feat: execute LLM tool calls in parallel for faster response (#1070)

When the LLM returns multiple tool calls, they are now executed
concurrently using goroutines + sync.WaitGroup instead of sequentially.
Results are collected in an indexed slice and processed in original order
to preserve message ordering. MessageTool.sentInRound is changed to
atomic.Bool for thread safety.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

pkg/agent/loop.go

@@ -969,8 +969,22 @@ func (al *AgentLoop) runLLMIteration(
 		// Save assistant message with tool calls to session
 		agent.Sessions.AddFullMessage(opts.SessionKey, assistantMsg)
 
-		// Execute tool calls
+		// Execute tool calls in parallel
-		for _, tc := range normalizedToolCalls {
+		type indexedAgentResult struct {
+			result *tools.ToolResult
+			tc     providers.ToolCall
+		}
+
+		agentResults := make([]indexedAgentResult, len(normalizedToolCalls))
+		var wg sync.WaitGroup
+
+		for i, tc := range normalizedToolCalls {
+			agentResults[i].tc = tc
+
+			wg.Add(1)
+			go func(idx int, tc providers.ToolCall) {
+				defer wg.Done()
+
 				argsJSON, _ := json.Marshal(tc.Arguments)
 				argsPreview := utils.Truncate(string(argsJSON), 200)
 				logger.InfoCF("agent", fmt.Sprintf("Tool call: %s(%s)", tc.Name, argsPreview),
@@ -981,12 +995,7 @@ func (al *AgentLoop) runLLMIteration(
 					})
 
 				// Create async callback for tools that implement AsyncTool
-			// NOTE: Following openclaw's design, async tools do NOT send results directly to users.
-			// Instead, they notify the agent via PublishInbound, and the agent decides
-			// whether to forward the result to the user (in processSystemMessage).
 				asyncCallback := func(callbackCtx context.Context, result *tools.ToolResult) {
-				// Log the async completion but don't send directly to user
-				// The agent will handle user notification via processSystemMessage
 					if !result.Silent && result.ForUser != "" {
 						logger.InfoCF("agent", "Async tool completed, agent will handle notification",
 							map[string]any{
@@ -1004,27 +1013,32 @@ func (al *AgentLoop) runLLMIteration(
 					opts.ChatID,
 					asyncCallback,
 				)
+				agentResults[idx].result = toolResult
+			}(i, tc)
+		}
+		wg.Wait()
 
+		// Process results in original order (send to user, save to session)
+		for _, r := range agentResults {
 			// Send ForUser content to user immediately if not Silent
-			if !toolResult.Silent && toolResult.ForUser != "" && opts.SendResponse {
+			if !r.result.Silent && r.result.ForUser != "" && opts.SendResponse {
 				al.bus.PublishOutbound(ctx, bus.OutboundMessage{
 					Channel: opts.Channel,
 					ChatID:  opts.ChatID,
-					Content: toolResult.ForUser,
+					Content: r.result.ForUser,
 				})
 				logger.DebugCF("agent", "Sent tool result to user",
 					map[string]any{
-						"tool":        tc.Name,
+						"tool":        r.tc.Name,
-						"content_len": len(toolResult.ForUser),
+						"content_len": len(r.result.ForUser),
 					})
 			}
 
 			// If tool returned media refs, publish them as outbound media
-			if len(toolResult.Media) > 0 && opts.SendResponse {
+			if len(r.result.Media) > 0 && opts.SendResponse {
-				parts := make([]bus.MediaPart, 0, len(toolResult.Media))
+				parts := make([]bus.MediaPart, 0, len(r.result.Media))
-				for _, ref := range toolResult.Media {
+				for _, ref := range r.result.Media {
 					part := bus.MediaPart{Ref: ref}
-					// Populate metadata from MediaStore when available
 					if al.mediaStore != nil {
 						if _, meta, err := al.mediaStore.ResolveWithMeta(ref); err == nil {
 							part.Filename = meta.Filename
@@ -1042,15 +1056,15 @@ func (al *AgentLoop) runLLMIteration(
 			}
 
