCompleteHandler sets a callback for handoff completion.
+func (hc *HandoffCoordinator) SetCompleteHandler(handler func(*HandoffRequest, *HandoffResponse)) {
+	hc.onHandoffComplete = handler
+}
+
+// GetPending returns all pending handoff operations.
+func (hc *HandoffCoordinator) GetPending() []*HandoffOperation {
+	hc.mu.RLock()
+	defer hc.mu.RUnlock()
+
+	result := make([]*HandoffOperation, 0, len(hc.pending))
+	for _, op := range hc.pending {
+		result = append(result, op)
+	}
+	return result
+}
+
+// GetMetrics returns the current handoff metrics.
+func (hc *HandoffCoordinator) GetMetrics() *HandoffMetrics {
+	return hc.metrics
+}
+
+// ComponentHealth returns the health status of handoff components.
+func (hc *HandoffCoordinator) ComponentHealth() map[string]bool {
+	health := make(map[string]bool)
+	health["coordinator"] = hc.sub != nil
+	health["nats"] = hc.nc != nil
+	health["signing"] = hc.signer != nil && hc.signer.enabled
+	health["encryption"] = hc.encryptor != nil && hc.encryptor.enabled
+	health["discovery"] = hc.discovery != nil
+	health["membership"] = hc.membership != nil
+	return health
+}
+
+// GetCircuitBreakerStatus returns the circuit breaker state for all tracked nodes.
+func (hc *HandoffCoordinator) GetCircuitBreakerStatus() map[string]string {
+	status := make(map[string]string)
+	if hc.circuitBreaker == nil {
+		return status
+	}
+
+	// Get all members
+	if hc.membership != nil {
+		members := hc.membership.GetAvailableMembers()
+		for _, m := range members {
+			nodeID := m.Node.ID
+			state := hc.circuitBreaker.GetState(nodeID)
+			if state != "" {
+				status[nodeID] = string(state)
+			}
+		}
+	}
+	return status
+}

pkg/swarm/leader_election.go

@@ -0,0 +1,396 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/kv"
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// LeaderLockValue represents the value stored in the leader KV lock.
+type LeaderLockValue struct {
+	NodeID    string `json:"node_id"`
+	Timestamp int64  `json:"timestamp"` // Unix nano when lock was acquired/renewed
+	TTLMs     int64  `json:"ttl_ms"`    // TTL in milliseconds
+}
+
+// LeaderKey is the key used for leader election in the leader bucket.
+const LeaderKey = "leader"
+
+// LeaderElection handles leader election using Bucket with CAS (Compare-And-Swap).
+//
+// Flow:
+//   - On Start(), attempt to acquire the leader lock via bucket.Create (succeeds if key absent).
+//   - If key exists, check if TTL expired; if so, attempt CAS update to claim.
+//   - Leader renews the lock periodically (RenewalInterval < LockTTL).
+//   - Followers watch the key for changes; on delete/expire, they attempt acquisition.
+//   - On graceful shutdown, the leader deletes the key to trigger re-election.
+type LeaderElection struct {
+	localNodeID string
+	config      LeaderElectionConfig
+	bucket      kv.Bucket
+
+	mu             sync.RWMutex
+	currentLeader  string
+	isLeader       bool
+	lastRevision   uint64 // For CAS operations
+	leaderChangeCh chan string
+	stopCh         chan struct{}
+}
+
+// NewLeaderElection creates a new leader election instance using the leader bucket.
+func NewLeaderElection(nodeID string, bucket kv.Bucket, config LeaderElectionConfig) (*LeaderElection, error) {
+	if bucket == nil {
+		return nil, fmt.Errorf("bucket cannot be nil")
+	}
+
+	le := &LeaderElection{
+		localNodeID:    nodeID,
+		config:         config,
+		bucket:         bucket,
+		leaderChangeCh: make(chan string, 10),
+		stopCh:         make(chan struct{}),
+	}
+
+	return le, nil
+}
+
+// Start starts the leader election process.
+func (le *LeaderElection) Start() error {
+	// Attempt initial acquisition
+	le.tryAcquire()
+
+	// Start renewal or watch based on current role
+	go le.mainLoop()
+
+	return nil
+}
+
+// Stop stops the leader election process.
+func (le *LeaderElection) Stop() {
+	le.mu.Lock()
+	wasLeader := le.isLeader
+	le.mu.Unlock()
+
+	// If we are leader, delete the key to trigger re-election
+	if wasLeader && le.bucket != nil {
+		if err := le.bucket.Delete(LeaderKey); err != nil {
+			logger.WarnCF("swarm", "Failed to delete leader key on shutdown", map[string]any{"error": err})
+		}
+	}
+
+	close(le.stopCh)
+}
+
+// IsLeader returns true if this node is the current leader.
+func (le *LeaderElection) IsLeader() bool {
+	le.mu.RLock()
+	defer le.mu.RUnlock()
+	return le.isLeader
+}
+
+// GetLeader returns the current leader ID.
+func (le *LeaderElection) GetLeader() string {
+	le.mu.RLock()
+	defer le.mu.RUnlock()
+	return le.currentLeader
+}
+
+// LeaderChanges returns a channel that receives leader ID changes.
+func (le *LeaderElection) LeaderChanges() <-chan string {
+	return le.leaderChangeCh
+}
+
+// ElectLeader triggers a new leader election by deleting the current lock.
+func (le *LeaderElection) ElectLeader(ctx context.Context) (string, error) {
+	// Delete current lock to force re-election
+	if le.bucket != nil {
+		_ = le.bucket.Delete(LeaderKey)
+	}
+
+	// Wait for new leader
+	ticker := time.NewTicker(100 * time.Millisecond)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return "", ctx.Err()
+		case <-ticker.C:
+			le.mu.RLock()
+			leader := le.currentLeader
+			le.mu.RUnlock()
+			if leader != "" {
+				return leader, nil
+			}
+		}
+	}
+}
+
+// tryAcquire attempts to acquire the leader lock.
+func (le *LeaderElection) tryAcquire() {
+	lockTTL := le.config.LockTTL.Duration
+	if lockTTL <= 0 {
+		lockTTL = DefaultLeaderLockTTL
+	}
+
+	value := LeaderLockValue{
+		NodeID:    le.localNodeID,
+		Timestamp: time.Now().UnixNano(),
+		TTLMs:     lockTTL.Milliseconds(),
+	}
+	data, err := json.Marshal(value)
+	if err != nil {
+		logger.ErrorCF("swarm", "Failed to marshal leader lock value", map[string]any{"error": err})
+		return
+	}
+
+	// Try bucket.Create — succeeds only if key does not exist
+	rev, err := le.bucket.Create(LeaderKey, data)
+	if err == nil {
+		// Successfully acquired lock
+		le.mu.Lock()
+		le.lastRevision = rev
+		le.becomeLeader()
+		le.mu.Unlock()
+		return
+	}
+
+	// Key exists — check if current leader's lock is expired
+	entry, err := le.bucket.Get(LeaderKey)
+	if err != nil {
+		// Key might have been deleted between Create and Get
+		// Try create again
+		rev, err = le.bucket.Create(LeaderKey, data)
+		if err == nil {
+			le.mu.Lock()
+			le.lastRevision = rev
+			le.becomeLeader()
+			le.mu.Unlock()
+		}
+		return
+	}
+
+	var existing LeaderLockValue
+	if err = json.Unmarshal(entry.Value, &existing); err != nil {
+		return
+	}
+
+	// Check if existing lock is expired
+	lockAge := time.Since(time.Unix(0, existing.Timestamp))
+	existingTTL := time.Duration(existing.TTLMs) * time.Millisecond
+	if lockAge > existingTTL {
+		// Lock expired — attempt CAS update to claim it
+		rev, err = le.bucket.Update(LeaderKey, data, entry.Revision)
+		if err == nil {
+			le.mu.Lock()
+			le.lastRevision = rev
+			le.becomeLeader()
+			le.mu.Unlock()
+			return
+		}
+		// CAS failed — someone else claimed it
+	}
+
+	// We are a follower — update current leader info
+	le.mu.Lock()
+	le.setFollower(existing.NodeID)
+	le.mu.Unlock()
+}
+
+// mainLoop runs the renewal (if leader) or watch (if follower) loop.
+func (le *LeaderElection) mainLoop() {
+	for {
+		select {
+		case <-le.stopCh:
+			return
+		default:
+		}
+
+		le.mu.RLock()
+		amLeader := le.isLeader
+		le.mu.RUnlock()
+
+		if amLeader {
+			le.renewalLoop()
+		} else {
+			le.watchLoop()
+		}
+
+		// Backoff before re-entering loop after a role transition or error.
+		// Without this, a persistent issue would cause a tight spin.
+		select {
+		case <-le.stopCh:
+			return
+		case <-time.After(500 * time.Millisecond):
+		}
+	}
+}
+
+// renewalLoop periodically renews the leader lock.
+func (le *LeaderElection) renewalLoop() {
+	interval := le.config.RenewalInterval.Duration
+	if interval <= 0 {
+		interval = DefaultLeaderRenewalInterval
+	}
+
+	lockTTL := le.config.LockTTL.Duration
+	if lockTTL <= 0 {
+		lockTTL = DefaultLeaderLockTTL
+	}
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-le.stopCh:
+			return
+		case <-ticker.C:
+			value := LeaderLockValue{
+				NodeID:    le.localNodeID,
+				Timestamp: time.Now().UnixNano(),
+				TTLMs:     lockTTL.Milliseconds(),
+			}
+			data, err := json.Marshal(value)
+			if err != nil {
+				continue
+			}
+
+			le.mu.Lock()
+			rev, err := le.bucket.Update(LeaderKey, data, le.lastRevision)
+			if err != nil {
+				// CAS failed — lost leadership
+				logger.WarnCF("swarm", "Leader lock renewal failed, stepping down", map[string]any{
+					"node_id": le.localNodeID,
+					"error":   err,
+				})
+				le.isLeader = false
+				le.currentLeader = ""
+				le.mu.Unlock()
+				return // Exit renewal loop, mainLoop will start watchLoop
+			}
+			le.lastRevision = rev
+			le.mu.Unlock()
+		}
+	}
+}
+
+// watchLoop watches the leader key for changes and attempts acquisition on delete/expire.
+func (le *LeaderElection) watchLoop() {
+	watcher, err := le.bucket.Watch(LeaderKey)
+	if err != nil {
+		logger.ErrorCF("swarm", "Failed to watch leader key", map[string]any{"error": err})
+		// Retry after delay
+		select {
+		case <-le.stopCh:
+			return
+		case <-time.After(2 * time.Second):
+			return // mainLoop will retry
+		}
+	}
+	defer watcher.Stop()
+
+	for {
+		select {
+		case <-le.stopCh:
+			return
+		case entry := <-watcher.Updates():
+			if entry == nil {
+				continue
+			}
+
+			if entry.Operation == kv.EntryOperationDelete || entry.Operation == kv.EntryOperationPurge {
+				// Leader key deleted or expired — try to acquire
+				logger.InfoCF("swarm", "Leader key deleted/expired, attempting acquisition", nil)
+				le.tryAcquire()
+
+				le.mu.RLock()
+				amLeader := le.isLeader
+				le.mu.RUnlock()
+				if amLeader {
+					return // Exit watch loop, mainLoop will start renewalLoop
+				}
+				continue
+			}
+
+			// Leader key updated — check who the leader is
+			var lockVal LeaderLockValue
+			if err := json.Unmarshal(entry.Value, &lockVal); err != nil {
+				continue
+			}
+
+			le.mu.Lock()
+			if le.currentLeader != lockVal.NodeID {
+				le.setFollower(lockVal.NodeID)
+			}
+			le.mu.Unlock()
+		}
+	}
+}
+
+// becomeLeader marks this node as the leader. Must be called with mu held.
+func (le *LeaderElection) becomeLeader() {
+	if !le.isLeader {
+		le.isLeader = true
+		le.currentLeader = le.localNodeID
+		logger.InfoCF("swarm", "This node is now the leader", map[string]any{"node_id": le.localNodeID})
+
+		select {
+		case le.leaderChangeCh <- le.localNodeID:
+		default:
+			logger.WarnC("swarm", "Leader change notification dropped, channel full")
+		}
+	}
+}
+
+// setFollower marks this node as a follower with the given leader. Must be called with mu held.
+func (le *LeaderElection) setFollower(leaderID string) {
+	wasLeader := le.isLeader
+	le.isLeader = false
+	oldLeader := le.currentLeader
+	le.currentLeader = leaderID
+
+	if wasLeader || oldLeader != leaderID {
+		if wasLeader {
+			logger.InfoCF("swarm", "This node is now a follower", map[string]any{
+				"node_id":    le.localNodeID,
+				"new_leader": leaderID,
+			})
+		}
+
+		select {
+		case le.leaderChangeCh <- leaderID:
+		default:
+			logger.WarnC("swarm", "Leader change notification dropped, channel full")
+		}
+	}
+}
+
+// LeadershipState represents the current leadership state.
+type LeadershipState struct {
+	LeaderID   string `json:"leader_id"`
+	IsLeader   bool   `json:"is_leader"`
+	LastChange int64  `json:"last_change"` // Unix nano
+}
+
+// GetState returns the current leadership state.
+func (le *LeaderElection) GetState() LeadershipState {
+	le.mu.RLock()
+	defer le.mu.RUnlock()
+
+	return LeadershipState{
+		LeaderID: le.currentLeader,
+		IsLeader: le.isLeader,
+	}
+}

pkg/swarm/load_monitor.go

@@ -0,0 +1,331 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// LoadMonitor monitors system load and calculates a load score.
+type LoadMonitor struct {
+	config       *LoadMonitorConfig
+	samples      []float64
+	mu           sync.RWMutex
+	sessionCount int
+	ticker       *time.Ticker
+	stopChan     chan struct{}
+	stopOnce     sync.Once
+	started      bool
+	onThreshold  []func(float64)
+}
+
+// NewLoadMonitor creates a new load monitor.
+func NewLoadMonitor(config *LoadMonitorConfig) *LoadMonitor {
+	if config.SampleSize <= 0 {
+		config.SampleSize = 60
+	}
+	if config.Interval.Duration <= 0 {
+		config.Interval = Duration{5 * time.Second}
+	}
+
+	lm := &LoadMonitor{
+		config:      config,
+		samples:     make([]float64, 0, config.SampleSize),
+		stopChan:    make(chan struct{}),
+		onThreshold: make([]func(float64), 0),
+	}
+	return lm
+}
+
+// Start begins monitoring load.
+func (lm *LoadMonitor) Start() {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+
+	if lm.started {
+		return
+	}
+
+	lm.stopChan = make(chan struct{})
+	lm.stopOnce = sync.Once{}
+	lm.ticker = time.NewTicker(lm.config.Interval.Duration)
+	lm.started = true
+	go lm.run()
+}
+
+// Stop stops monitoring load. Safe to call multiple times.
+func (lm *LoadMonitor) Stop() {
+	lm.stopOnce.Do(func() {
+		lm.mu.Lock()
+		defer lm.mu.Unlock()
+
+		if !lm.started {
+			return
+		}
+
+		if lm.ticker != nil {
+			lm.ticker.Stop()
+			lm.ticker = nil
+		}
+		close(lm.stopChan)
+		lm.started = false
+
+		logger.DebugC("swarm", "Load monitor stopped")
+	})
+}
+
+// run is the main monitoring loop.
+func (lm *LoadMonitor) run() {
+	for {
+		select {
+		case <-lm.ticker.C:
+			score := lm.calculateScore()
+			lm.addSample(score)
+
+			// Check threshold callbacks
+			if lm.shouldOffload() {
+				lm.mu.RLock()
+				callbacks := make([]func(float64), len(lm.onThreshold))
+				copy(callbacks, lm.onThreshold)
+				lm.mu.RUnlock()
+
+				for _, cb := range callbacks {
+					go cb(score)
+				}
+			}
+		case <-lm.stopChan:
+			return
+		}
+	}
+}
+
+// LoadMetrics represents current load metrics.
+type LoadMetrics struct {
+	CPUUsage       float64 `json:"cpu_usage"`
+	MemoryUsage    float64 `json:"memory_usage"`
+	MemoryBytes    uint64  `json:"memory_bytes"`
+	ActiveSessions int     `json:"active_sessions"`
+	Goroutines     int     `json:"goroutines"`
+	Score          float64 `json:"score"`
+	Timestamp      int64   `json:"timestamp"`
+}
+
+// GetCurrentLoad returns the current load metrics.
+func (lm *LoadMonitor) GetCurrentLoad() *LoadMetrics {
+	// Get memory usage
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	metrics := &LoadMetrics{
+		ActiveSessions: lm.GetSessionCount(),
+		Goroutines:     runtime.NumGoroutine(),
+		MemoryBytes:    m.Alloc,
+		Timestamp:      time.Now().UnixNano(),
+	}
+
+	// Normalize using configured thresholds
+	maxMem := lm.config.MaxMemoryBytes
+	if maxMem == 0 {
+		maxMem = 1024 * 1024 * 1024 // Default 1GB
+	}
+	metrics.MemoryUsage = normalizeMemory(m.Alloc, maxMem)
+
+	maxGoroutines := lm.config.MaxGoroutines
+	if maxGoroutines == 0 {
+		maxGoroutines = 1000
+	}
+	// Note: CPUUsage is approximated from goroutine count, not actual CPU sampling.
+	// For production accuracy, consider using OS-level CPU metrics.
+	metrics.CPUUsage = normalizeGoroutines(metrics.Goroutines, maxGoroutines)
+
+	maxSessions := lm.config.MaxSessions
+	if maxSessions == 0 {
+		maxSessions = 100
+	}
+	sessionUsage := normalizeSessions(metrics.ActiveSessions, maxSessions)
+
+	// Calculate weighted score
+	config := lm.config
+	metrics.Score = (metrics.CPUUsage * config.CPUWeight) +
+		(metrics.MemoryUsage * config.MemoryWeight) +
+		(sessionUsage * config.SessionWeight)
+
+	// Clamp score to [0, 1]
+	if metrics.Score < 0 {
+		metrics.Score = 0
+	} else if metrics.Score > 1 {
+		metrics.Score = 1
+	}
+
+	return metrics
+}
+
+// calculateScore calculates the current load score.
+func (lm *LoadMonitor) calculateScore() float64 {
+	return lm.GetCurrentLoad().Score
+}
+
+// addSample adds a load sample to the history.
+func (lm *LoadMonitor) addSample(score float64) {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+
+	lm.samples = append(lm.samples, score)
+	if len(lm.samples) > lm.config.SampleSize {
+		lm.samples = lm.samples[1:]
+	}
+}
+
+// GetAverageScore returns the average load score over the sample window.
+func (lm *LoadMonitor) GetAverageScore() float64 {
+	lm.mu.RLock()
+	defer lm.mu.RUnlock()
+
+	if len(lm.samples) == 0 {
+		return lm.calculateScore()
+	}
+
+	sum := 0.0
+	for _, s := range lm.samples {
+		sum += s
+	}
+	return sum / float64(len(lm.samples))
+}
+
+// GetSessionCount returns the current number of active sessions.
+func (lm *LoadMonitor) GetSessionCount() int {
+	lm.mu.RLock()
+	defer lm.mu.RUnlock()
+	return lm.sessionCount
+}
+
+// SetSessionCount sets the current number of active sessions.
+func (lm *LoadMonitor) SetSessionCount(count int) {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+	lm.sessionCount = count
+}
+
+// IncrementSessions increments the session count.
+func (lm *LoadMonitor) IncrementSessions() {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+	lm.sessionCount++
+}
+
+// DecrementSessions decrements the session count.
+func (lm *LoadMonitor) DecrementSessions() {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+	if lm.sessionCount > 0 {
+		lm.sessionCount--
+	}
+}
+
+// ShouldOffload returns true if the load is high enough to offload tasks.
+func (lm *LoadMonitor) ShouldOffload() bool {
+	return lm.shouldOffload()
+}
+
+// shouldOffload internal check for offloading.
+func (lm *LoadMonitor) shouldOffload() bool {
+	avgScore := lm.GetAverageScore()
+	currentScore := lm.calculateScore()
+
+	// Use configured offload threshold, or default to 0.8
+	threshold := lm.config.OffloadThreshold
+	if threshold <= 0 {
+		threshold = 0.8
+	}
+
+	// Use a combination of current and average for smoother behavior
+	combinedScore := (currentScore*0.7 + avgScore*0.3)
+	return combinedScore > threshold
+}
+
+// OnThreshold registers a callback when the load threshold is exceeded.
+func (lm *LoadMonitor) OnThreshold(callback func(float64)) {
+	lm.mu.Lock()
+	defer lm.mu.Unlock()
+	lm.onThreshold = append(lm.onThreshold, callback)
+}
+
+// GetTrend returns the load trend.
+func (lm *LoadMonitor) GetTrend() LoadTrend {
+	lm.mu.RLock()
+	defer lm.mu.RUnlock()
+
+	if len(lm.samples) < 3 {
+		return LoadTrendStable
+	}
+
+	// Simple linear regression to detect trend
+	n := float64(len(lm.samples))
+	sumX := n * (n - 1) / 2
+	sumY := 0.0
+	sumXY := 0.0
+
+	for i, s := range lm.samples {
+		x := float64(i)
+		sumY += s
+		sumXY += x * s
+	}
+
+	slope := (n*sumXY - sumX*sumY) / (n * (n - 1) * (2*n - 1) / 6)
+
+	if slope > TrendIncreasingThreshold {
+		return LoadTrendIncreasing
+	} else if slope < TrendDecreasingThreshold {
+		return LoadTrendDecreasing
+	}
+	return LoadTrendStable
+}
+
+// Helper functions for normalization
+
+func normalizeMemory(alloc uint64, maxMem uint64) float64 {
+	// Use configured max memory threshold
+	usage := float64(alloc) / float64(maxMem)
+	if usage > 1 {
+		return 1
+	}
+	return usage
+}
+
+// normalizeGoroutines normalizes goroutine count to a 0-1 score.
+// This is used as a CPU usage proxy; goroutine count correlates loosely
+// with CPU load but does not measure actual CPU utilization.
+func normalizeGoroutines(goroutines int, maxGoroutines int) float64 {
+	usage := float64(goroutines) / float64(maxGoroutines)
+	if usage > 1 {
+		return 1
+	}
+	return usage
+}
+
+func normalizeSessions(sessions int, maxSessions int) float64 {
+	// Use configured max sessions threshold
+	usage := float64(sessions) / float64(maxSessions)
+	if usage > 1 {
+		return 1
+	}
+	return usage
+}
+
+// GetLoadScore returns the current load score for the LoadReporter interface.
+func (lm *LoadMonitor) GetLoadScore() float64 {
+	return lm.GetAverageScore()
+}
+
+// LoadScore returns the current load score (alias for GetLoadScore).
+func (lm *LoadMonitor) LoadScore() float64 {
+	return lm.GetLoadScore()
+}

