feat: update config, session manager, tools dag and subagent

pkg/config/config.go

@@ -144,6 +144,14 @@ type ContinuityRetentionConfig struct {
 	FailureKeepMessages int `json:"failure_keep_messages" env:"DRAGONSCALE_AGENTS_DEFAULTS_CONTINUITY_RETENTION_FAILURE_KEEP_MESSAGES"`
 }
 
+// CompactionConfig controls the dual-threshold compaction control loop (LCM ADR-002).
+type CompactionConfig struct {
+	// SoftThresholdPct triggers async background compaction (default 70).
+	SoftThresholdPct int `json:"soft_threshold_pct" env:"DRAGONSCALE_AGENTS_DEFAULTS_COMPACTION_SOFT_THRESHOLD_PCT"`
+	// HardThresholdPct triggers synchronous blocking compaction (default 90).
+	HardThresholdPct int `json:"hard_threshold_pct" env:"DRAGONSCALE_AGENTS_DEFAULTS_COMPACTION_HARD_THRESHOLD_PCT"`
+}
+
 type AgentDefaults struct {
 	// Sandbox is the directory for agent file operations (tools sandbox).
 	// Defaults to $XDG_DATA_HOME/dragonscale/sandbox when empty.
@@ -155,6 +163,7 @@ type AgentDefaults struct {
 	Temperature         float64                   `json:"temperature" env:"DRAGONSCALE_AGENTS_DEFAULTS_TEMPERATURE"`
 	MaxToolIterations   int                       `json:"max_tool_iterations" env:"DRAGONSCALE_AGENTS_DEFAULTS_MAX_TOOL_ITERATIONS"`
 	ContinuityRetention ContinuityRetentionConfig `json:"continuity_retention"`
+	Compaction          CompactionConfig          `json:"compaction"`
 
 	// Deprecated: Use Sandbox instead. Kept for backward compatibility during migration.
 	Workspace           string `json:"workspace,omitempty" env:"DRAGONSCALE_AGENTS_DEFAULTS_WORKSPACE"`
@@ -373,6 +382,10 @@ func DefaultConfig() *Config {
 					TargetContextRatio:  0.10,
 					FailureKeepMessages: 10,
 				},
+				Compaction: CompactionConfig{
+					SoftThresholdPct: 70,
+					HardThresholdPct: 90,
+				},
 			},
 		},
 		Channels: ChannelsConfig{

pkg/session/manager.go

@@ -402,6 +402,27 @@ func (sm *SessionManager) persistMessageToDelegate(sessionKey string, msg messag
 			map[string]interface{}{"session": sessionKey, "error": err.Error()})
 		return
 	}
+
+	// Dual-write: persist verbatim copy to immutable store (LCM ADR-001).
+	immutableWriter, ok := sm.delegate.(interface {
+		InsertImmutableMessage(ctx context.Context, msg *memory.ImmutableMessage) error
+	})
+	if ok {
+		imMsg := &memory.ImmutableMessage{
+			ID:            ids.New(),
+			SessionKey:    sessionKey,
+			Role:          msg.Role,
+			Content:       msg.Content,
+			ToolCallID:    msg.ToolCallID,
+			ToolCalls:     toolCallsJSON(msg),
+			TokenEstimate: estimateTokensSimple(msg.Content),
+		}
+		if err := immutableWriter.InsertImmutableMessage(ctx, imMsg); err != nil {
+			logger.WarnCF("session", "Failed to persist immutable message",
+				map[string]interface{}{"session": sessionKey, "error": err.Error()})
+		}
+	}
+
 	priorPtr, _ := sm.loadProjectionPointer(ctx, sessionKey)
 	newPtr := advancePointer(priorPtr, item.ID, now)
 	if err := sm.persistProjectionPointer(ctx, sessionKey, newPtr); err != nil {
@@ -729,3 +750,18 @@ func (sm *SessionManager) SetHistory(key string, history []messages.Message) {
 		session.Updated = time.Now()
 	}
 }
+
+func toolCallsJSON(msg messages.Message) string {
+	if len(msg.ToolCalls) == 0 {
+		return ""
+	}
+	b, err := jsonv2.Marshal(msg.ToolCalls)
+	if err != nil {
+		return ""
+	}
+	return string(b)
+}
+
+func estimateTokensSimple(content string) int {
+	return (len(content) + 3) / 4
+}

pkg/tools/dag.go

@@ -29,7 +29,7 @@ type DAGToolDeps struct {
 	SessionFn func() string // returns current session key
 }
 
-func recallRowToItem(row memsqlc.RecallItem) *memory.RecallItem {
+func recallRowToItem(row memsqlc.ListSessionMessagesPagedRow) *memory.RecallItem {
 	return &memory.RecallItem{
 		ID:         row.ID,
 		AgentID:    row.AgentID,

pkg/tools/subagent.go

@@ -3,6 +3,7 @@ package tools
 import (
 	"context"
 	"fmt"
+	"log/slog"
 	"strings"
 	"sync"
 	"time"
@@ -186,6 +187,14 @@ func (sm *SubagentManager) Spawn(ctx context.Context, task, label, delegatedScop
 			return "", fmt.Errorf("nested delegation requires delegated_scope and kept_work")
 		}
 	}
+	if keptWork != "" {
+		slog.Debug("delegation scope-reduction",
+			"parent_depth", parentDepth,
+			"child_depth", childDepth,
+			"kept_work", keptWork,
+			"delegated_scope", delegatedScope,
+		)
+	}
 	if sm.runLoop == nil {
 		sm.mu.Unlock()
 		return "", ErrRunLoopNotConfigured
@@ -461,6 +470,14 @@ func (t *SubagentTool) Execute(ctx context.Context, args map[string]interface{})
 			return ErrorResult("nested delegation requires delegated_scope and kept_work")
 		}
 	}
+	if keptWork != "" {
+		slog.Debug("delegation scope-reduction",
+			"parent_depth", parentDepth,
+			"child_depth", childDepth,
+			"kept_work", keptWork,
+			"delegated_scope", delegatedScope,
+		)
+	}
 
 	systemPrompt := "You are a subagent operating with main-loop control flow. Execute actions via tools, call discovered tools directly, and provide a clear concise result."