pkg/swarm/load_reporter_interface.go

@@ -0,0 +1,16 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+// LoadReporter provides load information for routing decisions.
+type LoadReporter interface {
+	// GetLoadScore returns the current load score (0-1).
+	GetLoadScore() float64
+
+	// ShouldOffload returns true if the load is high enough to offload tasks.
+	ShouldOffload() bool
+}

pkg/swarm/manager.go

@@ -0,0 +1,335 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) icoClaw contributors
+
+package swarm
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// SwarmManager manages the swarm cluster by coordinating discovery,
+// leadership, routing, load monitoring, and handoff.
+//
+// This is the main entry point for swarm mode. It composes the various
+// swarm subsystems and provides a unified API.
+type SwarmManager struct {
+	config *Config
+
+	// Core components
+	discovery   NodeDiscovery
+	rawDS       *DiscoveryService // Keep reference to access BucketSet
+	coordinator Coordinator
+	router      Router
+	loadMonitor LoadReporter
+	handoff     *HandoffCoordinator
+
+	// Local node info
+	localNode *NodeInfo
+
+	// Current view (cached for fast access)
+	currentView View
+	viewMu      sync.RWMutex
+
+	// Lifecycle
+	running bool
+	mu      sync.RWMutex
+	stopCh  chan struct{}
+
+	// Callbacks
+	onViewChange []func(View)
+}
+
+// NewSwarmManager creates a new swarm manager.
+func NewSwarmManager(cfg *Config) (*SwarmManager, error) {
+	if !cfg.Enabled {
+		return nil, ErrDiscoveryDisabled
+	}
+
+	sm := &SwarmManager{
+		config:       cfg,
+		currentView:  View{LocalNodeID: cfg.NodeID},
+		stopCh:       make(chan struct{}),
+		onViewChange: make([]func(View), 0),
+	}
+
+	// Create NATS discovery service
+	rawDS, err := NewDiscoveryService(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create discovery service: %w", err)
+	}
+	sm.rawDS = rawDS
+
+	// Wrap in adapter to implement NodeDiscovery interface
+	ds := NewDiscoveryAdapter(rawDS)
+	sm.discovery = ds
+	sm.localNode = rawDS.LocalNode()
+	sm.currentView.LocalNodeID = sm.localNode.ID
+
+	// Create router
+	sm.router = NewDefaultRouter(cfg.Handoff)
+
+	// Create load monitor
+	lm := NewLoadMonitor(&cfg.LoadMonitor)
+	sm.loadMonitor = lm
+
+	// Create handoff coordinator
+	sm.handoff = NewHandoffCoordinator(rawDS, cfg.Handoff)
+	if err := sm.handoff.SetCryptoConfig(cfg.Handoff.Crypto); err != nil {
+		logger.WarnCF("swarm", "Handoff crypto configuration warning", map[string]any{"error": err})
+	}
+
+	return sm, nil
+}
+
+// Start starts the swarm manager and all its subsystems.
+func (sm *SwarmManager) Start() error {
+	sm.mu.Lock()
+	defer sm.mu.Unlock()
+
+	if sm.running {
+		return nil
+	}
+
+	// Start discovery (this also creates buckets)
+	if err := sm.discovery.Start(); err != nil {
+		return fmt.Errorf("failed to start discovery: %w", err)
+	}
+
+	// Create leader election coordinator (if enabled) - must be after discovery starts
+	if sm.config.LeaderElection.Enabled {
+		buckets := sm.rawDS.Buckets()
+		if buckets != nil {
+			coordinator, err := NewCoordinatorAdapter(buckets, sm.config.NodeID, sm.config.LeaderElection)
+			if err != nil {
+				sm.discovery.Stop()
+				return fmt.Errorf("failed to create coordinator: %w", err)
+			}
+			sm.coordinator = coordinator
+
+			// Start coordinator
+			if err := sm.coordinator.Start(); err != nil {
+				sm.discovery.Stop()
+				return fmt.Errorf("failed to start coordinator: %w", err)
+			}
+		}
+	}
+
+	// Start load monitor
+	if lm, ok := sm.loadMonitor.(*LoadMonitor); ok {
+		lm.Start()
+	}
+
+	// Start handoff coordinator
+	if sm.handoff != nil {
+		if err := sm.handoff.Start(); err != nil {
+			logger.WarnCF("swarm", "Failed to start handoff coordinator", map[string]any{"error": err})
+		}
+	}
+
+	// Watch for node changes
+	cancelWatch := sm.discovery.WatchNodes(sm.onViewUpdate)
+	go func() {
+		<-sm.stopCh
+		cancelWatch()
+	}()
+
+	sm.running = true
+	logger.InfoCF("swarm", "Swarm manager started", map[string]any{
+		"node_id": sm.localNode.ID,
+	})
+
+	return nil
+}
+
+// Stop stops the swarm manager and all its subsystems.
+func (sm *SwarmManager) Stop() error {
+	sm.mu.Lock()
+	defer sm.mu.Unlock()
+
+	if !sm.running {
+		return nil
+	}
+
+	close(sm.stopCh)
+
+	// Stop handoff
+	if sm.handoff != nil {
+		_ = sm.handoff.Close()
+	}
+
+	// Stop load monitor
+	if lm, ok := sm.loadMonitor.(*LoadMonitor); ok {
+		lm.Stop()
+	}
+
+	// Stop coordinator
+	if sm.coordinator != nil {
+		sm.coordinator.Stop()
+	}
+
+	// Stop discovery
+	_ = sm.discovery.Stop()
+
+	sm.running = false
+	logger.InfoCF("swarm", "Swarm manager stopped", nil)
+
+	return nil
+}
+
+// onViewUpdate is called when the cluster view changes.
+func (sm *SwarmManager) onViewUpdate(view View) {
+	sm.viewMu.Lock()
+	sm.currentView = view
+	sm.viewMu.Unlock()
+
+	// Notify callbacks
+	for _, cb := range sm.onViewChange {
+		go func(f func(View)) {
+			defer func() {
+				if r := recover(); r != nil {
+					logger.ErrorCF("swarm", "View change callback panic", map[string]any{"panic": r})
+				}
+			}()
+			f(view)
+		}(cb)
+	}
+
+	logger.DebugCF("swarm", "Cluster view updated", map[string]any{
+		"node_count":  len(view.Nodes),
+		"alive_count": len(view.AliveNodes()),
+	})
+}
+
+// GetView returns the current cluster view.
+func (sm *SwarmManager) GetView() View {
+	sm.viewMu.RLock()
+	defer sm.viewMu.RUnlock()
+	return sm.currentView
+}
+
+// AliveNodes returns the current list of alive nodes.
+func (sm *SwarmManager) AliveNodes() []*NodeInfo {
+	return sm.discovery.AliveNodes()
+}
+
+// LocalNode returns the local node info.
+func (sm *SwarmManager) LocalNode() *NodeInfo {
+	return sm.localNode
+}
+
+// IsLeader returns true if this node is the leader.
+func (sm *SwarmManager) IsLeader() bool {
+	if sm.coordinator == nil {
+		return false
+	}
+	return sm.coordinator.IsLeader()
+}
+
+// LeaderID returns the current leader ID.
+func (sm *SwarmManager) LeaderID() string {
+	if sm.coordinator == nil {
+		return ""
+	}
+	return sm.coordinator.LeaderID()
+}
+
+// PickNode selects a node for the given task.
+func (sm *SwarmManager) PickNode(task Task) RoutingDecision {
+	view := sm.GetView()
+	return sm.router.PickNode(task, view)
+}
+
+// CanHandleLocally checks if the local node can handle the given task.
+func (sm *SwarmManager) CanHandleLocally(task Task) bool {
+	return sm.router.CanHandleLocally(task, sm.loadMonitor.GetLoadScore())
+}
+
+// GetLoad returns the current load score.
+func (sm *SwarmManager) GetLoad() float64 {
+	return sm.loadMonitor.GetLoadScore()
+}
+
+// ShouldOffload returns true if the load is high enough to offload tasks.
+func (sm *SwarmManager) ShouldOffload() bool {
+	return sm.loadMonitor.ShouldOffload()
+}
+
+// UpdateLoad updates the local node's load score.
+func (sm *SwarmManager) UpdateLoad(score float64) {
+	if updater, ok := sm.discovery.(NodeInfoUpdater); ok {
+		updater.UpdateLoad(score)
+	}
+}
+
+// UpdateCapabilities updates the local node's agent capabilities.
+func (sm *SwarmManager) UpdateCapabilities(caps map[string]string) {
+	if updater, ok := sm.discovery.(NodeInfoUpdater); ok {
+		updater.UpdateCapabilities(caps)
+	}
+}
+
+// Handoff initiates a handoff to another node.
+func (sm *SwarmManager) Handoff(ctx context.Context, req *HandoffRequest) (*HandoffResponse, error) {
+	if sm.handoff == nil {
+		return nil, fmt.Errorf("handoff not enabled")
+	}
+	return sm.handoff.InitiateHandoff(ctx, req)
+}
+
+// OnViewChange registers a callback for cluster view changes.
+func (sm *SwarmManager) OnViewChange(callback func(View)) {
+	sm.mu.Lock()
+	defer sm.mu.Unlock()
+	sm.onViewChange = append(sm.onViewChange, callback)
+}
+
+// OnLeaderChange registers a callback for leader changes.
+func (sm *SwarmManager) OnLeaderChange(callback func(leaderID string)) {
+	if sm.coordinator == nil {
+		return
+	}
+
+	ch := sm.coordinator.LeaderChanges()
+	go func() {
+		for leaderID := range ch {
+			callback(leaderID)
+		}
+	}()
+}
+
+// OnLoadThreshold registers a callback when load threshold is exceeded.
+func (sm *SwarmManager) OnLoadThreshold(callback func(float64)) {
+	if lm, ok := sm.loadMonitor.(*LoadMonitor); ok {
+		lm.OnThreshold(callback)
+	}
+}
+
+// GetDiscovery returns the underlying discovery service (for compatibility).
+func (sm *SwarmManager) GetDiscovery() NodeDiscovery {
+	return sm.discovery
+}
+
+// GetHandoffCoordinator returns the handoff coordinator.
+func (sm *SwarmManager) GetHandoffCoordinator() *HandoffCoordinator {
+	return sm.handoff
+}
+
+// GetLoadMonitor returns the load monitor.
+func (sm *SwarmManager) GetLoadMonitor() *LoadMonitor {
+	if lm, ok := sm.loadMonitor.(*LoadMonitor); ok {
+		return lm
+	}
+	return nil
+}
+
+// GetBuckets returns the bucket set.
+func (sm *SwarmManager) GetBuckets() *BucketSet {
+	return sm.rawDS.Buckets()
+}

pkg/swarm/membership.go

@@ -0,0 +1,385 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+// MembershipManager manages cluster membership.
+type MembershipManager struct {
+	discovery Discovery
+	view      *ClusterView
+	config    DiscoveryConfig
+	mu        sync.RWMutex
+
+	// Tracks nodes with pending dead-node removal goroutines
+	pendingRemoval map[string]struct{}
+
+	// Event callbacks
+	onJoin   []func(*NodeInfo)
+	onLeave  []func(*NodeInfo)
+	onUpdate []func(*NodeInfo)
+}
+
+// NewMembershipManager creates a new membership manager.
+func NewMembershipManager(ds Discovery, config DiscoveryConfig) *MembershipManager {
+	localNodeID := ds.LocalNode().ID
+	return &MembershipManager{
+		discovery:      ds,
+		view:           NewClusterView(localNodeID),
+		config:         config,
+		pendingRemoval: make(map[string]struct{}),
+		onJoin:         make([]func(*NodeInfo), 0),
+		onLeave:        make([]func(*NodeInfo), 0),
+		onUpdate:       make([]func(*NodeInfo), 0),
+	}
+}
+
+// GetNode retrieves a node by ID.
+func (mm *MembershipManager) GetNode(nodeID string) (*NodeWithState, bool) {
+	return mm.view.Get(nodeID)
+}
+
+// GetMembers returns all members.
+func (mm *MembershipManager) GetMembers() []*NodeWithState {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+	return mm.view.List()
+}
+
+// GetAliveMembers returns all alive members.
+func (mm *MembershipManager) GetAliveMembers() []*NodeWithState {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+
+	members := mm.view.GetAliveNodes()
+	result := make([]*NodeWithState, 0, len(members))
+	for _, m := range members {
+		if m.Node.ID != mm.discovery.LocalNode().ID {
+			result = append(result, m)
+		}
+	}
+	return result
+}
+
+// GetAvailableMembers returns all available members (alive and not overloaded).
+func (mm *MembershipManager) GetAvailableMembers() []*NodeWithState {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+
+	members := mm.view.GetAvailableNodes()
+	result := make([]*NodeWithState, 0, len(members))
+	for _, m := range members {
+		if m.Node.ID != mm.discovery.LocalNode().ID {
+			result = append(result, m)
+		}
+	}
+	return result
+}
+
+// UpdateNode updates or adds a node to the membership.
+func (mm *MembershipManager) UpdateNode(node *NodeInfo) *NodeWithState {
+	mm.mu.Lock()
+
+	existing, existed := mm.view.Get(node.ID)
+	nws := mm.view.AddOrUpdate(node)
+
+	// Determine what event to fire and collect callbacks while under lock
+	var eventType EventType
+	var callbacks []func(*NodeInfo)
+
+	if !existed {
+		// New node joined
+		nws.State.Status = NodeStatusAlive
+		nws.State.StatusSince = time.Now().UnixNano()
+		nws.State.LastSeen = time.Now().UnixNano()
+
+		eventType = EventJoin
+		callbacks = make([]func(*NodeInfo), len(mm.onJoin))
+		copy(callbacks, mm.onJoin)
+	} else if existing.Node.Timestamp < node.Timestamp {
+		// Existing node updated
+		nws.State.LastSeen = time.Now().UnixNano()
+
+		// Mark as alive if was suspect/dead
+		if nws.State.Status != NodeStatusAlive {
+			nws.State.UpdateStatus(NodeStatusAlive)
+			nws.State.PingFailure = 0
+			nws.State.PingSuccess++
+		}
+
+		eventType = EventUpdate
+		callbacks = make([]func(*NodeInfo), len(mm.onUpdate))
+		copy(callbacks, mm.onUpdate)
+	}
+
+	// Copy node info for safe use outside lock
+	nodeCopy := *node
+	mm.mu.Unlock()
+
+	// Fire callbacks and dispatch event outside the lock
+	if eventType != "" {
+		for _, cb := range callbacks {
+			go cb(&nodeCopy)
+		}
+		mm.discovery.DispatchEvent(&NodeEvent{
+			Node:  &nodeCopy,
+			Event: eventType,
+			Time:  time.Now().UnixNano(),
+		})
+	}
+
+	return nws
+}
+
+// RemoveNode removes a node from the membership.
+func (mm *MembershipManager) RemoveNode(nodeID string) {
+	mm.mu.Lock()
+
+	nws, exists := mm.view.Get(nodeID)
+	if !exists {
+		mm.mu.Unlock()
+		return
+	}
+
+	// Copy node info before releasing lock
+	nodeCopy := *nws.Node
+	callbacks := make([]func(*NodeInfo), len(mm.onLeave))
+	copy(callbacks, mm.onLeave)
+
+	mm.view.Remove(nodeID)
+	mm.mu.Unlock()
+
+	// Notify callbacks and dispatch event outside the lock
+	for _, cb := range callbacks {
+		go cb(&nodeCopy)
+	}
+
+	mm.discovery.DispatchEvent(&NodeEvent{
+		Node:  &nodeCopy,
+		Event: EventLeave,
+		Time:  time.Now().UnixNano(),
+	})
+}
+
+// RecordHeartbeat records a heartbeat for a node.
+func (mm *MembershipManager) RecordHeartbeat(nodeID string) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+
+	nws, exists := mm.view.Get(nodeID)
+	if !exists {
+		return
+	}
+
+	nws.State.LastPing = time.Now().UnixNano()
+	nws.State.LastSeen = time.Now().UnixNano()
+
+	// Reset failure count and increment success
+	nws.State.PingFailure = 0
+	nws.State.PingSuccess++
+
+	// Mark as alive if was suspect
+	if nws.State.Status != NodeStatusAlive {
+		nws.State.UpdateStatus(NodeStatusAlive)
+	}
+}
+
+// MarkSuspect marks a node as suspect (possibly dead).
+func (mm *MembershipManager) MarkSuspect(nodeID string) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+
+	nws, exists := mm.view.Get(nodeID)
+	if !exists {
+		return
+	}
+
+	if nws.State.Status == NodeStatusAlive {
+		nws.State.UpdateStatus(NodeStatusSuspect)
+		nws.State.PingFailure++
+	}
+}
+
+// MarkDead marks a node as dead.
+func (mm *MembershipManager) MarkDead(nodeID string) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+
+	nws, exists := mm.view.Get(nodeID)
+	if !exists {
+		return
+	}
+
+	if nws.State.Status != NodeStatusDead {
+		nws.State.UpdateStatus(NodeStatusDead)
+
+		// Only spawn a removal goroutine if one isn't already pending
+		if _, pending := mm.pendingRemoval[nodeID]; !pending {
+			mm.pendingRemoval[nodeID] = struct{}{}
+			go func() {
+				time.Sleep(mm.config.DeadNodeTimeout.Duration)
+				mm.mu.Lock()
+				delete(mm.pendingRemoval, nodeID)
+				mm.mu.Unlock()
+				mm.RemoveNode(nodeID)
+			}()
+		}
+	}
+}
+
+// CheckHealth checks the health of all members and marks dead nodes.
+func (mm *MembershipManager) CheckHealth() {
+	mm.mu.RLock()
+	members := mm.view.List()
+	nodeTimeout := mm.config.NodeTimeout.Duration
+	deadTimeout := mm.config.DeadNodeTimeout.Duration
+	localNodeID := mm.discovery.LocalNode().ID
+	mm.mu.RUnlock()
+
+	now := time.Now()
+
+	for _, m := range members {
+		// Skip local node
+		if m.Node.ID == localNodeID {
+			continue
+		}
+
+		lastSeen := time.Unix(0, m.State.LastSeen)
+		age := now.Sub(lastSeen)
+
+		switch m.State.Status {
+		case NodeStatusAlive:
+			if age > nodeTimeout {
+				mm.MarkSuspect(m.Node.ID)
+			}
+		case NodeStatusSuspect:
+			if age > deadTimeout {
+				mm.MarkDead(m.Node.ID)
+			}
+		}
+	}
+}
+
+// SelectByCapability selects members that have the required capabilities.
+func (mm *MembershipManager) SelectByCapability(requiredCaps []string) []*NodeWithState {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+
+	localNodeID := mm.discovery.LocalNode().ID
+	members := mm.view.GetAvailableNodes()
+	result := make([]*NodeWithState, 0)
+
+	for _, m := range members {
+		if m.Node.ID == localNodeID {
+			continue
+		}
+
+		// If no capabilities required, include all available nodes
+		if len(requiredCaps) == 0 {
+			result = append(result, m)
+			continue
+		}
+
+		// Check if node has all required capabilities
+		hasAll := true
+		for _, cap := range requiredCaps {
+			found := false
+			for _, nodeCap := range m.Node.AgentCaps {
+				if nodeCap == cap {
+					found = true
+					break
+				}
+			}
+			if !found {
+				hasAll = false
+				break
+			}
+		}
+
+		if hasAll {
+			result = append(result, m)
+		}
+	}
+
+	return result
+}
+
+// SelectLeastLoaded selects the member with the lowest load score.
+func (mm *MembershipManager) SelectLeastLoaded() *NodeWithState {
+	members := mm.GetAvailableMembers()
+	if len(members) == 0 {
+		return nil
+	}
+
+	least := members[0]
+	for _, m := range members[1:] {
+		if m.Node.LoadScore < least.Node.LoadScore {
+			least = m
+		}
+	}
+
+	return least
+}
+
+// SelectRandom selects a random available member.
+func (mm *MembershipManager) SelectRandom() *NodeWithState {
+	members := mm.GetAvailableMembers()
+	if len(members) == 0 {
+		return nil
+	}
+
+	// Use crypto/rand for better random distribution
+	idx := rand.Intn(len(members))
+	return members[idx]
+}
+
+// GetClusterSize returns the current cluster size.
+func (mm *MembershipManager) GetClusterSize() int {
+	mm.mu.RLock()
+	defer mm.mu.RUnlock()
+	return mm.view.Size
+}
+
+// OnJoin registers a callback for node join events.
+func (mm *MembershipManager) OnJoin(callback func(*NodeInfo)) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+	mm.onJoin = append(mm.onJoin, callback)
+}
+
+// OnLeave registers a callback for node leave events.
+func (mm *MembershipManager) OnLeave(callback func(*NodeInfo)) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+	mm.onLeave = append(mm.onLeave, callback)
+}
+
+// OnUpdate registers a callback for node update events.
+func (mm *MembershipManager) OnUpdate(callback func(*NodeInfo)) {
+	mm.mu.Lock()
+	defer mm.mu.Unlock()
+	mm.onUpdate = append(mm.onUpdate, callback)
+}
+
+// StartHealthCheck starts the health check routine.
+// Note: When using NATS discovery, health checks are driven by KV TTL
+// and the stale-node checker in DiscoveryService. This method is kept
+// for API compatibility but can be called optionally for additional checks.
+func (mm *MembershipManager) StartHealthCheck(interval time.Duration) {
+	go func() {
+		ticker := time.NewTicker(interval)
+		defer ticker.Stop()
+
+		for range ticker.C {
+			mm.CheckHealth()
+		}
+	}()
+}

pkg/swarm/metrics.go

@@ -0,0 +1,624 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// HandoffMetrics tracks detailed handoff operation statistics.
+// Separate from the general MetricsCollector for finer-grained tracking.
+type HandoffMetrics struct {
+	// Counters
+	requests    atomic.Int64
+	accepted    atomic.Int64
+	rejected    atomic.Int64
+	failed      atomic.Int64
+	timeouts    atomic.Int64
+	retries     atomic.Int64
+	truncations atomic.Int64
+
+	// Result-labeled counters (for detailed observability)
+	resultsByReason map[string]*atomic.Int64 // result_reason -> counter
+
+	// Payload size tracking (bytes)
+	totalPayloadBytes atomic.Int64
+	maxPayloadBytes   atomic.Int64
+
+	// Latency tracking (in nanoseconds)
+	totalLatency atomic.Int64
+	latencyCount atomic.Int64
+
+	// Security events
+	authFailures  atomic.Int64
+	decryptErrors atomic.Int64
+	duplicates    atomic.Int64 // Replay attacks detected
+	expired       atomic.Int64 // Timestamp window violations
+
+	mu        sync.RWMutex
+	lastReset time.Time
+}
+
+// NewHandoffMetrics creates a new handoff-specific metrics collector.
+func NewHandoffMetrics() *HandoffMetrics {
+	return &HandoffMetrics{
+		resultsByReason: make(map[string]*atomic.Int64),
+		lastReset:       time.Now(),
+	}
+}
+
+// RecordRequest records a handoff request.
+func (m *HandoffMetrics) RecordRequest() {
+	m.requests.Add(1)
+}
+
+// RecordAccepted records an accepted handoff.
+func (m *HandoffMetrics) RecordAccepted() {
+	m.accepted.Add(1)
+}
+
+// RecordRejected records a rejected handoff.
+func (m *HandoffMetrics) RecordRejected() {
+	m.rejected.Add(1)
+}
+
+// RecordFailed records a failed handoff.
+func (m *HandoffMetrics) RecordFailed() {
+	m.failed.Add(1)
+}
+
+// RecordTimeout records a timeout.
+func (m *HandoffMetrics) RecordTimeout() {
+	m.timeouts.Add(1)
+}
+
+// RecordRetry records a retry attempt.
+func (m *HandoffMetrics) RecordRetry() {
+	m.retries.Add(1)
+}
+
+// RecordTruncation records a message truncation event.
+func (m *HandoffMetrics) RecordTruncation() {
+	m.truncations.Add(1)
+}
+
+// RecordLatency records a handoff operation latency.
+func (m *HandoffMetrics) RecordLatency(d time.Duration) {
+	m.totalLatency.Add(d.Nanoseconds())
+	m.latencyCount.Add(1)
+}
+
+// RecordAuthFailure records an authentication failure.
+func (m *HandoffMetrics) RecordAuthFailure() {
+	m.authFailures.Add(1)
+}
+
+// RecordDecryptError records a decryption error.
+func (m *HandoffMetrics) RecordDecryptError() {
+	m.decryptErrors.Add(1)
+}
+
+// RecordDuplicate records a replay attack detection.
+func (m *HandoffMetrics) RecordDuplicate() {
+	m.duplicates.Add(1)
+	m.recordResult("duplicate")
+}
+
+// RecordExpired records a timestamp window violation.
+func (m *HandoffMetrics) RecordExpired() {
+	m.expired.Add(1)
+	m.recordResult("expired")
+}
+
+// RecordResult records a result with a specific reason label.
+func (m *HandoffMetrics) RecordResult(reason string) {
+	m.recordResult(reason)
+}
+
+// recordResult is an internal method for recording labeled results.
+func (m *HandoffMetrics) recordResult(reason string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, exists := m.resultsByReason[reason]; !exists {
+		m.resultsByReason[reason] = &atomic.Int64{}
+	}
+	m.resultsByReason[reason].Add(1)
+}
+
+// RecordPayloadSize records the size of a handoff payload.
+func (m *HandoffMetrics) RecordPayloadSize(bytes int) {
+	m.totalPayloadBytes.Add(int64(bytes))
+
+	// Track max
+	for {
+		curMax := m.maxPayloadBytes.Load()
+		if int64(bytes) <= curMax {
+			return
+		}
+		if m.maxPayloadBytes.CompareAndSwap(curMax, int64(bytes)) {
+			return
+		}
+	}
+}
+
+// Snapshot returns a snapshot of current handoff metrics.
+func (m *HandoffMetrics) Snapshot() map[string]any {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	result := map[string]any{
+		"requests":            m.requests.Load(),
+		"accepted":            m.accepted.Load(),
+		"rejected":            m.rejected.Load(),
+		"failed":              m.failed.Load(),
+		"timeouts":            m.timeouts.Load(),
+		"retries":             m.retries.Load(),
+		"truncations":         m.truncations.Load(),
+		"auth_failures":       m.authFailures.Load(),
+		"decrypt_errors":      m.decryptErrors.Load(),
+		"duplicates":          m.duplicates.Load(),
+		"expired":             m.expired.Load(),
+		"avg_latency_ms":      m.avgLatencyMs(),
+		"payload_total_bytes": m.totalPayloadBytes.Load(),
+		"payload_max_bytes":   m.maxPayloadBytes.Load(),
+		"uptime_seconds":      time.Since(m.lastReset).Seconds(),
+	}
+
+	// Add result breakdown by reason
+	resultBreakdown := make(map[string]int64)
+	for reason, counter := range m.resultsByReason {
+		resultBreakdown[reason] = counter.Load()
+	}
+	if len(resultBreakdown) > 0 {
+		result["by_reason"] = resultBreakdown
+	}
+
+	return result
+}
+
+// avgLatencyMs returns the average latency in milliseconds.
+func (m *HandoffMetrics) avgLatencyMs() float64 {
+	count := m.latencyCount.Load()
+	if count == 0 {
+		return 0
+	}
+	total := m.totalLatency.Load()
+	return float64(total) / float64(count) / 1e6
+}
+
+// Reset clears all handoff metrics.
+func (m *HandoffMetrics) Reset() {
+	m.requests.Store(0)
+	m.accepted.Store(0)
+	m.rejected.Store(0)
+	m.failed.Store(0)
+	m.timeouts.Store(0)
+	m.retries.Store(0)
+	m.truncations.Store(0)
+	m.authFailures.Store(0)
+	m.decryptErrors.Store(0)
+	m.duplicates.Store(0)
+	m.expired.Store(0)
+	m.totalLatency.Store(0)
+	m.latencyCount.Store(0)
+	m.totalPayloadBytes.Store(0)
+	m.maxPayloadBytes.Store(0)
+
+	m.mu.Lock()
+	m.resultsByReason = make(map[string]*atomic.Int64)
+	m.mu.Unlock()
+
+	m.lastReset = time.Now()
+}
+
+// RoutingMetrics tracks node-to-node routing statistics.
+type RoutingMetrics struct {
+	// Counters
+	requestsTotal  atomic.Int64
+	requestsLocal  atomic.Int64
+	requestsRemote atomic.Int64
+
+	// Result-labeled counters
+	resultsByResult map[string]*atomic.Int64 // ok, timeout, unauthorized, no_target, etc.
+
+	// Latency tracking (in nanoseconds)
+	totalLatency atomic.Int64
+	latencyCount atomic.Int64
+
+	// Fallback tracking
+	fallbackCount atomic.Int64
+
+	mu        sync.RWMutex
+	lastReset time.Time
+}
+
+// NewRoutingMetrics creates a new routing metrics collector.
+func NewRoutingMetrics() *RoutingMetrics {
+	return &RoutingMetrics{
+		resultsByResult: make(map[string]*atomic.Int64),
+		lastReset:       time.Now(),
+	}
+}
+
+// RecordRequest records a routing request.
+func (m *RoutingMetrics) RecordRequest(isLocal bool) {
+	m.requestsTotal.Add(1)
+	if isLocal {
+		m.requestsLocal.Add(1)
+	} else {
+		m.requestsRemote.Add(1)
+	}
+}
+
+// RecordResult records a routing result with a label.
+func (m *RoutingMetrics) RecordResult(result string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, exists := m.resultsByResult[result]; !exists {
+		m.resultsByResult[result] = &atomic.Int64{}
+	}
+	m.resultsByResult[result].Add(1)
+}
+
+// RecordFallback records a fallback to local processing.
+func (m *RoutingMetrics) RecordFallback() {
+	m.fallbackCount.Add(1)
+}
+
+// RecordLatency records a routing operation latency.
+func (m *RoutingMetrics) RecordLatency(d time.Duration) {
+	m.totalLatency.Add(d.Nanoseconds())
+	m.latencyCount.Add(1)
+}
+
+// Snapshot returns a snapshot of current routing metrics.
+func (m *RoutingMetrics) Snapshot() map[string]any {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	result := map[string]any{
+		"requests_total":  m.requestsTotal.Load(),
+		"requests_local":  m.requestsLocal.Load(),
+		"requests_remote": m.requestsRemote.Load(),
+		"fallback_count":  m.fallbackCount.Load(),
+		"avg_latency_ms":  m.avgLatencyMs(),
+		"uptime_seconds":  time.Since(m.lastReset).Seconds(),
+	}
+
+	// Add result breakdown
+	resultBreakdown := make(map[string]int64)
+	for label, counter := range m.resultsByResult {
+		resultBreakdown[label] = counter.Load()
+	}
+	if len(resultBreakdown) > 0 {
+		result["by_result"] = resultBreakdown
+	}
+
+	return result
+}
+
+func (m *RoutingMetrics) avgLatencyMs() float64 {
+	count := m.latencyCount.Load()
+	if count == 0 {
+		return 0
+	}
+	total := m.totalLatency.Load()
+	return float64(total) / float64(count) / 1e6
+}
+
+// MetricsCollector collects and exports metrics for the swarm cluster.
+type MetricsCollector struct {
+	mu sync.RWMutex
+
+	// Counters (atomic for performance)
+	messagesSent      atomic.Int64
+	messagesReceived  atomic.Int64
+	handoffsInitiated atomic.Int64
+	handoffsAccepted  atomic.Int64
+	handoffsRejected  atomic.Int64
+	handoffsFailed    atomic.Int64
+	electionsWon      atomic.Int64
+
+	// NATS-specific counters
+	natsPublished  atomic.Int64
+	natsReceived   atomic.Int64
+	leaderAcquired atomic.Int64
+	leaderLost     atomic.Int64
+
+	// Gauges (use atomic.Value for float64)
+	currentLoadScore atomic.Value // float64
+	activeSessions   atomic.Int64
+	memberCount      atomic.Int32
+
+	// Histogram data (simplified)
+	latencyBuckets map[string]*LatencyBucket
+
+	startTime time.Time
+}
+
+// LatencyBucket tracks latency distribution.
+type LatencyBucket struct {
+	mu      sync.RWMutex
+	count   int64
+	sum     int64
+	buckets [12]int64 // 0-1ms, 1-2ms, 2-5ms, 5-10ms, 10-20ms, 20-50ms, 50-100ms, 100-200ms, 200-500ms, 500ms-1s, 1-2s, 2s+
+}
+
+// NewMetricsCollector creates a new metrics collector.
+func NewMetricsCollector() *MetricsCollector {
+	mc := &MetricsCollector{
+		latencyBuckets: make(map[string]*LatencyBucket),
+		startTime:      time.Now(),
+	}
+	return mc
+}
+
+// Counter methods
+
+// MessagesSent increments the sent message counter.
+func (m *MetricsCollector) MessagesSent(n int64) {
+	m.messagesSent.Add(n)
+}
+
+// MessagesReceived increments the received message counter.
+func (m *MetricsCollector) MessagesReceived(n int64) {
+	m.messagesReceived.Add(n)
+}
+
+// HandoffInitiated increments the handoff initiated counter.
+func (m *MetricsCollector) HandoffInitiated() {
+	m.handoffsInitiated.Add(1)
+}
+
+// HandoffAccepted increments the handoff accepted counter.
+func (m *MetricsCollector) HandoffAccepted() {
+	m.handoffsAccepted.Add(1)
+}
+
+// HandoffRejected increments the handoff rejected counter.
+func (m *MetricsCollector) HandoffRejected() {
+	m.handoffsRejected.Add(1)
+}
+
+// HandoffFailed increments the handoff failed counter.
+func (m *MetricsCollector) HandoffFailed() {
+	m.handoffsFailed.Add(1)
+}
+
+// ElectionWon increments the elections won counter.
+func (m *MetricsCollector) ElectionWon() {
+	m.electionsWon.Add(1)
+}
+
+// NATSPublished increments the NATS published message counter.
+func (m *MetricsCollector) NATSPublished(n int64) {
+	m.natsPublished.Add(n)
+}
+
+// NATSReceived increments the NATS received message counter.
+func (m *MetricsCollector) NATSReceived(n int64) {
+	m.natsReceived.Add(n)
+}
+
+// LeaderAcquired increments the leader lock acquired counter.
+func (m *MetricsCollector) LeaderAcquired() {
+	m.leaderAcquired.Add(1)
+}
+
+// LeaderLost increments the leader lock lost counter.
+func (m *MetricsCollector) LeaderLost() {
+	m.leaderLost.Add(1)
+}
+
+// Gauge methods
+
+// SetLoadScore sets the current load score.
+func (m *MetricsCollector) SetLoadScore(score float64) {
+	m.currentLoadScore.Store(score)
+}
+
+// SetActiveSessions sets the current active session count.
+func (m *MetricsCollector) SetActiveSessions(count int64) {
+	m.activeSessions.Store(count)
+}
+
+// SetMemberCount sets the current cluster member count.
+func (m *MetricsCollector) SetMemberCount(count int32) {
+	m.memberCount.Store(count)
+}
+
+// RecordLatency records a latency observation for the given operation.
+func (m *MetricsCollector) RecordLatency(operation string, latency time.Duration) {
+	m.mu.Lock()
+	if m.latencyBuckets[operation] == nil {
+		m.latencyBuckets[operation] = &LatencyBucket{}
+	}
+	bucket := m.latencyBuckets[operation]
+	m.mu.Unlock()
+
+	ms := latency.Milliseconds()
+
+	bucket.mu.Lock()
+	bucket.count++
+	bucket.sum += ms
+
+	// Bucket the latency
+	switch {
+	case ms < 1:
+		bucket.buckets[0]++
+	case ms < 2:
+		bucket.buckets[1]++
+	case ms < 5:
+		bucket.buckets[2]++
+	case ms < 10:
+		bucket.buckets[3]++
+	case ms < 20:
+		bucket.buckets[4]++
+	case ms < 50:
+		bucket.buckets[5]++
+	case ms < 100:
+		bucket.buckets[6]++
+	case ms < 200:
+		bucket.buckets[7]++
+	case ms < 500:
+		bucket.buckets[8]++
+	case ms < 1000:
+		bucket.buckets[9]++
+	case ms < 2000:
+		bucket.buckets[10]++
+	default:
+		bucket.buckets[11]++
+	}
+	bucket.mu.Unlock()
+}
+
+// GetMetrics returns the current metrics as a map.
+func (m *MetricsCollector) GetMetrics() map[string]any {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	latency := make(map[string]any)
+	for name, bucket := range m.latencyBuckets {
+		bucket.mu.RLock()
+		latency[name] = map[string]any{
+			"count":  bucket.count,
+			"avg_ms": float64(bucket.sum) / float64(bucket.count),
+			"p50_ms": m.percentile(bucket, 0.50),
+			"p95_ms": m.percentile(bucket, 0.95),
+			"p99_ms": m.percentile(bucket, 0.99),
+		}
+		bucket.mu.RUnlock()
+	}
+
+	return map[string]any{
+		// Counters
+		"messages_sent":      m.messagesSent.Load(),
+		"messages_received":  m.messagesReceived.Load(),
+		"handoffs_initiated": m.handoffsInitiated.Load(),
+		"handoffs_accepted":  m.handoffsAccepted.Load(),
+		"handoffs_rejected":  m.handoffsRejected.Load(),
+		"handoffs_failed":    m.handoffsFailed.Load(),
+		"elections_won":      m.electionsWon.Load(),
+
+		// NATS counters
+		"nats_published":  m.natsPublished.Load(),
+		"nats_received":   m.natsReceived.Load(),
+		"leader_acquired": m.leaderAcquired.Load(),
+		"leader_lost":     m.leaderLost.Load(),
+
+		// Gauges
+		"load_score":      m.currentLoadScore.Load(),
+		"active_sessions": m.activeSessions.Load(),
+		"member_count":    m.memberCount.Load(),
+
+		// System info
+		"uptime_seconds": time.Since(m.startTime).Seconds(),
+
+		// Latency histograms
+		"latency_ms": latency,
+	}
+}
+
+// percentile calculates an approximate percentile from the bucket data.
+func (m *MetricsCollector) percentile(bucket *LatencyBucket, p float64) float64 {
+	if bucket.count == 0 {
+		return 0
+	}
+
+	target := int64(float64(bucket.count) * p)
+	cumulative := int64(0)
+
+	// Upper bounds for each bucket in ms
+	upperBounds := []int64{1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 1 << 62}
+
+	for i, count := range bucket.buckets {
+		cumulative += count
+		if cumulative >= target {
+			// Return approximate percentile
+			return float64(upperBounds[i])
+		}
+	}
+
+	return 2000.0 // default max
+}
+
+// ExportJSON exports metrics as JSON.
+func (m *MetricsCollector) ExportJSON() ([]byte, error) {
+	return json.MarshalIndent(m.GetMetrics(), "", "  ")
+}
+
+// ExportPrometheus exports metrics in Prometheus text format.
+func (m *MetricsCollector) ExportPrometheus() string {
+	metrics := m.GetMetrics()
+	var out string
+
+	// Counters as Prometheus counters
+	out += "# TYPE picoclaw_messages_sent counter\n"
+	out += fmt.Sprintf("picoclaw_messages_sent %d\n", metrics["messages_sent"])
+
+	out += "\n# TYPE picoclaw_messages_received counter\n"
+	out += fmt.Sprintf("picoclaw_messages_received %d\n", metrics["messages_received"])
+
+	out += "\n# TYPE picoclaw_handoffs_initiated counter\n"
+	out += fmt.Sprintf("picoclaw_handoffs_initiated %d\n", metrics["handoffs_initiated"])
+
+	out += "\n# TYPE picoclaw_handoffs_accepted counter\n"
+	out += fmt.Sprintf("picoclaw_handoffs_accepted %d\n", metrics["handoffs_accepted"])
+
+	out += "\n# TYPE picoclaw_handoffs_rejected counter\n"
+	out += fmt.Sprintf("picoclaw_handoffs_rejected %d\n", metrics["handoffs_rejected"])
+
+	out += "\n# TYPE picoclaw_handoffs_failed counter\n"
+	out += fmt.Sprintf("picoclaw_handoffs_failed %d\n", metrics["handoffs_failed"])
+
+	out += "\n# TYPE picoclaw_elections_won counter\n"
+	out += fmt.Sprintf("picoclaw_elections_won %d\n", metrics["elections_won"])
+
+	// Gauges as Prometheus gauges
+	out += "\n# TYPE picoclaw_load_score gauge\n"
+	out += fmt.Sprintf("picoclaw_load_score %.2f\n", metrics["load_score"])
+
+	out += "\n# TYPE picoclaw_active_sessions gauge\n"
+	out += fmt.Sprintf("picoclaw_active_sessions %d\n", metrics["active_sessions"])
+
+	out += "\n# TYPE picoclaw_member_count gauge\n"
+	out += fmt.Sprintf("picoclaw_member_count %d\n", metrics["member_count"])
+
+	out += "\n# TYPE picoclaw_uptime_seconds gauge\n"
+	out += fmt.Sprintf("picoclaw_uptime_seconds %.0f\n", metrics["uptime_seconds"])
+
+	return out
+}
+
+// Reset resets all metrics (useful for testing).
+func (m *MetricsCollector) Reset() {
+	m.messagesSent.Store(0)
+	m.messagesReceived.Store(0)
+	m.handoffsInitiated.Store(0)
+	m.handoffsAccepted.Store(0)
+	m.handoffsRejected.Store(0)
+	m.handoffsFailed.Store(0)
+	m.electionsWon.Store(0)
+	m.natsPublished.Store(0)
+	m.natsReceived.Store(0)
+	m.leaderAcquired.Store(0)
+	m.leaderLost.Store(0)
+	m.currentLoadScore.Store(0)
+	m.activeSessions.Store(0)
+	m.memberCount.Store(0)
+
+	m.mu.Lock()
+	m.latencyBuckets = make(map[string]*LatencyBucket)
+	m.mu.Unlock()
+	m.startTime = time.Now()
+}

pkg/swarm/nats_membership.go

@@ -0,0 +1,255 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/kv"
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// heartbeatLoop periodically publishes heartbeat and checks for stale nodes.
+func (ds *DiscoveryService) heartbeatLoop() {
+	interval := ds.config.Discovery.HeartbeatInterval.Duration
+	if interval <= 0 {
+		interval = DefaultHeartbeatInterval
+	}
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	// Initial publish
+	ds.publishNode()
+
+	// Start stale node checker
+	go ds.staleNodeChecker(interval)
+
+	for {
+		select {
+		case <-ds.stopChan:
+			return
+		case <-ticker.C:
+			ds.publishNode()
+		}
+	}
+}
+
+// publishNode publishes the local node state to NATS KV.
+func (ds *DiscoveryService) publishNode() {
+	if ds.buckets == nil {
+		return
+	}
+
+	ds.mu.Lock()
+	now := time.Now().UnixNano()
+	ds.localNode.LastHeartbeat = now
+	ds.localNode.Timestamp = now
+	if ds.localNode.FirstSeen == 0 {
+		ds.localNode.FirstSeen = now
+	}
+	ds.localNode.Status = string(NodeStatusAlive)
+	node := *ds.localNode // Copy to avoid holding lock
+	ds.mu.Unlock()
+
+	data, err := json.Marshal(node)
+	if err != nil {
+		logger.ErrorCF("swarm", "failed to marshal node info", map[string]any{"error": err})
+		return
+	}
+
+	if err := ds.buckets.Members.Put(node.ID, data); err != nil {
+		logger.ErrorCF("swarm", "failed to publish node info", map[string]any{"error": err})
+	}
+}
+
+// staleNodeChecker actively checks for stale nodes by reading from KV.
+func (ds *DiscoveryService) staleNodeChecker(interval time.Duration) {
+	checkInterval := interval
+	if checkInterval < 5*time.Second {
+		checkInterval = 5 * time.Second
+	}
+
+	ticker := time.NewTicker(checkInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ds.stopChan:
+			return
+		case <-ticker.C:
+			ds.checkStaleNodes()
+			ds.checkStaleStatusNodes()
+		}
+	}
+}
+
+// checkStaleNodes reads all nodes from KV and removes stale ones.
+func (ds *DiscoveryService) checkStaleNodes() {
+	if ds.buckets == nil {
+		return
+	}
+
+	keys, err := ds.buckets.Members.Keys()
+	if err != nil {
+		return
+	}
+
+	now := time.Now()
+	memberTTL := ds.config.Discovery.MemberTTL.Duration
+	if memberTTL <= 0 {
+		memberTTL = DefaultMemberTTL
+	}
+	timeout := memberTTL * 3 // Use 3x TTL as safety margin
+
+	for _, nodeID := range keys {
+		entry, err := ds.buckets.Members.Get(nodeID)
+		if err != nil {
+			continue
+		}
+		if entry == nil {
+			if nws, ok := ds.membership.GetNode(nodeID); ok {
+				ds.membership.RemoveNode(nodeID)
+				ds.detailedStatus.Remove(nodeID)
+				logger.InfoCF("swarm", "Node removed (stale entry)", map[string]any{"node_id": nodeID})
+				ds.eventHandler.Dispatch(&NodeEvent{
+					Node:  nws.Node,
+					Event: EventLeave,
+					Time:  now.UnixNano(),
+				})
+			}
+			continue
+		}
+
+		var node NodeInfo
+		if err := json.Unmarshal(entry.Value, &node); err != nil {
+			continue
+		}
+
+		// Skip local node
+		if node.ID == ds.localNode.ID {
+			continue
+		}
+
+		lastSeen := node.LastHeartbeat
+		if lastSeen == 0 {
+			lastSeen = node.Timestamp
+		}
+
+		if lastSeen > 0 {
+			age := now.Sub(time.Unix(0, lastSeen))
+			if age > timeout {
+				if nws, ok := ds.membership.GetNode(node.ID); ok {
+					ds.membership.RemoveNode(node.ID)
+					ds.detailedStatus.Remove(node.ID)
+					logger.InfoCF("swarm", "Node marked stale (no heartbeat)", map[string]any{
+						"node_id": node.ID,
+						"age":     age.Seconds(),
+					})
+					ds.eventHandler.Dispatch(&NodeEvent{
+						Node:  nws.Node,
+						Event: EventLeave,
+						Time:  now.UnixNano(),
+					})
+				}
+			}
+		}
+	}
+}
+
+// checkStaleStatusNodes reads all status entries from KV and removes stale ones.
+func (ds *DiscoveryService) checkStaleStatusNodes() {
+	if ds.buckets == nil {
+		return
+	}
+
+	keys, err := ds.buckets.Status.Keys()
+	if err != nil {
+		return
+	}
+
+	now := time.Now()
+	timeout := DefaultDetailedStatusTTL * 2
+
+	for _, nodeID := range keys {
+		entry, err := ds.buckets.Status.Get(nodeID)
+		if err != nil {
+			continue
+		}
+		if entry == nil {
+			ds.detailedStatus.Remove(nodeID)
+			continue
+		}
+
+		var status NodeDetailedInfo
+		if err := json.Unmarshal(entry.Value, &status); err != nil {
+			continue
+		}
+
+		if status.Timestamp > 0 {
+			age := now.Sub(time.Unix(0, status.Timestamp))
+			if age > timeout {
+				ds.detailedStatus.Remove(nodeID)
+				logger.DebugCF("swarm", "Status entry removed (stale)", map[string]any{
+					"node_id": nodeID,
+					"age":     age.Seconds(),
+				})
+			}
+		}
+	}
+}
+
+// watchNodes watches for changes in the membership bucket.
+func (ds *DiscoveryService) watchNodes() {
+	watcher, err := ds.buckets.Members.WatchAll()
+	if err != nil {
+		logger.ErrorCF("swarm", "failed to watch members bucket", map[string]any{"error": err})
+		return
+	}
+	defer watcher.Stop()
+
+	for {
+		select {
+		case <-ds.stopChan:
+			return
+		case entry := <-watcher.Updates():
+			if entry == nil {
+				continue
+			}
+
+			// Bucket isolation: swarm_members bucket only stores node keys
+			// Key format is nodeID directly (no prefix needed since bucket is isolated)
+			nodeID := entry.Key
+
+			// Skip our own entry
+			if nodeID == ds.localNode.ID {
+				continue
+			}
+
+			if entry.Operation == kv.EntryOperationDelete {
+				if nws, ok := ds.membership.GetNode(nodeID); ok {
+					ds.membership.RemoveNode(nodeID)
+					logger.InfoCF("swarm", "Node left (member deleted)", map[string]any{"node_id": nodeID})
+					ds.eventHandler.Dispatch(&NodeEvent{
+						Node:  nws.Node,
+						Event: EventLeave,
+						Time:  time.Now().UnixNano(),
+					})
+				}
+				continue
+			}
+
+			var node NodeInfo
+			if err := json.Unmarshal(entry.Value, &node); err != nil {
+				continue
+			}
+
+			ds.membership.UpdateNode(&node)
+		}
+	}
+}

pkg/swarm/nats_status.go

@@ -0,0 +1,155 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"runtime"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/kv"
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// detailedStatusLoop periodically publishes detailed node status.
+func (ds *DiscoveryService) detailedStatusLoop() {
+	interval := DefaultDetailedStatusInterval
+	hbInterval := ds.config.Discovery.HeartbeatInterval.Duration
+	if hbInterval > 0 {
+		interval = hbInterval * 2
+		if interval < DefaultDetailedStatusInterval {
+			interval = DefaultDetailedStatusInterval
+		}
+	}
+
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+
+	// Initial publish
+	ds.publishDetailedStatus()
+
+	for {
+		select {
+		case <-ds.stopChan:
+			return
+		case <-ticker.C:
+			ds.publishDetailedStatus()
+		}
+	}
+}
+
+// publishDetailedStatus publishes the detailed node status to NATS KV.
+func (ds *DiscoveryService) publishDetailedStatus() {
+	if ds.buckets == nil {
+		return
+	}
+
+	var loadMetrics *LoadMetrics
+	if ds.loadMonitor != nil {
+		loadMetrics = ds.loadMonitor.GetCurrentLoad()
+	} else {
+		loadMetrics = &LoadMetrics{
+			CPUUsage:       0,
+			MemoryUsage:    0,
+			MemoryBytes:    0,
+			Goroutines:     runtime.NumGoroutine(),
+			ActiveSessions: 0,
+			Score:          0,
+		}
+	}
+
+	status := BuildDetailedStatus(
+		ds.localNode.ID,
+		ds.localNode.Addr,
+		ds.localNode.Port,
+		0, // No HTTP port; all communication via NATS
+		ds.localNode.LoadScore,
+		loadMetrics,
+		ds.getTodoList(),
+		ds.getActiveTasks(),
+		ds.startTime,
+		ds.getLastError(),
+		ds.version,
+	)
+
+	// Update local registry
+	ds.detailedStatus.Update(status)
+
+	// Publish to NATS KV
+	data, err := json.Marshal(status)
+	if err != nil {
+		logger.ErrorCF("swarm", "failed to marshal detailed status", map[string]any{"error": err})
+		return
+	}
+
+	if err := ds.buckets.Status.Put(status.ID, data); err != nil {
+		logger.ErrorCF("swarm", "failed to publish detailed status", map[string]any{"error": err})
+	}
+}
+
+// watchDetailedStatus watches for detailed status updates from other nodes.
+func (ds *DiscoveryService) watchDetailedStatus() {
+	if ds.buckets == nil {
+		return
+	}
+
+	watcher, err := ds.buckets.Status.WatchAll()
+	if err != nil {
+		logger.ErrorCF("swarm", "failed to watch status bucket", map[string]any{"error": err})
+		return
+	}
+	defer watcher.Stop()
+
+	for {
+		select {
+		case <-ds.stopChan:
+			return
+		case entry := <-watcher.Updates():
+			if entry == nil {
+				continue
+			}
+
+			// Bucket isolation: swarm_status bucket only stores status keys
+			// Key format is nodeID directly (no prefix needed since bucket is isolated)
+			nodeID := entry.Key
+
+			// Skip our own entry
+			if nodeID == ds.localNode.ID {
+				continue
+			}
+
+			if entry.Operation == kv.EntryOperationDelete {
+				ds.detailedStatus.Remove(nodeID)
+				continue
+			}
+
+			var status NodeDetailedInfo
+			if err := json.Unmarshal(entry.Value, &status); err != nil {
+				continue
+			}
+
+			ds.detailedStatus.Update(&status)
+		}
+	}
+}
+
+// SetLoadMonitor sets the load monitor for detailed status reporting.
+func (ds *DiscoveryService) SetLoadMonitor(lm *LoadMonitor) {
+	ds.loadMonitor = lm
+}
+
+// SetVersion sets the version string for detailed status.
+func (ds *DiscoveryService) SetVersion(version string) {
+	ds.mu.Lock()
+	ds.version = version
+	ds.mu.Unlock()
+}
+
+// GetDetailedStatus returns the detailed status registry.
+func (ds *DiscoveryService) GetDetailedStatus() *NodeDetailedStatus {
+	return ds.detailedStatus
+}

pkg/swarm/node.go

@@ -0,0 +1,350 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+)
+
+// NodeInfo represents a node in the swarm cluster.
+type NodeInfo struct {
+	ID        string            `json:"id"`         // Unique node identifier
+	Addr      string            `json:"addr"`       // Listening address
+	Port      int               `json:"port"`       // RPC port
+	AgentCaps map[string]string `json:"agent_caps"` // Agent capabilities {agent_id: capability}
+	LoadScore float64           `json:"load_score"` // Load score 0-1
+	Labels    map[string]string `json:"labels"`     // Custom labels
+	Version   string            `json:"version"`    // PicoClaw version
+
+	// Heartbeat fields for liveness detection
+	LastHeartbeat int64  `json:"last_heartbeat"` // Last heartbeat time (Unix nano)
+	FirstSeen     int64  `json:"first_seen"`     // When this node was first discovered
+	Status        string `json:"status"`         // Current status: "alive", "suspect", "dead", "left"
+
+	// Deprecated: Use LastHeartbeat instead
+	Timestamp int64 `json:"timestamp"` // Last update time (Unix nano) - for backward compatibility
+}
+
+// IsAlive checks if the node is considered alive based on heartbeat.
+func (n *NodeInfo) IsAlive(timeout time.Duration) bool {
+	// Prefer LastHeartbeat, fall back to Timestamp for backward compatibility
+	lastSeen := n.LastHeartbeat
+	if lastSeen == 0 {
+		lastSeen = n.Timestamp
+	}
+	if lastSeen == 0 {
+		return false
+	}
+	age := time.Since(time.Unix(0, lastSeen))
+	return age < timeout
+}
+
+// GetLastSeen returns the last seen time (heartbeat or timestamp).
+func (n *NodeInfo) GetLastSeen() time.Time {
+	lastSeen := n.LastHeartbeat
+	if lastSeen == 0 {
+		lastSeen = n.Timestamp
+	}
+	return time.Unix(0, lastSeen)
+}
+
+// String returns a JSON representation of the node.
+func (n *NodeInfo) String() string {
+	data, _ := json.Marshal(n)
+	return string(data)
+}
+
+// GetAddress returns the full address (host:port) for RPC communication.
+func (n *NodeInfo) GetAddress() string {
+	if n.Port > 0 {
+		return fmt.Sprintf("%s:%d", n.Addr, n.Port)
+	}
+	return n.Addr
+}
+
+// NodeStatus represents the current status of a node.
+type NodeStatus string
+
+const (
+	NodeStatusAlive   NodeStatus = "alive"
+	NodeStatusSuspect NodeStatus = "suspect"
+	NodeStatusDead    NodeStatus = "dead"
+	NodeStatusLeft    NodeStatus = "left"
+)
+
+// NodeState represents the state of a node in the membership view.
+type NodeState struct {
+	Node        *NodeInfo  `json:"node"`
+	Status      NodeStatus `json:"status"`
+	StatusSince int64      `json:"status_since"` // Unix nano when status was set
+	LastSeen    int64      `json:"last_seen"`    // Unix nano of last sighting
+	LastPing    int64      `json:"last_ping"`    // Unix nano of last successful ping
+	PingSuccess int        `json:"ping_success"` // Consecutive successful pings
+	PingFailure int        `json:"ping_failure"` // Consecutive failed pings
+}
+
+// IsAvailable returns true if the node is available for handoff.
+func (ns *NodeState) IsAvailable() bool {
+	return ns.Status == NodeStatusAlive && ns.Node.LoadScore < DefaultAvailableLoadThreshold
+}
+
+// UpdateStatus updates the node status with timestamp.
+func (ns *NodeState) UpdateStatus(status NodeStatus) {
+	ns.Status = status
+	ns.StatusSince = time.Now().UnixNano()
+}
+
+// NodeEvent represents a node state change event.
+type NodeEvent struct {
+	Node  *NodeInfo `json:"node"`
+	Event EventType `json:"event"`
+	Time  int64     `json:"time"`
+}
+
+// EventType represents the type of node event.
+type EventType string
+
+const (
+	EventJoin   EventType = "join"
+	EventLeave  EventType = "leave"
+	EventUpdate EventType = "update"
+)
+
+// EventHandler is a callback function for node events.
+type EventHandler func(*NodeEvent)
+
+// EventHandlerID is a unique identifier for a subscribed handler.
+type EventHandlerID int
+
+// EventDispatcher manages event handlers.
+type EventDispatcher struct {
+	handlers []EventHandler
+	mu       sync.RWMutex
+	nextID   EventHandlerID
+	ids      map[EventHandlerID]int // handler ID -> index in handlers slice
+}
+
+// NewEventDispatcher creates a new event dispatcher.
+func NewEventDispatcher() *EventDispatcher {
+	return &EventDispatcher{
+		handlers: make([]EventHandler, 0),
+		ids:      make(map[EventHandlerID]int),
+		nextID:   1,
+	}
+}
+
+// Subscribe adds a new event handler and returns its ID.
+func (ed *EventDispatcher) Subscribe(handler EventHandler) EventHandlerID {
+	ed.mu.Lock()
+	defer ed.mu.Unlock()
+
+	id := ed.nextID
+	ed.nextID++
+
+	ed.handlers = append(ed.handlers, handler)
+	ed.ids[id] = len(ed.handlers) - 1
+	return id
+}
+
+// Unsubscribe removes an event handler by ID.
+func (ed *EventDispatcher) Unsubscribe(id EventHandlerID) {
+	ed.mu.Lock()
+	defer ed.mu.Unlock()
+
+	idx, ok := ed.ids[id]
+	if !ok {
+		return
+	}
+
+	// Remove handler
+	ed.handlers = append(ed.handlers[:idx], ed.handlers[idx+1:]...)
+
+	// Update indices
+	delete(ed.ids, id)
+	for handlerID, handlerIdx := range ed.ids {
+		if handlerIdx > idx {
+			ed.ids[handlerID] = handlerIdx - 1
+		}
+	}
+}
+
+// Dispatch sends an event to all registered handlers.
+func (ed *EventDispatcher) Dispatch(event *NodeEvent) {
+	ed.DispatchContext(event, nil)
+}
+
+// DispatchContext sends an event to all registered handlers with context cancellation support.
+func (ed *EventDispatcher) DispatchContext(event *NodeEvent, ctx context.Context) {
+	ed.mu.RLock()
+	handlers := make([]EventHandler, len(ed.handlers))
+	copy(handlers, ed.handlers)
+	ed.mu.RUnlock()
+
+	for _, handler := range handlers {
+		// Run handlers in goroutines to avoid blocking
+		go func(h EventHandler) {
+			defer func() {
+				if r := recover(); r != nil {
+					logger.ErrorCF("swarm", "handler panic recovered", map[string]any{"panic": r})
+				}
+			}()
+
+			// Check if context is canceled
+			if ctx != nil {
+				select {
+				case <-ctx.Done():
+					logger.DebugC("swarm", "handler skipped due to context cancellation")
+					return
+				default:
+				}
+			}
+
+			h(event)
+		}(handler)
+	}
+}
+
+// NodeStats tracks statistics about a node.
+type NodeStats struct {
+	MessagesSent      int64     `json:"messages_sent"`
+	MessagesReceived  int64     `json:"messages_received"`
+	HandoffsAccepted  int       `json:"handoffs_accepted"`
+	HandoffsInitiated int       `json:"handoffs_initiated"`
+	LastError         string    `json:"last_error,omitempty"`
+	LastErrorTime     time.Time `json:"last_error_time,omitempty"`
+	UptimeStart       time.Time `json:"uptime_start"`
+}
+
+// NodeWithState combines a node with its state and stats.
+type NodeWithState struct {
+	Node  *NodeInfo  `json:"node"`
+	State *NodeState `json:"state"`
+	Stats *NodeStats `json:"stats,omitempty"`
+}
+
+// IsAvailable returns true if the node is available for handoff.
+func (nws *NodeWithState) IsAvailable() bool {
+	if nws.State == nil || nws.Node == nil {
+		return false
+	}
+	return nws.State.Status == NodeStatusAlive && nws.Node.LoadScore < DefaultAvailableLoadThreshold
+}
+
+// ClusterView represents the current view of the cluster.
+type ClusterView struct {
+	Nodes       map[string]*NodeWithState `json:"nodes"`
+	LocalNodeID string                    `json:"local_node_id"`
+	Size        int                       `json:"size"`
+	Version     int64                     `json:"version"` // View version for conflict detection
+	mu          sync.RWMutex
+}
+
+// NewClusterView creates a new cluster view.
+func NewClusterView(localNodeID string) *ClusterView {
+	return &ClusterView{
+		Nodes:       make(map[string]*NodeWithState),
+		LocalNodeID: localNodeID,
+		Version:     time.Now().UnixNano(),
+	}
+}
+
+// AddOrUpdate adds or updates a node in the view.
+func (cv *ClusterView) AddOrUpdate(node *NodeInfo) *NodeWithState {
+	cv.mu.Lock()
+	defer cv.mu.Unlock()
+
+	cv.Version++
+
+	existing, ok := cv.Nodes[node.ID]
+	if ok {
+		// Update existing node
+		existing.Node = node
+		return existing
+	}
+
+	// Add new node
+	nws := &NodeWithState{
+		Node: node,
+		State: &NodeState{
+			Node:        node,
+			Status:      NodeStatusAlive,
+			StatusSince: time.Now().UnixNano(),
+			LastSeen:    time.Now().UnixNano(),
+		},
+		Stats: &NodeStats{
+			UptimeStart: time.Now(),
+		},
+	}
+	cv.Nodes[node.ID] = nws
+	cv.Size = len(cv.Nodes)
+	return nws
+}
+
+// Remove removes a node from the view.
+func (cv *ClusterView) Remove(nodeID string) {
+	cv.mu.Lock()
+	defer cv.mu.Unlock()
+
+	cv.Version++
+	delete(cv.Nodes, nodeID)
+	cv.Size = len(cv.Nodes)
+}
+
+// Get retrieves a node from the view.
+func (cv *ClusterView) Get(nodeID string) (*NodeWithState, bool) {
+	cv.mu.RLock()
+	defer cv.mu.RUnlock()
+
+	nws, ok := cv.Nodes[nodeID]
+	return nws, ok
+}
+
+// List returns all nodes in the view.
+func (cv *ClusterView) List() []*NodeWithState {
+	cv.mu.RLock()
+	defer cv.mu.RUnlock()
+
+	result := make([]*NodeWithState, 0, len(cv.Nodes))
+	for _, nws := range cv.Nodes {
+		result = append(result, nws)
+	}
+	return result
+}
+
+// GetAliveNodes returns all alive nodes.
+func (cv *ClusterView) GetAliveNodes() []*NodeWithState {
+	cv.mu.RLock()
+	defer cv.mu.RUnlock()
+
+	result := make([]*NodeWithState, 0)
+	for _, nws := range cv.Nodes {
+		if nws.State.Status == NodeStatusAlive {
+			result = append(result, nws)
+		}
+	}
+	return result
+}
+
+// GetAvailableNodes returns all available nodes (alive and not overloaded).
+func (cv *ClusterView) GetAvailableNodes() []*NodeWithState {
+	cv.mu.RLock()
+	defer cv.mu.RUnlock()
+
+	result := make([]*NodeWithState, 0)
+	for _, nws := range cv.Nodes {
+		if nws.IsAvailable() {
+			result = append(result, nws)
+		}
+	}
+	return result
+}

pkg/swarm/node_discovery_interface.go

@@ -0,0 +1,41 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+// NodeDiscovery provides node discovery and membership tracking.
+//
+// This is the minimal interface for discovering other nodes in the swarm.
+// Implementations can use NATS KV, etcd, Consul, or any other coordination service.
+type NodeDiscovery interface {
+	// Start starts the discovery service.
+	Start() error
+
+	// Stop stops the discovery service.
+	Stop() error
+
+	// AliveNodes returns the current list of alive nodes.
+	// This is a point-in-time snapshot.
+	AliveNodes() []*NodeInfo
+
+	// WatchNodes registers a callback for cluster view changes.
+	// The callback receives the updated view and should return quickly.
+	// Returns a function that can be called to cancel the watch.
+	WatchNodes(callback func(View)) func()
+}
+
+// NodeInfoUpdater allows updating local node information.
+// This is an optional interface that NodeDiscovery implementations may implement.
+type NodeInfoUpdater interface {
+	// UpdateLocalInfo updates the local node's information.
+	UpdateLocalInfo(info *NodeInfo)
+
+	// UpdateLoad updates the local node's load score.
+	UpdateLoad(score float64)
+
+	// UpdateCapabilities updates the local node's agent capabilities.
+	UpdateCapabilities(caps map[string]string)
+}

pkg/swarm/node_status.go

@@ -0,0 +1,182 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"runtime"
+	"sync"
+	"time"
+)
+
+// NodeDetailedInfo represents detailed status information about a node.
+// This is periodically written to NATS KV for fast status queries without
+// needing to send requests to other nodes.
+type NodeDetailedInfo struct {
+	// Basic node info
+	ID        string  `json:"id"`
+	Addr      string  `json:"addr"`
+	Port      int     `json:"port"`
+	HTTPPort  int     `json:"http_port"`
+	LoadScore float64 `json:"load_score"`
+	Timestamp int64   `json:"timestamp"`
+
+	// Load metrics
+	CPUUsage       float64 `json:"cpu_usage"`
+	MemoryUsage    float64 `json:"memory_usage"`
+	MemoryBytes    uint64  `json:"memory_bytes"`
+	Goroutines     int     `json:"goroutines"`
+	ActiveSessions int     `json:"active_sessions"`
+
+	// Task information
+	TodoList    []string `json:"todo_list,omitempty"`
+	ActiveTasks int      `json:"active_tasks"`
+
+	// System information
+	DiskUsagePercent float64 `json:"disk_usage_percent,omitempty"`
+	DiskUsedBytes    uint64  `json:"disk_used_bytes,omitempty"`
+	DiskTotalBytes   uint64  `json:"disk_total_bytes,omitempty"`
+
+	// Status
+	LastError string `json:"last_error,omitempty"`
+	Uptime    int64  `json:"uptime"`     // Uptime in seconds
+	Status    string `json:"status"`     // "alive", "suspect", "dead"
+	Version   string `json:"version"`    // PicoClaw version
+	GoVersion string `json:"go_version"` // Go runtime version
+	OS        string `json:"os"`         // Operating system
+	Arch      string `json:"arch"`       // Architecture
+}
+
+// NodeDetailedStatus is a registry for node detailed status from NATS KV.
+// It caches the latest status from all nodes for fast queries.
+type NodeDetailedStatus struct {
+	statusMap map[string]*NodeDetailedInfo // node_id -> status
+	mu        sync.RWMutex
+}
+
+// NewNodeDetailedStatus creates a new node detailed status registry.
+func NewNodeDetailedStatus() *NodeDetailedStatus {
+	return &NodeDetailedStatus{
+		statusMap: make(map[string]*NodeDetailedInfo),
+	}
+}
+
+// Update updates the status for a node.
+func (nds *NodeDetailedStatus) Update(status *NodeDetailedInfo) {
+	nds.mu.Lock()
+	defer nds.mu.Unlock()
+	nds.statusMap[status.ID] = status
+}
+
+// Get returns the status for a node.
+func (nds *NodeDetailedStatus) Get(nodeID string) (*NodeDetailedInfo, bool) {
+	nds.mu.RLock()
+	defer nds.mu.RUnlock()
+	s, ok := nds.statusMap[nodeID]
+	return s, ok
+}
+
+// GetAll returns all node statuses.
+func (nds *NodeDetailedStatus) GetAll() []*NodeDetailedInfo {
+	nds.mu.RLock()
+	defer nds.mu.RUnlock()
+
+	result := make([]*NodeDetailedInfo, 0, len(nds.statusMap))
+	for _, s := range nds.statusMap {
+		result = append(result, s)
+	}
+	return result
+}
+
+// Remove removes a node from the registry.
+func (nds *NodeDetailedStatus) Remove(nodeID string) {
+	nds.mu.Lock()
+	defer nds.mu.Unlock()
+	delete(nds.statusMap, nodeID)
+}
+
+// CleanExpired removes statuses older than the given TTL.
+func (nds *NodeDetailedStatus) CleanExpired(ttl time.Duration) {
+	nds.mu.Lock()
+	defer nds.mu.Unlock()
+
+	cutoff := time.Now().Add(-ttl).UnixNano()
+	for id, s := range nds.statusMap {
+		if s.Timestamp < cutoff {
+			delete(nds.statusMap, id)
+		}
+	}
+}
+
+// AsMap returns the status map for external access.
+func (nds *NodeDetailedStatus) AsMap() map[string]*NodeDetailedInfo {
+	nds.mu.RLock()
+	defer nds.mu.RUnlock()
+
+	result := make(map[string]*NodeDetailedInfo, len(nds.statusMap))
+	for k, v := range nds.statusMap {
+		result[k] = v
+	}
+	return result
+}
+
+// MarshalJSON implements json.Marshaler.
+func (nds *NodeDetailedStatus) MarshalJSON() ([]byte, error) {
+	nds.mu.RLock()
+	defer nds.mu.RUnlock()
+	return json.Marshal(nds.statusMap)
+}
+
+// BuildDetailedStatus builds a NodeDetailedInfo from the current node state.
+func BuildDetailedStatus(
+	nodeID, addr string,
+	port, httpPort int,
+	loadScore float64,
+	loadMetrics *LoadMetrics,
+	todoList []string,
+	activeTasks int,
+	startTime time.Time,
+	lastError string,
+	version string,
+) *NodeDetailedInfo {
+	uptime := time.Since(startTime)
+
+	status := &NodeDetailedInfo{
+		ID:        nodeID,
+		Addr:      addr,
+		Port:      port,
+		HTTPPort:  httpPort,
+		LoadScore: loadScore,
+		Timestamp: time.Now().UnixNano(),
+
+		CPUUsage:       loadMetrics.CPUUsage,
+		MemoryUsage:    loadMetrics.MemoryUsage,
+		MemoryBytes:    loadMetrics.MemoryBytes,
+		Goroutines:     loadMetrics.Goroutines,
+		ActiveSessions: loadMetrics.ActiveSessions,
+
+		TodoList:    todoList,
+		ActiveTasks: activeTasks,
+
+		LastError: lastError,
+		Uptime:    int64(uptime.Seconds()),
+		Status:    string(NodeStatusAlive),
+		Version:   version,
+		GoVersion: runtime.Version(),
+		OS:        runtime.GOOS,
+		Arch:      runtime.GOARCH,
+	}
+
+	return status
+}
+
+// GetMemoryBytes returns the current memory allocation in bytes.
+func (lm *LoadMetrics) GetMemoryBytes() uint64 {
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	return m.Alloc
+}

pkg/swarm/nonce.go

@@ -0,0 +1,113 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm nonce cache for replay attack prevention
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"sync"
+	"time"
+)
+
+// NonceCache tracks seen nonces for replay attack prevention.
+// Uses a simple ring buffer with TTL-based expiration.
+type NonceCache struct {
+	mu       sync.RWMutex
+	entries  map[string]*nonceEntry
+	ring     []*nonceEntry
+	ringIdx  int
+	ringSize int
+	ttl      time.Duration
+}
+
+type nonceEntry struct {
+	nonce     string
+	timestamp time.Time
+	nodeID    string
+}
+
+// NewNonceCache creates a new nonce cache.
+func NewNonceCache(ttl time.Duration, ringSize int) *NonceCache {
+	if ringSize <= 0 {
+		ringSize = 1000 // Default ring size
+	}
+	return &NonceCache{
+		entries:  make(map[string]*nonceEntry),
+		ring:     make([]*nonceEntry, ringSize),
+		ringSize: ringSize,
+		ringIdx:  0,
+		ttl:      ttl,
+	}
+}
+
+// CheckAndAdd returns true if the nonce is new (adds it), false if already seen.
+func (nc *NonceCache) CheckAndAdd(nonce, nodeID string) bool {
+	if nonce == "" {
+		return false // Empty nonce is invalid
+	}
+
+	key := nodeID + ":" + nonce
+
+	// Fast path: check map
+	nc.mu.RLock()
+	if _, exists := nc.entries[key]; exists {
+		nc.mu.RUnlock()
+		return false
+	}
+	nc.mu.RUnlock()
+
+	// Slow path: add to cache
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+
+	// Double-check after acquiring write lock
+	if _, exists := nc.entries[key]; exists {
+		return false
+	}
+
+	// Clean up old entry at current ring position
+	if oldEntry := nc.ring[nc.ringIdx]; oldEntry != nil {
+		oldKey := oldEntry.nodeID + ":" + oldEntry.nonce
+		delete(nc.entries, oldKey)
+	}
+
+	// Add new entry
+	entry := &nonceEntry{
+		nonce:     nonce,
+		timestamp: time.Now(),
+		nodeID:    nodeID,
+	}
+	nc.entries[key] = entry
+	nc.ring[nc.ringIdx] = entry
+	nc.ringIdx = (nc.ringIdx + 1) % nc.ringSize
+
+	return true
+}
+
+// Cleanup removes expired entries older than TTL.
+// Should be called periodically (e.g., every minute).
+func (nc *NonceCache) Cleanup() {
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+
+	cutoff := time.Now().Add(-nc.ttl)
+	for key, entry := range nc.entries {
+		if entry.timestamp.Before(cutoff) {
+			delete(nc.entries, key)
+		}
+	}
+}
+
+// Stats returns cache statistics.
+func (nc *NonceCache) Stats() map[string]any {
+	nc.mu.RLock()
+	defer nc.mu.RUnlock()
+
+	return map[string]any{
+		"size":        len(nc.entries),
+		"ring_size":   nc.ringSize,
+		"ttl_seconds": nc.ttl.Seconds(),
+	}
+}

pkg/swarm/policy.go

@@ -0,0 +1,203 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm failure mode policies for graceful degradation
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"sync"
+	"time"
+)
+
+// FailurePolicy defines how the system behaves when failures occur.
+type FailurePolicy struct {
+	// TimeoutStrategy defines what to do on request-reply timeout.
+	TimeoutStrategy TimeoutStrategy `json:"timeout_strategy"`
+
+	// OverloadCooldown is how long to avoid a node after it's overloaded.
+	OverloadCooldown Duration `json:"overload_cooldown"`
+
+	// MaxConsecutiveFailures before circuit breaker opens.
+	MaxConsecutiveFailures int `json:"max_consecutive_failures"`
+
+	// CircuitBreakerCooldown is how long to wait before retrying a failed node.
+	CircuitBreakerCooldown Duration `json:"circuit_breaker_cooldown"`
+}
+
+// TimeoutStrategy defines timeout fallback behavior.
+type TimeoutStrategy string
+
+const (
+	// TimeoutFallbackLocal: fall back to local processing on timeout.
+	TimeoutFallbackLocal TimeoutStrategy = "fallback_local"
+	// TimeoutRetry: retry with another node on timeout.
+	TimeoutRetry TimeoutStrategy = "retry"
+	// TimeoutFail: return error to user on timeout.
+	TimeoutFail TimeoutStrategy = "fail"
+)
+
+// DefaultFailurePolicy returns the default failure policy.
+func DefaultFailurePolicy() *FailurePolicy {
+	return &FailurePolicy{
+		TimeoutStrategy:        TimeoutFallbackLocal,
+		OverloadCooldown:       Duration{30 * time.Second},
+		MaxConsecutiveFailures: 3,
+		CircuitBreakerCooldown: Duration{60 * time.Second},
+	}
+}
+
+// CircuitBreaker tracks node health and opens/closes circuits.
+type CircuitBreaker struct {
+	mu       sync.RWMutex
+	nodes    map[string]*nodeState
+	cooldown time.Duration
+	maxFails int
+}
+
+type nodeState struct {
+	consecutiveFails int
+	lastFailTime     time.Time
+	state            CircuitState
+}
+
+// CircuitState represents the circuit breaker state.
+type CircuitState string
+
+const (
+	CircuitClosed   CircuitState = "closed"    // Normal operation
+	CircuitOpen     CircuitState = "open"      // Failing, stop sending
+	CircuitHalfOpen CircuitState = "half-open" // Testing if recovered
+)
+
+// NewCircuitBreaker creates a new circuit breaker.
+func NewCircuitBreaker(maxFails int, cooldown time.Duration) *CircuitBreaker {
+	return &CircuitBreaker{
+		nodes:    make(map[string]*nodeState),
+		cooldown: cooldown,
+		maxFails: maxFails,
+	}
+}
+
+// CanProceed returns true if requests can proceed to the node.
+func (cb *CircuitBreaker) CanProceed(nodeID string) bool {
+	cb.mu.RLock()
+	defer cb.mu.RUnlock()
+
+	state, exists := cb.nodes[nodeID]
+	if !exists {
+		return true
+	}
+
+	// Check if circuit should be half-open (cooldown expired)
+	if state.state == CircuitOpen && time.Since(state.lastFailTime) > cb.cooldown {
+		return true // Allow one request to test
+	}
+
+	return state.state != CircuitOpen
+}
+
+// RecordSuccess records a successful request.
+func (cb *CircuitBreaker) RecordSuccess(nodeID string) {
+	cb.mu.Lock()
+	defer cb.mu.Unlock()
+
+	if state, exists := cb.nodes[nodeID]; exists {
+		state.consecutiveFails = 0
+		if state.state == CircuitHalfOpen {
+			state.state = CircuitClosed
+		}
+	}
+}
+
+// RecordFailure records a failed request.
+func (cb *CircuitBreaker) RecordFailure(nodeID string) {
+	cb.mu.Lock()
+	defer cb.mu.Unlock()
+
+	state := cb.nodes[nodeID]
+	if state == nil {
+		state = &nodeState{}
+		cb.nodes[nodeID] = state
+	}
+
+	state.consecutiveFails++
+	state.lastFailTime = time.Now()
+
+	if state.consecutiveFails >= cb.maxFails {
+		state.state = CircuitOpen
+	}
+}
+
+// GetState returns the current state of a node.
+func (cb *CircuitBreaker) GetState(nodeID string) CircuitState {
+	cb.mu.RLock()
+	defer cb.mu.RUnlock()
+
+	if state, exists := cb.nodes[nodeID]; exists {
+		// Check if cooldown expired
+		if state.state == CircuitOpen && time.Since(state.lastFailTime) > cb.cooldown {
+			return CircuitHalfOpen
+		}
+		return state.state
+	}
+	return CircuitClosed
+}
+
+// NodeCooldown tracks overloaded nodes to prevent oscillation.
+type NodeCooldown struct {
+	mu     sync.RWMutex
+	cooled map[string]time.Time
+	ttl    time.Duration
+}
+
+// NewNodeCooldown creates a new cooldown tracker.
+func NewNodeCooldown(ttl time.Duration) *NodeCooldown {
+	return &NodeCooldown{
+		cooled: make(map[string]time.Time),
+		ttl:    ttl,
+	}
+}
+
+// IsCooled returns true if the node is in cooldown period.
+func (nc *NodeCooldown) IsCooled(nodeID string) bool {
+	nc.mu.RLock()
+	defer nc.mu.RUnlock()
+
+	if t, exists := nc.cooled[nodeID]; exists {
+		if time.Since(t) < nc.ttl {
+			return true
+		}
+	}
+	return false
+}
+
+// Add puts a node into cooldown.
+func (nc *NodeCooldown) Add(nodeID string) {
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+
+	nc.cooled[nodeID] = time.Now()
+}
+
+// Remove removes a node from cooldown (e.g., after successful request).
+func (nc *NodeCooldown) Remove(nodeID string) {
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+
+	delete(nc.cooled, nodeID)
+}
+
+// Cleanup removes expired entries.
+func (nc *NodeCooldown) Cleanup() {
+	nc.mu.Lock()
+	defer nc.mu.Unlock()
+
+	now := time.Now()
+	for nodeID, t := range nc.cooled {
+		if now.Sub(t) >= nc.ttl {
+			delete(nc.cooled, nodeID)
+		}
+	}
+}

pkg/swarm/router_default.go

@@ -0,0 +1,88 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import "fmt"
+
+// DefaultRouter implements the Router interface with load-based routing.
+type DefaultRouter struct {
+	config HandoffConfig
+}
+
+// NewDefaultRouter creates a new default router.
+func NewDefaultRouter(config HandoffConfig) *DefaultRouter {
+	return &DefaultRouter{config: config}
+}
+
+// PickNode selects a node for the given task.
+func (r *DefaultRouter) PickNode(task Task, view View) RoutingDecision {
+	// Filter available nodes based on capabilities
+	var candidates []*NodeInfo
+	if len(task.RequiredCaps) > 0 {
+		// Need to filter by capabilities
+		candidates = r.filterByCapability(view.AliveNodes(), task.RequiredCaps)
+	} else {
+		candidates = view.AliveNodes()
+	}
+
+	if len(candidates) == 0 {
+		return RoutingDecision{
+			Reject: true,
+			Reason: "no available nodes with required capabilities",
+		}
+	}
+
+	// Select least loaded node
+	selected := candidates[0]
+	for _, n := range candidates[1:] {
+		if n.LoadScore < selected.LoadScore {
+			selected = n
+		}
+	}
+
+	return RoutingDecision{
+		NodeID: selected.ID,
+		Reason: fmt.Sprintf("least loaded node (load: %.2f)", selected.LoadScore),
+	}
+}
+
+// CanHandleLocally checks if the local node can handle the given task.
+func (r *DefaultRouter) CanHandleLocally(task Task, localLoad float64) bool {
+	// Check load threshold
+	if localLoad > r.config.LoadThreshold {
+		return false
+	}
+
+	// For capability checking, we'd need to access local node caps
+	// This is handled by the caller in most cases
+	return true
+}
+
+// filterByCapability filters nodes that have all required capabilities.
+func (r *DefaultRouter) filterByCapability(nodes []*NodeInfo, requiredCaps []string) []*NodeInfo {
+	result := make([]*NodeInfo, 0)
+	for _, n := range nodes {
+		hasAll := true
+		for _, cap := range requiredCaps {
+			found := false
+			for _, nodeCap := range n.AgentCaps {
+				if nodeCap == cap {
+					found = true
+					break
+				}
+			}
+			if !found {
+				hasAll = false
+				break
+			}
+		}
+		if hasAll {
+			result = append(result, n)
+		}
+	}
+	return result
+}

pkg/swarm/router_interface.go

@@ -0,0 +1,39 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+// Task represents a task that needs to be routed to a node.
+type Task struct {
+	ID           string            `json:"id"`
+	Type         string            `json:"type"`
+	RequiredCaps []string          `json:"required_caps,omitempty"` // Required agent capabilities
+	Priority     int               `json:"priority,omitempty"`
+	Metadata     map[string]any    `json:"metadata,omitempty"`
+	Context      map[string]string `json:"context,omitempty"`
+}
+
+// RoutingDecision is the result of routing a task.
+type RoutingDecision struct {
+	NodeID      string `json:"node_id"`                 // Selected node ID
+	Reason      string `json:"reason,omitempty"`        // Why this node was selected
+	Reject      bool   `json:"reject,omitempty"`        // true if request should be rejected (no nodes available)
+	LoadTooHigh bool   `json:"load_too_high,omitempty"` // true if local load is too high to accept
+}
+
+// Router provides task routing decisions based on cluster view.
+//
+// The router selects the best node for a task based on load,
+// capabilities, and other routing policies.
+type Router interface {
+	// PickNode selects a node for the given task.
+	// Returns a RoutingDecision with the selected node and reason.
+	PickNode(task Task, view View) RoutingDecision
+
+	// CanHandleLocally checks if the local node can handle the given task.
+	// Returns false if the local node is overloaded or missing capabilities.
+	CanHandleLocally(task Task, localLoad float64) bool
+}

pkg/swarm/swarm_test.go

@@ -0,0 +1,315 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNodeInfo(t *testing.T) {
+	node := &NodeInfo{
+		ID:        "test-node-1",
+		Addr:      "192.168.1.100",
+		Port:      7947,
+		LoadScore: 0.5,
+		AgentCaps: map[string]string{
+			"agent-1": "general",
+		},
+		Labels: map[string]string{
+			"region": "us-west",
+		},
+		Timestamp: time.Now().UnixNano(),
+	}
+
+	t.Run("IsAlive", func(t *testing.T) {
+		assert.True(t, node.IsAlive(time.Minute))
+		assert.False(t, node.IsAlive(time.Nanosecond))
+	})
+
+	t.Run("GetAddress", func(t *testing.T) {
+		addr := node.GetAddress()
+		assert.Equal(t, "192.168.1.100:7947", addr)
+	})
+}
+
+func TestClusterView(t *testing.T) {
+	view := NewClusterView("local-node")
+
+	t.Run("AddOrUpdate", func(t *testing.T) {
+		node := &NodeInfo{
+			ID:        "node-1",
+			Addr:      "192.168.1.1",
+			Port:      7947,
+			LoadScore: 0.3,
+			Timestamp: time.Now().UnixNano(),
+		}
+
+		nws := view.AddOrUpdate(node)
+		require.NotNil(t, nws)
+		assert.Equal(t, node.ID, nws.Node.ID)
+		assert.Equal(t, 1, view.Size)
+	})
+
+	t.Run("Get", func(t *testing.T) {
+		node, ok := view.Get("node-1")
+		assert.True(t, ok)
+		assert.Equal(t, "node-1", node.Node.ID)
+
+		_, ok = view.Get("non-existent")
+		assert.False(t, ok)
+	})
+
+	t.Run("GetAliveNodes", func(t *testing.T) {
+		nodes := view.GetAliveNodes()
+		assert.Equal(t, 1, len(nodes))
+	})
+
+	t.Run("GetAvailableNodes", func(t *testing.T) {
+		nodes := view.GetAvailableNodes()
+		assert.Equal(t, 1, len(nodes)) // 0.3 < 0.9
+	})
+
+	t.Run("Remove", func(t *testing.T) {
+		view.Remove("node-1")
+		assert.Equal(t, 0, view.Size)
+	})
+}
+
+func TestLoadMonitor(t *testing.T) {
+	config := &LoadMonitorConfig{
+		Enabled:       true,
+		Interval:      Duration{time.Second},
+		SampleSize:    10,
+		CPUWeight:     0.3,
+		MemoryWeight:  0.3,
+		SessionWeight: 0.4,
+	}
+
+	monitor := NewLoadMonitor(config)
+
+	t.Run("GetCurrentLoad", func(t *testing.T) {
+		metrics := monitor.GetCurrentLoad()
+		assert.NotNil(t, metrics)
+		assert.GreaterOrEqual(t, metrics.Score, 0.0)
+		assert.LessOrEqual(t, metrics.Score, 1.0)
+		assert.GreaterOrEqual(t, metrics.ActiveSessions, 0)
+	})
+
+	t.Run("SessionCount", func(t *testing.T) {
+		monitor.SetSessionCount(5)
+		assert.Equal(t, 5, monitor.GetSessionCount())
+
+		monitor.IncrementSessions()
+		assert.Equal(t, 6, monitor.GetSessionCount())
+
+		monitor.DecrementSessions()
+		assert.Equal(t, 5, monitor.GetSessionCount())
+	})
+
+	t.Run("GetAverageScore", func(t *testing.T) {
+		avg := monitor.GetAverageScore()
+		assert.GreaterOrEqual(t, avg, 0.0)
+		assert.LessOrEqual(t, avg, 1.0)
+	})
+}
+
+func TestEventDispatcher(t *testing.T) {
+	ed := NewEventDispatcher()
+
+	t.Run("SubscribeDispatch", func(t *testing.T) {
+		received := make(chan *NodeEvent, 1)
+
+		id := ed.Subscribe(func(event *NodeEvent) {
+			received <- event
+		})
+
+		event := &NodeEvent{
+			Node:  &NodeInfo{ID: "test-node"},
+			Event: EventJoin,
+			Time:  time.Now().UnixNano(),
+		}
+
+		ed.Dispatch(event)
+
+		select {
+		case <-received:
+			// Event received
+		case <-time.After(time.Second):
+			t.Fatal("Event not received")
+		}
+
+		ed.Unsubscribe(id)
+	})
+
+	t.Run("Unsubscribe", func(t *testing.T) {
+		received := make(chan *NodeEvent, 1)
+
+		id := ed.Subscribe(func(event *NodeEvent) {
+			received <- event
+		})
+
+		ed.Unsubscribe(id)
+
+		event := &NodeEvent{
+			Node:  &NodeInfo{ID: "test-node"},
+			Event: EventJoin,
+			Time:  time.Now().UnixNano(),
+		}
+
+		ed.Dispatch(event)
+
+		select {
+		case <-received:
+			t.Fatal("Should not receive event after unsubscribe")
+		case <-time.After(100 * time.Millisecond):
+			// Expected - no event received
+		}
+	})
+}
+
+func TestNodeWithState(t *testing.T) {
+	node := &NodeInfo{
+		ID:        "test-node",
+		Addr:      "192.168.1.1",
+		Port:      7947,
+		LoadScore: 0.5,
+		Timestamp: time.Now().UnixNano(),
+	}
+
+	nws := &NodeWithState{
+		Node: node,
+		State: &NodeState{
+			Status:      NodeStatusAlive,
+			StatusSince: time.Now().UnixNano(),
+			LastSeen:    time.Now().UnixNano(),
+		},
+	}
+
+	t.Run("IsAvailable", func(t *testing.T) {
+		assert.True(t, nws.IsAvailable())
+
+		// High load
+		nws.Node.LoadScore = 0.95
+		assert.False(t, nws.IsAvailable())
+
+		// Not alive
+		nws.Node.LoadScore = 0.5
+		nws.State.Status = NodeStatusDead
+		assert.False(t, nws.IsAvailable())
+	})
+}
+
+func TestDuration(t *testing.T) {
+	t.Run("UnmarshalJSON from string", func(t *testing.T) {
+		d := Duration{}
+		err := d.UnmarshalJSON([]byte(`"5s"`))
+		require.NoError(t, err)
+		assert.Equal(t, 5*time.Second, d.Duration)
+	})
+
+	t.Run("UnmarshalJSON from number (seconds)", func(t *testing.T) {
+		d := Duration{}
+		err := d.UnmarshalJSON([]byte(`10`))
+		require.NoError(t, err)
+		assert.Equal(t, 10*time.Second, d.Duration)
+	})
+
+	t.Run("UnmarshalJSON from fractional number", func(t *testing.T) {
+		d := Duration{}
+		err := d.UnmarshalJSON([]byte(`0.5`))
+		require.NoError(t, err)
+		assert.Equal(t, 500*time.Millisecond, d.Duration)
+	})
+
+	t.Run("MarshalJSON", func(t *testing.T) {
+		d := Duration{5 * time.Second}
+		data, err := d.MarshalJSON()
+		require.NoError(t, err)
+		assert.Equal(t, []byte(`"5s"`), data)
+	})
+}
+
+// Integration tests for NATS-based discovery, handoff, and leader election.
+// These tests require a running NATS server with JetStream enabled
+// and are skipped by default. Run with:
+//   NATS_URL=nats://localhost:4222 go test -run TestDiscovery -v
+
+func TestDiscoveryServiceNodeDiscovery(t *testing.T) {
+	t.Skip("Requires running NATS server with JetStream; set NATS_URL to enable")
+}
+
+func TestHandoffCoordinator(t *testing.T) {
+	t.Run("CanHandleWithLoadThreshold", func(t *testing.T) {
+		cfg := &Config{
+			NodeID: "handoff-node",
+			Handoff: HandoffConfig{
+				Enabled:       true,
+				LoadThreshold: 0.8,
+			},
+		}
+
+		ds, err := NewDiscoveryService(cfg)
+		require.NoError(t, err)
+
+		hc := NewHandoffCoordinator(ds, cfg.Handoff)
+		defer hc.Close()
+
+		// With low load, should be able to handle
+		ds.localNode.LoadScore = 0.5
+		assert.True(t, hc.CanHandle(""))
+
+		// With high load, should not be able to handle
+		ds.localNode.LoadScore = 0.9
+		assert.False(t, hc.CanHandle(""))
+	})
+
+	t.Run("FindTargetNode", func(t *testing.T) {
+		cfg := &Config{
+			NodeID: "coordinator-node",
+		}
+
+		ds, err := NewDiscoveryService(cfg)
+		require.NoError(t, err)
+
+		hc := NewHandoffCoordinator(ds, cfg.Handoff)
+		defer hc.Close()
+
+		// Add some candidate nodes
+		node1 := &NodeInfo{
+			ID:        "target-1",
+			Addr:      "192.168.1.1",
+			Port:      7947,
+			LoadScore: 0.3,
+			AgentCaps: map[string]string{"model": "gpt-4"},
+			Timestamp: time.Now().UnixNano(),
+		}
+		ds.membership.UpdateNode(node1)
+
+		node2 := &NodeInfo{
+			ID:        "target-2",
+			Addr:      "192.168.1.2",
+			Port:      7947,
+			LoadScore: 0.7,
+			AgentCaps: map[string]string{"model": "gpt-4"},
+			Timestamp: time.Now().UnixNano(),
+		}
+		ds.membership.UpdateNode(node2)
+
+		// Should select the least loaded node
+		target, err := hc.findTargetNode(&HandoffRequest{})
+		require.NoError(t, err)
+		assert.Equal(t, "target-1", target.Node.ID)
+	})
+}
+
+func TestLeaderElection(t *testing.T) {
+	t.Skip("Requires running NATS server with JetStream; set NATS_URL to enable")
+}

pkg/swarm/todo.go

@@ -0,0 +1,312 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+)
+
+// TodoItem represents a single todo item.
+type TodoItem struct {
+	ID          string    `json:"id"`
+	Title       string    `json:"title"`
+	Desc        string    `json:"description,omitempty"`
+	Priority    int       `json:"priority"` // 0=low, 1=medium, 2=high
+	Status      string    `json:"status"`   // "pending", "in_progress", "completed", "canceled"
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+	DueAt       time.Time `json:"due_at,omitempty"`
+	CompletedAt time.Time `json:"completed_at,omitempty"`
+	Tags        []string  `json:"tags,omitempty"`
+}
+
+// TodoList manages a list of todo items for a node.
+type TodoList struct {
+	items     []*TodoItem
+	mu        sync.RWMutex
+	nodeID    string
+	discovery *DiscoveryService // For publishing updates
+}
+
+// NewTodoList creates a new todo list for a node.
+func NewTodoList(nodeID string) *TodoList {
+	return &TodoList{
+		items:  make([]*TodoItem, 0),
+		nodeID: nodeID,
+	}
+}
+
+// SetDiscovery sets the discovery service for publishing updates.
+func (tl *TodoList) SetDiscovery(ds *DiscoveryService) {
+	tl.discovery = ds
+}
+
+// Add adds a new todo item.
+func (tl *TodoList) Add(title string, priority int) *TodoItem {
+	tl.mu.Lock()
+	defer tl.mu.Unlock()
+
+	now := time.Now()
+	item := &TodoItem{
+		ID:        generateTodoID(),
+		Title:     title,
+		Priority:  priority,
+		Status:    "pending",
+		CreatedAt: now,
+		UpdatedAt: now,
+	}
+
+	tl.items = append(tl.items, item)
+	tl.publishIfNeeded()
+	return item
+}
+
+// Update updates an existing todo item.
+func (tl *TodoList) Update(id string, updates func(*TodoItem)) bool {
+	tl.mu.Lock()
+	defer tl.mu.Unlock()
+
+	for _, item := range tl.items {
+		if item.ID == id {
+			updates(item)
+			item.UpdatedAt = time.Now()
+			tl.publishIfNeeded()
+			return true
+		}
+	}
+	return false
+}
+
+// Remove removes a todo item by ID.
+func (tl *TodoList) Remove(id string) bool {
+	tl.mu.Lock()
+	defer tl.mu.Unlock()
+
+	for i, item := range tl.items {
+		if item.ID == id {
+			tl.items = append(tl.items[:i], tl.items[i+1:]...)
+			tl.publishIfNeeded()
+			return true
+		}
+	}
+	return false
+}
+
+// Get retrieves a todo item by ID.
+func (tl *TodoList) Get(id string) *TodoItem {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	for _, item := range tl.items {
+		if item.ID == id {
+			return item
+		}
+	}
+	return nil
+}
+
+// List returns all todo items.
+func (tl *TodoList) List() []*TodoItem {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	result := make([]*TodoItem, len(tl.items))
+	copy(result, tl.items)
+	return result
+}
+
+// ListByStatus returns todo items filtered by status.
+func (tl *TodoList) ListByStatus(status string) []*TodoItem {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	result := make([]*TodoItem, 0)
+	for _, item := range tl.items {
+		if item.Status == status {
+			result = append(result, item)
+		}
+	}
+	return result
+}
+
+// ListByPriority returns todo items sorted by priority (highest first).
+func (tl *TodoList) ListByPriority() []*TodoItem {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	result := make([]*TodoItem, len(tl.items))
+	copy(result, tl.items)
+
+	// Simple bubble sort by priority (descending)
+	for i := 0; i < len(result)-1; i++ {
+		for j := 0; j < len(result)-i-1; j++ {
+			if result[j].Priority < result[j+1].Priority {
+				result[j], result[j+1] = result[j+1], result[j]
+			}
+		}
+	}
+	return result
+}
+
+// Complete marks a todo item as completed.
+func (tl *TodoList) Complete(id string) bool {
+	return tl.Update(id, func(item *TodoItem) {
+		item.Status = "completed"
+		item.CompletedAt = time.Now()
+	})
+}
+
+// Start marks a todo item as in progress.
+func (tl *TodoList) Start(id string) bool {
+	return tl.Update(id, func(item *TodoItem) {
+		item.Status = "in_progress"
+	})
+}
+
+// Cancel marks a todo item as canceled.
+func (tl *TodoList) Cancel(id string) bool {
+	return tl.Update(id, func(item *TodoItem) {
+		item.Status = "canceled"
+	})
+}
+
+// Clear removes all completed or canceled items.
+func (tl *TodoList) Clear() int {
+	tl.mu.Lock()
+	defer tl.mu.Unlock()
+
+	count := 0
+	newItems := make([]*TodoItem, 0, len(tl.items))
+	for _, item := range tl.items {
+		if item.Status != "completed" && item.Status != "canceled" {
+			newItems = append(newItems, item)
+		} else {
+			count++
+		}
+	}
+	tl.items = newItems
+
+	if count > 0 {
+		tl.publishIfNeeded()
+	}
+	return count
+}
+
+// Count returns the total number of todo items.
+func (tl *TodoList) Count() int {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+	return len(tl.items)
+}
+
+// CountByStatus returns the count of items by status.
+func (tl *TodoList) CountByStatus() map[string]int {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	counts := make(map[string]int)
+	for _, item := range tl.items {
+		counts[item.Status]++
+	}
+	return counts
+}
+
+// ToStrings converts the todo list to a slice of strings for status reporting.
+func (tl *TodoList) ToStrings() []string {
+	tl.mu.RLock()
+	defer tl.mu.RUnlock()
+
+	result := make([]string, 0, len(tl.items))
+	for _, item := range tl.items {
+		prefix := ""
+		switch item.Status {
+		case "completed":
+			prefix = "✅ "
+		case "in_progress":
+			prefix = "🔄 "
+		case "canceled":
+			prefix = "❌ "
+		case "pending":
+			if item.Priority == 2 {
+				prefix = "🔴 "
+			} else if item.Priority == 1 {
+				prefix = "🟡 "
+			} else {
+				prefix = "⚪ "
+			}
+		}
+		result = append(result, prefix+item.Title)
+	}
+	return result
+}
+
+// publishIfNeeded publishes the todo list to the discovery service if available.
+func (tl *TodoList) publishIfNeeded() {
+	if tl.discovery == nil {
+		return
+	}
+
+	todoStrings := tl.ToStrings()
+	tl.discovery.SetTodoList(todoStrings)
+}
+
+// generateTodoID generates a unique ID for a todo item.
+func generateTodoID() string {
+	return time.Now().Format("20060102-150405") + "-" + randomString(4)
+}
+
+// randomString generates a random string of given length.
+func randomString(n int) string {
+	const letters = "abcdefghijklmnopqrstuvwxyz0123456789"
+	b := make([]byte, n)
+	for i := range b {
+		b[i] = letters[time.Now().UnixNano()%int64(len(letters))]
+		time.Sleep(time.Nanosecond)
+	}
+	return string(b)
+}
+
+// TodoListSummary represents a summary of a node's todo list.
+type TodoListSummary struct {
+	NodeID       string `json:"node_id"`
+	Total        int    `json:"total"`
+	Pending      int    `json:"pending"`
+	InProgress   int    `json:"in_progress"`
+	Completed    int    `json:"completed"`
+	Canceled     int    `json:"canceled"`
+	HighPriority int    `json:"high_priority"`
+	Timestamp    int64  `json:"timestamp"`
+}
+
+// Summary returns a summary of the todo list.
+func (tl *TodoList) Summary() *TodoListSummary {
+	counts := tl.CountByStatus()
+	highPriority := 0
+	for _, item := range tl.items {
+		if item.Priority == 2 && item.Status != "completed" && item.Status != "canceled" {
+			highPriority++
+		}
+	}
+
+	return &TodoListSummary{
+		NodeID:       tl.nodeID,
+		Total:        tl.Count(),
+		Pending:      counts["pending"],
+		InProgress:   counts["in_progress"],
+		Completed:    counts["completed"],
+		Canceled:     counts["canceled"],
+		HighPriority: highPriority,
+		Timestamp:    time.Now().UnixNano(),
+	}
+}
+
+// MarshalJSON implements json.Marshaler.
+func (tl *TodoList) MarshalJSON() ([]byte, error) {
+	return json.Marshal(tl.List())
+}

pkg/swarm/view.go

@@ -0,0 +1,100 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package swarm
+
+import "time"
+
+// View represents a snapshot of the cluster state.
+// It is an immutable snapshot that can be safely passed between components.
+type View struct {
+	Nodes       []*NodeInfo `json:"nodes"`
+	LocalNodeID string      `json:"local_node_id"`
+	Version     int64       `json:"version"`   // View version for change detection
+	Timestamp   int64       `json:"timestamp"` // When this view was captured (Unix nano)
+}
+
+// NodeInfoInContext extends NodeInfo with runtime state from the view.
+type NodeInfoInContext struct {
+	Node      *NodeInfo
+	IsAlive   bool
+	IsLocal   bool
+	LastSeen  time.Time
+	LoadScore float64
+}
+
+// Get returns node info by ID from the view.
+func (v *View) Get(nodeID string) *NodeInfoInContext {
+	for _, n := range v.Nodes {
+		if n.ID == nodeID {
+			return &NodeInfoInContext{
+				Node:      n,
+				IsAlive:   n.Status == "alive" || n.Status == "",
+				IsLocal:   n.ID == v.LocalNodeID,
+				LastSeen:  n.GetLastSeen(),
+				LoadScore: n.LoadScore,
+			}
+		}
+	}
+	return nil
+}
+
+// AliveNodes returns all alive nodes excluding the local node.
+func (v *View) AliveNodes() []*NodeInfo {
+	result := make([]*NodeInfo, 0)
+	for _, n := range v.Nodes {
+		if n.ID != v.LocalNodeID && (n.Status == "alive" || n.Status == "") {
+			result = append(result, n)
+		}
+	}
+	return result
+}
+
+// AvailableNodes returns all alive nodes with available capacity.
+func (v *View) AvailableNodes(loadThreshold float64) []*NodeInfo {
+	result := make([]*NodeInfo, 0)
+	for _, n := range v.Nodes {
+		if n.ID != v.LocalNodeID && (n.Status == "alive" || n.Status == "") {
+			if n.LoadScore < loadThreshold {
+				result = append(result, n)
+			}
+		}
+	}
+	return result
+}
+
+// NodeCount returns the total number of nodes in the view.
+func (v *View) NodeCount() int {
+	return len(v.Nodes)
+}
+
+// AliveCount returns the number of alive nodes in the view.
+func (v *View) AliveCount() int {
+	count := 0
+	for _, n := range v.Nodes {
+		if n.Status == "alive" || n.Status == "" {
+			count++
+		}
+	}
+	return count
+}
+
+// HasNode returns true if the view contains the given node ID.
+func (v *View) HasNode(nodeID string) bool {
+	for _, n := range v.Nodes {
+		if n.ID == nodeID {
+			return true
+		}
+	}
+	return false
+}
+
+// NodeChange represents a change in the cluster view.
+type NodeChange struct {
+	Node    *NodeInfo
+	Join    bool // true if node joined, false if left/updated
+	Updated bool // true if node was updated (status changed, etc.)
+}

pkg/tools/handoff_tool.go

@@ -0,0 +1,140 @@
+// PicoClaw - Ultra-lightweight personal AI agent
+// Swarm mode support for multi-agent coordination
+// License: MIT
+//
+// Copyright (c) 2026 PicoClaw contributors
+
+package tools
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/sipeed/picoclaw/pkg/swarm"
+)
+
+// HandoffTool implements the handoff tool for swarm mode.
+type HandoffTool struct {
+	coordinator *swarm.HandoffCoordinator
+	channel     string
+	chatID      string
+}
+
+// NewHandoffTool creates a new handoff tool.
+func NewHandoffTool(coordinator *swarm.HandoffCoordinator) *HandoffTool {
+	return &HandoffTool{
+		coordinator: coordinator,
+		channel:     "cli",
+		chatID:      "direct",
+	}
+}
+
+// Name returns the tool name.
+func (t *HandoffTool) Name() string {
+	return "handoff"
+}
+
+// Description returns the tool description.
+func (t *HandoffTool) Description() string {
+	return "Delegate this task to another agent in the swarm. Use when you cannot handle the task due to capability constraints or system overload."
+}
+
+// Parameters returns the tool parameters schema.
+func (t *HandoffTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"reason": map[string]any{
+				"type":        "string",
+				"enum":        []string{"no_capability", "overloaded", "user_request"},
+				"description": "The reason for handing off this task",
+			},
+			"required_capability": map[string]any{
+				"type":        "string",
+				"description": "The specific capability required to handle this task",
+			},
+			"context": map[string]any{
+				"type":        "string",
+				"description": "Additional context about why this handoff is needed",
+			},
+		},
+	}
+}
+
+// SetContext sets the channel and chat ID for the tool.
+func (t *HandoffTool) SetContext(channel, chatID string) {
+	t.channel = channel
+	t.chatID = chatID
+}
+
+// Execute executes the handoff tool.
+func (t *HandoffTool) Execute(ctx context.Context, args map[string]any) *ToolResult {
+	if t.coordinator == nil {
+		return ErrorResult("Swarm mode is not enabled or handoff coordinator not configured").WithError(
+			fmt.Errorf("handoff coordinator is nil"))
+	}
+
+	// Parse reason
+	reasonStr, _ := args["reason"].(string)
+	var reason swarm.HandoffReason
+	switch reasonStr {
+	case "no_capability":
+		reason = swarm.ReasonNoCapability
+	case "overloaded":
+		reason = swarm.ReasonOverloaded
+	case "user_request":
+		reason = swarm.ReasonUserRequest
+	default:
+		reason = swarm.ReasonNoCapability
+	}
+
+	// Parse required capability
+	requiredCap, _ := args["required_capability"].(string)
+
+	// Parse context
+	contextMsg, _ := args["context"].(string)
+
+	// Build handoff request
+	req := &swarm.HandoffRequest{
+		Reason:      reason,
+		RequiredCap: requiredCap,
+		Metadata:    make(map[string]string),
+	}
+
+	if contextMsg != "" {
+		req.Metadata["context"] = contextMsg
+	}
+
+	// Execute handoff
+	resp, err := t.coordinator.InitiateHandoff(ctx, req)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("Handoff failed: %v", err)).WithError(err)
+	}
+
+	if !resp.Accepted {
+		return ErrorResult(fmt.Sprintf("Handoff rejected by all nodes: %s", resp.Reason)).WithError(
+			fmt.Errorf("handoff rejected: %s", resp.Reason))
+	}
+
+	// Build result message
+	resultMsg := fmt.Sprintf("Task handed off to node %s\n", resp.NodeID)
+	if resp.Reason != "" {
+		resultMsg += fmt.Sprintf("Note: %s\n", resp.Reason)
+	}
+
+	return &ToolResult{
+		ForLLM:  resultMsg + "The target node will process this task and respond to the user.",
+		ForUser: "Your task has been delegated to another agent in the swarm. They will respond shortly.",
+		Silent:  false,
+		IsError: false,
+		Async:   true, // Handoff is async - target node will respond directly
+	}
+}
+
+// CanHandle reports whether the local node can handle the given capability.
+func (t *HandoffTool) CanHandle(requiredCap string) bool {
+	if t.coordinator == nil {
+		return true // If swarm is disabled, we can "handle" everything
+	}
+	return t.coordinator.CanHandle(requiredCap)
+}

pkg/tools/swarm_batch.go

@@ -0,0 +1,267 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/sipeed/picoclaw/pkg/swarm"
+)
+
+// SwarmBatchTool queries multiple nodes in parallel.
+type SwarmBatchTool struct {
+	discovery    swarm.Discovery
+	localID      string
+	sendActionFn func(ctx context.Context, targetNodeID, action string) (string, error)
+}
+
+// NewSwarmBatchTool creates a new swarm batch query tool.
+func NewSwarmBatchTool(
+	discovery swarm.Discovery,
+	localID string,
+) *SwarmBatchTool {
+	return &SwarmBatchTool{
+		discovery: discovery,
+		localID:   localID,
+	}
+}
+
+// SetSendActionFn sets the function to send actions to other nodes.
+func (t *SwarmBatchTool) SetSendActionFn(
+	fn func(ctx context.Context, targetNodeID, action string) (string, error),
+) {
+	t.sendActionFn = fn
+}
+
+// Name returns the tool name.
+func (t *SwarmBatchTool) Name() string {
+	return "swarm_batch"
+}
+
+// Description returns the tool description.
+func (t *SwarmBatchTool) Description() string {
+	//nolint:gosmopolitan // Intentional Chinese examples for bilingual LLM tool descriptions
+	return "Broadcast query to ALL nodes in parallel (fast, <10ms). " +
+		"IMPORTANT: Use this FIRST when asking about multiple nodes (e.g., '所有节点状态', 'node-01和node-02的状态'). " +
+		"DO NOT use swarm_route for each node - use this ONCE to get all data. " +
+		"For single node specific tasks, use swarm_route with action='message'."
+}
+
+// Parameters returns the tool parameters schema.
+func (t *SwarmBatchTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"node_ids": map[string]any{
+				"type":        "array",
+				"items":       map[string]any{"type": "string"},
+				"description": "List of node IDs to query (optional, defaults to all nodes)",
+			},
+			"action": map[string]any{
+				"type":        "string",
+				"enum":        []string{"status", "message"},
+				"default":     "status",
+				"description": "Action type: 'status' (default, fast) returns structured data; 'message' requires a message parameter",
+			},
+			"message": map[string]any{
+				"type":        "string",
+				"description": "Message to send (only for action='message')",
+			},
+			"verbose": map[string]any{
+				"type":        "boolean",
+				"description": "Include detailed information",
+			},
+		},
+	}
+}
+
+// Execute executes the batch query in parallel.
+func (t *SwarmBatchTool) Execute(ctx context.Context, args map[string]any) *ToolResult {
+	if t.discovery == nil {
+		return ErrorResult("Swarm mode is not enabled")
+	}
+
+	action, _ := args["action"].(string)
+	if action == "" {
+		action = "status"
+	}
+	message, _ := args["message"].(string)
+	verbose := false
+	if v, ok := args["verbose"].(bool); ok {
+		verbose = v
+	}
+
+	// Get target nodes
+	var targetIDs []string
+	if nodeIDsRaw, ok := args["node_ids"].([]any); ok {
+		for _, id := range nodeIDsRaw {
+			if idStr, ok := id.(string); ok {
+				targetIDs = append(targetIDs, idStr)
+			}
+		}
+	}
+
+	// If no nodes specified, query all nodes except local
+	if len(targetIDs) == 0 {
+		members := t.discovery.Members()
+		for _, m := range members {
+			if m.Node.ID != t.localID {
+				targetIDs = append(targetIDs, m.Node.ID)
+			}
+		}
+	}
+
+	if len(targetIDs) == 0 {
+		return ErrorResult("No nodes to query")
+	}
+
+	// For status action with detailed status available, use fast path
+	if action == "status" {
+		if provider, ok := t.discovery.(swarm.DetailedStatusProvider); ok {
+			if statusRegistry := provider.GetDetailedStatus(); statusRegistry != nil {
+				return t.executeFastStatusQuery(statusRegistry, targetIDs, verbose)
+			}
+		}
+	}
+
+	// Otherwise, use parallel action queries
+	return t.executeParallelQueries(ctx, targetIDs, action, message)
+}
+
+// executeFastStatusQuery queries all nodes from local status cache (fastest).
+func (t *SwarmBatchTool) executeFastStatusQuery(
+	statusRegistry *swarm.NodeDetailedStatus,
+	nodeIDs []string,
+	verbose bool,
+) *ToolResult {
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("📊 Batch Status Query (%d nodes):\n\n", len(nodeIDs)))
+
+	for _, nodeID := range nodeIDs {
+		status, ok := statusRegistry.Get(nodeID)
+		if !ok {
+			sb.WriteString(fmt.Sprintf("**%s**: ❌ No status data available\n", nodeID))
+			continue
+		}
+
+		sb.WriteString(fmt.Sprintf("**%s**", nodeID))
+
+		// Format uptime
+		uptime := fmt.Sprintf("%.1fm", float64(status.Uptime)/60)
+		sb.WriteString(fmt.Sprintf(" (up: %s)", uptime))
+
+		if verbose {
+			sb.WriteString(fmt.Sprintf("\n   Address: %s:%d\n", status.Addr, status.HTTPPort))
+			sb.WriteString(fmt.Sprintf("   Load: %.1f%% | CPU: %.1f%% | Mem: %.1f%% (%.1f MB)\n",
+				status.LoadScore*100, status.CPUUsage*100, status.MemoryUsage*100,
+				float64(status.MemoryBytes)/(1024*1024)))
+			sb.WriteString(fmt.Sprintf("   Sessions: %d | Goroutines: %d\n",
+				status.ActiveSessions, status.Goroutines))
+
+			if len(status.TodoList) > 0 {
+				sb.WriteString("   Todo:\n")
+				for i, todo := range status.TodoList {
+					if i >= 3 {
+						sb.WriteString(fmt.Sprintf("     ... and %d more\n", len(status.TodoList)-3))
+						break
+					}
+					sb.WriteString(fmt.Sprintf("     - %s\n", todo))
+				}
+			}
+
+			if status.ActiveTasks > 0 {
+				sb.WriteString(fmt.Sprintf("   Active Tasks: %d\n", status.ActiveTasks))
+			}
+		} else {
+			sb.WriteString(fmt.Sprintf(" — Load: %.0f%% | Mem: %.0f%%",
+				status.LoadScore*100, status.MemoryUsage*100))
+
+			if len(status.TodoList) > 0 {
+				sb.WriteString(fmt.Sprintf(" | Todo: %d", len(status.TodoList)))
+			}
+			sb.WriteString("\n")
+		}
+		sb.WriteString("\n")
+	}
+
+	return &ToolResult{
+		ForLLM:  sb.String(),
+		ForUser: sb.String(),
+		IsError: false,
+	}
+}
+
+// executeParallelQueries sends parallel requests to all nodes.
+func (t *SwarmBatchTool) executeParallelQueries(
+	ctx context.Context,
+	nodeIDs []string,
+	action, message string,
+) *ToolResult {
+	if t.sendActionFn == nil {
+		return ErrorResult("Inter-node communication not available")
+	}
+
+	var wg sync.WaitGroup
+	results := make(map[string]string)
+	errors := make(map[string]string)
+	var mu sync.Mutex
+
+	members := t.discovery.Members()
+	nodeMap := make(map[string]*swarm.NodeWithState)
+	for _, m := range members {
+		nodeMap[m.Node.ID] = m
+	}
+
+	for _, nodeID := range nodeIDs {
+		wg.Add(1)
+		go func(nid string) {
+			defer wg.Done()
+
+			target := nodeMap[nid]
+			if target == nil {
+				mu.Lock()
+				errors[nid] = "Node not found"
+				mu.Unlock()
+				return
+			}
+
+			if target.State.Status != swarm.NodeStatusAlive {
+				mu.Lock()
+				errors[nid] = fmt.Sprintf("Node not alive (status: %s)", target.State.Status)
+				mu.Unlock()
+				return
+			}
+
+			result, err := t.sendActionFn(ctx, nid, action)
+			mu.Lock()
+			defer mu.Unlock()
+			if err != nil {
+				errors[nid] = err.Error()
+			} else {
+				results[nid] = result
+			}
+		}(nodeID)
+	}
+
+	wg.Wait()
+
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("📊 Batch Query Results (%d nodes):\n\n", len(nodeIDs)))
+
+	for _, nodeID := range nodeIDs {
+		sb.WriteString(fmt.Sprintf("**%s**:\n", nodeID))
+		if result, ok := results[nodeID]; ok {
+			sb.WriteString(result)
+		} else if err, ok := errors[nodeID]; ok {
+			sb.WriteString(fmt.Sprintf("❌ Error: %s\n", err))
+		}
+		sb.WriteString("\n")
+	}
+
+	return &ToolResult{
+		ForLLM:  sb.String(),
+		ForUser: sb.String(),
+		IsError: len(errors) == 0,
+	}
+}

pkg/tools/swarm_nodes.go

@@ -0,0 +1,748 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/logger"
+	"github.com/sipeed/picoclaw/pkg/swarm"
+)
+
+// FormatClusterStatus returns a human-readable cluster status string.
+// Used by the /nodes command handler.
+// Now uses detailed status from NATS KV for fast queries without sending requests to other nodes.
+func FormatClusterStatus(
+	discovery swarm.Discovery,
+	load *swarm.LoadMonitor,
+	localID string,
+	verbose bool,
+) string {
+	if discovery == nil {
+		return "Swarm mode is not enabled."
+	}
+
+	members := discovery.Members()
+	if len(members) == 0 {
+		return "No nodes found in the swarm cluster."
+	}
+
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("Swarm Cluster Status (%d node%s):\n\n", len(members), plural(len(members))))
+
+	// Sort nodes: local first, then by ID
+	sortedMembers := make([]*swarm.NodeWithState, len(members))
+	copy(sortedMembers, members)
+	sort.Slice(sortedMembers, func(i, j int) bool {
+		// Local node always comes first
+		if sortedMembers[i].Node.ID == localID {
+			return true
+		}
+		if sortedMembers[j].Node.ID == localID {
+			return false
+		}
+		return sortedMembers[i].Node.ID < sortedMembers[j].Node.ID
+	})
+
+	// Try to get detailed status from discovery (if it supports it)
+	var detailedStatuses map[string]*swarm.NodeDetailedInfo
+	if provider, ok := discovery.(swarm.DetailedStatusProvider); ok {
+		statusRegistry := provider.GetDetailedStatus()
+		if statusRegistry != nil {
+			detailedStatuses = make(map[string]*swarm.NodeDetailedInfo)
+			for _, status := range statusRegistry.GetAll() {
+				detailedStatuses[status.ID] = status
+			}
+		}
+	}
+
+	for _, m := range sortedMembers {
+		node := m.Node
+		state := m.State
+
+		localMark := " "
+		if node.ID == localID {
+			localMark = "*"
+		}
+
+		sb.WriteString(fmt.Sprintf("%s **%s**", localMark, node.ID))
+
+		// Check if we have detailed status from KV
+		detailed := detailedStatuses[node.ID]
+		if detailed != nil {
+			// Use detailed status from KV (fast path)
+			sb.WriteString(formatDetailedNodeStatus(detailed, verbose))
+		} else {
+			// Fallback to basic status
+			sb.WriteString(formatBasicNodeStatus(node, state, verbose))
+		}
+
+		sb.WriteString("\n")
+	}
+
+	sb.WriteString("* = this node\n")
+	sb.WriteString("\nTip: Use `@node-id: message` to route a request to a specific node.")
+
+	return sb.String()
+}
+
+// formatDetailedNodeStatus formats node status from detailed info (from KV).
+func formatDetailedNodeStatus(node *swarm.NodeDetailedInfo, verbose bool) string {
+	var result strings.Builder
+
+	// Add uptime
+	uptime := time.Duration(node.Uptime) * time.Second
+	result.WriteString(fmt.Sprintf(" (uptime: %s)", formatDuration(uptime)))
+
+	if node.Status != "" {
+		result.WriteString(fmt.Sprintf(" [%s]", node.Status))
+	}
+	result.WriteString("\n")
+
+	if verbose {
+		result.WriteString(fmt.Sprintf("   Address: %s:%d (HTTP: %d)\n", node.Addr, node.Port, node.HTTPPort))
+
+		// Load metrics with emoji
+		result.WriteString(fmt.Sprintf("   Load: %.1f%%", node.LoadScore*100))
+		if node.LoadScore < 0.5 {
+			result.WriteString(" 🟩")
+		} else if node.LoadScore < 0.8 {
+			result.WriteString(" 🟨")
+		} else {
+			result.WriteString(" 🟥")
+		}
+		result.WriteString(fmt.Sprintf(" | CPU: %.1f%% | Mem: %.1f%% (%.1f MB)\n",
+			node.CPUUsage*100, node.MemoryUsage*100, float64(node.MemoryBytes)/(1024*1024)))
+
+		// Active sessions and goroutines
+		result.WriteString(fmt.Sprintf("   Sessions: %d | Goroutines: %d\n", node.ActiveSessions, node.Goroutines))
+
+		// Todo list
+		if len(node.TodoList) > 0 {
+			result.WriteString("   Todo:\n")
+			for i, todo := range node.TodoList {
+				if i >= 5 { // Limit to 5 items
+					result.WriteString(fmt.Sprintf("     ... and %d more\n", len(node.TodoList)-5))
+					break
+				}
+				result.WriteString(fmt.Sprintf("     - %s\n", todo))
+			}
+		}
+
+		// Active tasks
+		if node.ActiveTasks > 0 {
+			result.WriteString(fmt.Sprintf("   Active Tasks: %d\n", node.ActiveTasks))
+		}
+
+		// Disk usage
+		if node.DiskUsagePercent > 0 {
+			result.WriteString(fmt.Sprintf("   Disk: %.1f%% used", node.DiskUsagePercent))
+			if node.DiskUsedBytes > 0 && node.DiskTotalBytes > 0 {
+				result.WriteString(fmt.Sprintf(" (%.1f GB / %.1f GB)",
+					float64(node.DiskUsedBytes)/(1024*1024*1024),
+					float64(node.DiskTotalBytes)/(1024*1024*1024)))
+			}
+			result.WriteString("\n")
+		}
+
+		// Last error
+		if node.LastError != "" {
+			result.WriteString(fmt.Sprintf("   Last Error: %s\n", node.LastError))
+		}
+
+		// Version info
+		if node.Version != "" {
+			result.WriteString(fmt.Sprintf("   Version: %s (%s/%s)\n", node.Version, node.OS, node.Arch))
+		}
+	} else {
+		// Compact format
+		result.WriteString(fmt.Sprintf(" — Load: %.0f%% | Mem: %.0f%%",
+			node.LoadScore*100, node.MemoryUsage*100))
+
+		if len(node.TodoList) > 0 {
+			result.WriteString(fmt.Sprintf(" | Todo: %d", len(node.TodoList)))
+		}
+
+		if node.ActiveTasks > 0 {
+			result.WriteString(fmt.Sprintf(" | Tasks: %d", node.ActiveTasks))
+		}
+
+		result.WriteString("\n")
+	}
+
+	return result.String()
+}
+
+// formatBasicNodeStatus formats node status from basic info (fallback).
+func formatBasicNodeStatus(node *swarm.NodeInfo, state *swarm.NodeState, verbose bool) string {
+	var result strings.Builder
+
+	if state != nil {
+		writeStatusIndicator(&result, state.Status)
+		result.WriteString(fmt.Sprintf(" Load: %.0f%%", node.LoadScore*100))
+	}
+
+	result.WriteString(fmt.Sprintf(" @ %s:%d\n", node.Addr, node.Port))
+
+	if verbose && state != nil {
+		result.WriteString(fmt.Sprintf("   Status: %s\n", state.Status))
+
+		loadPercent := int(node.LoadScore * 100)
+		result.WriteString(fmt.Sprintf("   Load: %.2f%% ", node.LoadScore*100))
+		if loadPercent < 50 {
+			result.WriteString("🟩")
+		} else if loadPercent < 80 {
+			result.WriteString("🟨")
+		} else {
+			result.WriteString("🟥")
+		}
+		result.WriteString("\n")
+
+		lastSeen := time.Unix(0, state.LastSeen)
+		age := time.Since(lastSeen)
+		result.WriteString(fmt.Sprintf("   Last seen: %s ago\n", formatDuration(age)))
+
+		if len(node.AgentCaps) > 0 {
+			result.WriteString("   Capabilities:\n")
+			for k, v := range node.AgentCaps {
+				result.WriteString(fmt.Sprintf("     - %s: %s\n", k, v))
+			}
+		}
+
+		if len(node.Labels) > 0 {
+			result.WriteString("   Labels:\n")
+			for k, v := range node.Labels {
+				result.WriteString(fmt.Sprintf("     - %s: %s\n", k, v))
+			}
+		}
+	}
+
+	return result.String()
+}
+
+// writeStatusIndicator writes a status indicator to the builder.
+func writeStatusIndicator(sb *strings.Builder, status swarm.NodeStatus) {
+	switch status {
+	case swarm.NodeStatusAlive:
+		sb.WriteString(" 🟢")
+	case swarm.NodeStatusSuspect:
+		sb.WriteString(" 🟡")
+	case swarm.NodeStatusDead:
+		sb.WriteString(" 🔴")
+	case swarm.NodeStatusLeft:
+		sb.WriteString(" ⚪")
+	}
+}
+
+// SwarmNodesTool returns current swarm cluster node status.
+type SwarmNodesTool struct {
+	discovery swarm.Discovery
+	load      *swarm.LoadMonitor
+	localID   string
+}
+
+// NewSwarmNodesTool creates a new swarm nodes status tool.
+func NewSwarmNodesTool(
+	discovery swarm.Discovery,
+	load *swarm.LoadMonitor,
+	localID string,
+) *SwarmNodesTool {
+	return &SwarmNodesTool{
+		discovery: discovery,
+		load:      load,
+		localID:   localID,
+	}
+}
+
+// Name returns the tool name.
+func (t *SwarmNodesTool) Name() string {
+	return "swarm_nodes"
+}
+
+// Description returns the tool description.
+func (t *SwarmNodesTool) Description() string {
+	//nolint:gosmopolitan // Intentional Chinese examples for bilingual LLM tool descriptions
+	return "List ALL swarm cluster nodes and their detailed status in ONE call (fast, parallel, reads from local cache). " +
+		"IMPORTANT: This already returns status for ALL nodes - do NOT call swarm_route for each node individually. " +
+		"Use for questions like '查看所有节点状态', 'cluster status', '节点列表', etc."
+}
+
+// Parameters returns the tool parameters schema.
+func (t *SwarmNodesTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"verbose": map[string]any{
+				"type":        "boolean",
+				"description": "Whether to include detailed status for each node",
+			},
+		},
+	}
+}
+
+// Execute executes the swarm nodes tool.
+func (t *SwarmNodesTool) Execute(_ context.Context, args map[string]any) *ToolResult {
+	if t.discovery == nil {
+		return ErrorResult("Swarm mode is not enabled")
+	}
+
+	verbose := false
+	if rawVerbose, ok := args["verbose"]; ok {
+		switch v := rawVerbose.(type) {
+		case bool:
+			verbose = v
+		case string:
+			lower := strings.ToLower(strings.TrimSpace(v))
+			verbose = lower == "true" || lower == "1" || lower == "yes" || lower == "y"
+		}
+	}
+
+	status := FormatClusterStatus(t.discovery, t.load, t.localID, verbose)
+	return &ToolResult{
+		ForLLM:  status,
+		ForUser: status,
+		IsError: false,
+	}
+}
+
+// SwarmTool provides a generalized swarm entrypoint for status/query and routing.
+type SwarmTool struct {
+	discovery     swarm.Discovery
+	load          *swarm.LoadMonitor
+	localID       string
+	sendMessageFn func(ctx context.Context, targetNodeID, content, channel, chatID, senderID string) (string, error)
+}
+
+// NewSwarmTool creates a new generalized swarm tool.
+func NewSwarmTool(
+	discovery swarm.Discovery,
+	load *swarm.LoadMonitor,
+	localID string,
+) *SwarmTool {
+	return &SwarmTool{
+		discovery: discovery,
+		load:      load,
+		localID:   localID,
+	}
+}
+
+// SetSendMessageFn sets the function used to send messages to other nodes.
+func (t *SwarmTool) SetSendMessageFn(
+	fn func(ctx context.Context, targetNodeID, content, channel, chatID, senderID string) (string, error),
+) {
+	t.sendMessageFn = fn
+}
+
+// Name returns the tool name.
+func (t *SwarmTool) Name() string {
+	return "swarm_tool"
+}
+
+// Description returns the tool description.
+func (t *SwarmTool) Description() string {
+	return "General swarm tool: list swarm nodes/status and route a message to a specific node."
+}
+
+// Parameters returns the tool parameters schema.
+func (t *SwarmTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"action": map[string]any{
+				"type":        "string",
+				"enum":        []string{"list_nodes", "route_message"},
+				"description": "Operation type: list_nodes to query node status, route_message to send to another node",
+			},
+			"verbose": map[string]any{
+				"type":        "boolean",
+				"description": "When action is list_nodes, include detailed fields",
+			},
+			"node_id": map[string]any{
+				"type":        "string",
+				"description": "When action is route_message, target node ID",
+			},
+			"message": map[string]any{
+				"type":        "string",
+				"description": "When action is route_message, message content to send",
+			},
+			"channel": map[string]any{
+				"type":        "string",
+				"description": "Source channel identifier for routing context (optional, auto-filled from context when available)",
+			},
+			"chat_id": map[string]any{
+				"type":        "string",
+				"description": "Source chat/conversation ID for continuity (optional, auto-filled from context when available)",
+			},
+			"sender_id": map[string]any{
+				"type":        "string",
+				"description": "Sender identity for audit and reply routing (optional, auto-filled from context when available)",
+			},
+			"trace_id": map[string]any{
+				"type":        "string",
+				"description": "Distributed trace ID for cross-node observability (optional)",
+			},
+		},
+		"required": []string{"action"},
+		"oneOf": []any{
+			map[string]any{
+				"properties": map[string]any{
+					"action": map[string]any{"const": "list_nodes"},
+				},
+			},
+			map[string]any{
+				"properties": map[string]any{
+					"action": map[string]any{"const": "route_message"},
+				},
+				"required": []string{"node_id", "message"},
+			},
+		},
+	}
+}
+
+// Execute executes the generalized swarm tool.
+func (t *SwarmTool) Execute(ctx context.Context, args map[string]any) *ToolResult {
+	if t.discovery == nil {
+		return ErrorResult("Swarm mode is not enabled")
+	}
+
+	action, _ := args["action"].(string)
+	action = strings.ToLower(strings.TrimSpace(action))
+
+	// Fallback inference when model omits action.
+	if action == "" {
+		if nodeID, _ := args["node_id"].(string); strings.TrimSpace(nodeID) != "" {
+			action = "route_message"
+		} else {
+			action = "list_nodes"
+		}
+	}
+
+	switch action {
+	case "list_nodes":
+		verbose := false
+		if rawVerbose, ok := args["verbose"]; ok {
+			switch v := rawVerbose.(type) {
+			case bool:
+				verbose = v
+			case string:
+				lower := strings.ToLower(strings.TrimSpace(v))
+				verbose = lower == "true" || lower == "1" || lower == "yes" || lower == "y"
+			}
+		}
+		status := FormatClusterStatus(t.discovery, t.load, t.localID, verbose)
+		return &ToolResult{
+			ForLLM:  status,
+			ForUser: status,
+			IsError: false,
+		}
+
+	case "route_message":
+		nodeID, _ := args["node_id"].(string)
+		nodeID = strings.TrimSpace(nodeID)
+		message, _ := args["message"].(string)
+
+		if nodeID == "" {
+			return ErrorResult("node_id is required when action=route_message")
+		}
+		if message == "" {
+			return ErrorResult("message is required when action=route_message")
+		}
+		if nodeID == t.localID {
+			return &ToolResult{
+				ForLLM: fmt.Sprintf(
+					"Target node %s is this node. Process locally instead of routing.",
+					nodeID,
+				),
+				//nolint:gosmopolitan // Intentional Chinese user-facing message
+				ForUser: fmt.Sprintf("目标节点 %s 就是当前节点，已建议本地处理。", nodeID),
+				IsError: false,
+			}
+		}
+		if t.sendMessageFn == nil {
+			return ErrorResult("inter-node messaging is not available")
+		}
+
+		// Extract optional context parameters for cross-node traceability.
+		channel, _ := args["channel"].(string)
+		chatID, _ := args["chat_id"].(string)
+		senderID, _ := args["sender_id"].(string)
+
+		response, err := t.sendMessageFn(ctx, nodeID, message, channel, chatID, senderID)
+		if err != nil {
+			return ErrorResult(fmt.Sprintf("failed to send message to node %s: %v", nodeID, err))
+		}
+		return &ToolResult{
+			ForLLM:  response,
+			ForUser: response,
+			IsError: false,
+		}
+	default:
+		return ErrorResult("invalid action, supported: list_nodes, route_message")
+	}
+}
+
+// SwarmRouteTool routes a request to a specific node in the swarm.
+type SwarmRouteTool struct {
+	discovery     swarm.Discovery
+	handoff       *swarm.HandoffCoordinator
+	localID       string
+	sendMessageFn func(ctx context.Context, targetNodeID, content, channel, chatID, senderID string) (string, error)
+	sendActionFn  func(ctx context.Context, targetNodeID, action string) (string, error)
+}
+
+// NewSwarmRouteTool creates a new swarm route tool.
+func NewSwarmRouteTool(
+	discovery swarm.Discovery,
+	handoff *swarm.HandoffCoordinator,
+	localID string,
+) *SwarmRouteTool {
+	return &SwarmRouteTool{
+		discovery: discovery,
+		handoff:   handoff,
+		localID:   localID,
+	}
+}
+
+// SetSendMessageFn sets the function to send messages to other nodes.
+func (t *SwarmRouteTool) SetSendMessageFn(
+	fn func(ctx context.Context, targetNodeID, content, channel, chatID, senderID string) (string, error),
+) {
+	t.sendMessageFn = fn
+}
+
+// SetSendActionFn sets the function to send actions to other nodes.
+func (t *SwarmRouteTool) SetSendActionFn(
+	fn func(ctx context.Context, targetNodeID, action string) (string, error),
+) {
+	t.sendActionFn = fn
+}
+
+// Name returns the tool name.
+func (t *SwarmRouteTool) Name() string {
+	return "swarm_route"
+}
+
+// Description returns the tool description.
+func (t *SwarmRouteTool) Description() string {
+	return "Send a request to a SINGLE node. " +
+		"WARNING: Use swarm_batch or swarm_nodes FIRST for multi-node queries - they are MUCH FASTER. " +
+		"Only use this when you need ONE specific node to perform a task. " +
+		"For status, use action='status' (<10ms); for LLM tasks, use action='message' with a message."
+}
+
+// Parameters returns the tool parameters schema.
+func (t *SwarmRouteTool) Parameters() map[string]any {
+	return map[string]any{
+		"type": "object",
+		"properties": map[string]any{
+			"node_id": map[string]any{
+				"type":        "string",
+				"description": "The target node ID to route the request to",
+			},
+			"action": map[string]any{
+				"type":        "string",
+				"enum":        []string{"status", "message"},
+				"default":     "status",
+				"description": "Action type: 'status' (default, fast, <10ms) returns structured data; 'message' sends to LLM for processing (slow, ~60s+)",
+			},
+			"message": map[string]any{
+				"type":        "string",
+				"description": "The message to send to the target node (only for action='message')",
+			},
+			"channel": map[string]any{
+				"type":        "string",
+				"description": "Source channel identifier for routing context (optional)",
+			},
+			"chat_id": map[string]any{
+				"type":        "string",
+				"description": "Source chat/conversation ID for continuity (optional)",
+			},
+			"sender_id": map[string]any{
+				"type":        "string",
+				"description": "Sender identity for audit and reply routing (optional)",
+			},
+			"trace_id": map[string]any{
+				"type":        "string",
+				"description": "Distributed trace ID for cross-node observability (optional)",
+			},
+		},
+		"required": []string{"node_id"},
+		"oneOf": []any{
+			map[string]any{
+				"properties": map[string]any{
+					"action": map[string]any{"const": "status"},
+				},
+			},
+			map[string]any{
+				"properties": map[string]any{
+					"action": map[string]any{"const": "message"},
+				},
+				"required": []string{"message"},
+			},
+		},
+	}
+}
+
+// Execute executes the swarm route tool.
+func (t *SwarmRouteTool) Execute(ctx context.Context, args map[string]any) *ToolResult {
+	if t.discovery == nil {
+		return ErrorResult("Swarm mode is not enabled")
+	}
+
+	nodeID, _ := args["node_id"].(string)
+	action, _ := args["action"].(string)
+	message, _ := args["message"].(string)
+
+	// Smart action inference:
+	// - If action is explicitly set, use it
+	// - If message is provided, use "message"
+	// - Otherwise, default to "status" (fast path)
+	if action == "" {
+		if message != "" {
+			action = "message"
+		} else {
+			action = "status"
+		}
+	}
+
+	if nodeID == "" {
+		return ErrorResult("node_id is required")
+	}
+
+	// For "message" action, content is required
+	if action == "message" && message == "" {
+		return ErrorResult(
+			"message is required when action='message'. For status queries, use action='status' instead.",
+		)
+	}
+
+	// Check if target is this node
+	if nodeID == t.localID {
+		return &ToolResult{
+			ForLLM:  fmt.Sprintf("Target node %s is this node. Processing locally.", nodeID),
+			ForUser: fmt.Sprintf("This request is already on node %s.", nodeID),
+			IsError: false,
+		}
+	}
+
+	// Find target node
+	members := t.discovery.Members()
+	var target *swarm.NodeWithState
+	for _, m := range members {
+		if m.Node.ID == nodeID {
+			target = m
+			break
+		}
+	}
+
+	if target == nil {
+		return ErrorResult(fmt.Sprintf("Node %s not found in cluster", nodeID))
+	}
+
+	// Check if target is available
+	if target.State.Status != swarm.NodeStatusAlive {
+		return ErrorResult(fmt.Sprintf("Node %s is not alive (status: %s)", nodeID, target.State.Status))
+	}
+
+	if target.Node.LoadScore > swarm.DefaultAvailableLoadThreshold {
+		return ErrorResult(fmt.Sprintf("Node %s is overloaded (load: %.0f%%)", nodeID, target.Node.LoadScore*100))
+	}
+
+	// Fast path: "status" action returns structured data directly
+	if action == "status" {
+		return t.executeStatusRequest(ctx, nodeID, target)
+	}
+
+	if t.sendMessageFn == nil {
+		return ErrorResult("inter-node messaging is not available")
+	}
+
+	// Extract optional context parameters for cross-node traceability.
+	channel, _ := args["channel"].(string)
+	chatID, _ := args["chat_id"].(string)
+	senderID, _ := args["sender_id"].(string)
+
+	logger.InfoCF("swarm", "Sending message to node", map[string]any{
+		"target":  nodeID,
+		"message": message,
+	})
+
+	response, err := t.sendMessageFn(ctx, nodeID, message, channel, chatID, senderID)
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("Failed to send message to node %s: %v", nodeID, err))
+	}
+
+	return &ToolResult{
+		ForLLM:  response,
+		ForUser: response,
+		IsError: false,
+	}
+}
+
+// executeStatusRequest sends a status action request to a node.
+func (t *SwarmRouteTool) executeStatusRequest(
+	ctx context.Context,
+	nodeID string,
+	target *swarm.NodeWithState,
+) *ToolResult {
+	if t.sendActionFn == nil {
+		return ErrorResult("inter-node actions not available")
+	}
+
+	logger.InfoCF("swarm", "Requesting status from node", map[string]any{
+		"target": nodeID,
+	})
+
+	response, err := t.sendActionFn(ctx, nodeID, "status")
+	if err != nil {
+		return ErrorResult(fmt.Sprintf("Failed to get status from node %s: %v", nodeID, err))
+	}
+
+	return &ToolResult{
+		ForLLM:  fmt.Sprintf("Node %s status:\n%s", nodeID, response),
+		ForUser: fmt.Sprintf("Node %s status:\n%s", nodeID, response),
+		IsError: false,
+	}
+}
+
+// ParseNodeMention extracts node ID from a message like "@node-id: message"
+func ParseNodeMention(message string) (nodeID, content string) {
+	message = strings.TrimSpace(message)
+
+	// Check for @node-id: pattern
+	if strings.HasPrefix(message, "@") {
+		rest := message[1:]
+		idx := strings.IndexAny(rest, ": \n")
+		if idx > 0 && rest[idx] == ':' {
+			nodeID = rest[:idx]
+			content = strings.TrimSpace(rest[idx+1:])
+			return nodeID, content
+		}
+	}
+
+	return "", message
+}
+
+// Helper functions
+
+func plural(n int) string {
+	if n == 1 {
+		return ""
+	}
+	return "s"
+}
+
+func formatDuration(d time.Duration) string {
+	if d < time.Second {
+		return fmt.Sprintf("%dms", d.Milliseconds())
+	}
+	if d < time.Minute {
+		return fmt.Sprintf("%.1fs", d.Seconds())
+	}
+	if d < time.Hour {
+		return fmt.Sprintf("%.1fm", d.Minutes())
+	}
+	return fmt.Sprintf("%.1fh", d.Hours())
+}