 			// Determine content for LLM based on tool result
-			contentForLLM := toolResult.ForLLM
+			contentForLLM := r.result.ForLLM
-			if contentForLLM == "" && toolResult.Err != nil {
+			if contentForLLM == "" && r.result.Err != nil {
-				contentForLLM = toolResult.Err.Error()
+				contentForLLM = r.result.Err.Error()
 			}
 
 			toolResultMsg := providers.Message{
 				Role:       "tool",
 				Content:    contentForLLM,
-				ToolCallID: tc.ID,
+				ToolCallID: r.tc.ID,
 			}
 			messages = append(messages, toolResultMsg)
 

pkg/tools/message.go

@@ -3,6 +3,7 @@ package tools
 import (
 	"context"
 	"fmt"
+	"sync/atomic"
 )
 
 type SendCallback func(channel, chatID, content string) error
@@ -11,7 +12,7 @@ type MessageTool struct {
 	sendCallback   SendCallback
 	defaultChannel string
 	defaultChatID  string
-	sentInRound    bool // Tracks whether a message was sent in the current processing round
+	sentInRound    atomic.Bool // Tracks whether a message was sent in the current processing round
 }
 
 func NewMessageTool() *MessageTool {
@@ -50,12 +51,12 @@ func (t *MessageTool) Parameters() map[string]any {
 func (t *MessageTool) SetContext(channel, chatID string) {
 	t.defaultChannel = channel
 	t.defaultChatID = chatID
-	t.sentInRound = false // Reset send tracking for new processing round
+	t.sentInRound.Store(false) // Reset send tracking for new processing round
 }
 
 // HasSentInRound returns true if the message tool sent a message during the current round.
 func (t *MessageTool) HasSentInRound() bool {
-	return t.sentInRound
+	return t.sentInRound.Load()
 }
 
 func (t *MessageTool) SetSendCallback(callback SendCallback) {
@@ -94,7 +95,7 @@ func (t *MessageTool) Execute(ctx context.Context, args map[string]any) *ToolRes
 		}
 	}
 
-	t.sentInRound = true
+	t.sentInRound.Store(true)
 	// Silent: user already received the message directly
 	return &ToolResult{
 		ForLLM: fmt.Sprintf("Message sent to %s:%s", channel, chatID),

pkg/tools/toolloop.go

@@ -10,6 +10,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"sync"
 
 	"github.com/sipeed/picoclaw/pkg/logger"
 	"github.com/sipeed/picoclaw/pkg/providers"
@@ -121,8 +122,22 @@ func RunToolLoop(
 		}
 		messages = append(messages, assistantMsg)
 
-		// 7. Execute tool calls
+		// 7. Execute tool calls in parallel
-		for _, tc := range normalizedToolCalls {
+		type indexedResult struct {
+			result *ToolResult
+			tc     providers.ToolCall
+		}
+
+		results := make([]indexedResult, len(normalizedToolCalls))
+		var wg sync.WaitGroup
+
+		for i, tc := range normalizedToolCalls {
+			results[i].tc = tc
+
+			wg.Add(1)
+			go func(idx int, tc providers.ToolCall) {
+				defer wg.Done()
+
 				argsJSON, _ := json.Marshal(tc.Arguments)
 				argsPreview := utils.Truncate(string(argsJSON), 200)
 				logger.InfoCF("toolloop", fmt.Sprintf("Tool call: %s(%s)", tc.Name, argsPreview),
@@ -131,27 +146,29 @@ func RunToolLoop(
 						"iteration": iteration,
 					})
 
-			// Execute tool (no async callback for subagents - they run independently)
 				var toolResult *ToolResult
 				if config.Tools != nil {
 					toolResult = config.Tools.ExecuteWithContext(ctx, tc.Name, tc.Arguments, channel, chatID, nil)
 				} else {
 					toolResult = ErrorResult("No tools available")
 				}
+				results[idx].result = toolResult
+			}(i, tc)
+		}
+		wg.Wait()
 
-			// Determine content for LLM
+		// Append results in original order
-			contentForLLM := toolResult.ForLLM
+		for _, r := range results {
-			if contentForLLM == "" && toolResult.Err != nil {
+			contentForLLM := r.result.ForLLM
-				contentForLLM = toolResult.Err.Error()
+			if contentForLLM == "" && r.result.Err != nil {
+				contentForLLM = r.result.Err.Error()
 			}
 
-			// Add tool result message
+			messages = append(messages, providers.Message{
-			toolResultMsg := providers.Message{
 				Role:       "tool",
 				Content:    contentForLLM,
-				ToolCallID: tc.ID,
+				ToolCallID: r.tc.ID,
-			}
+			})
-			messages = append(messages, toolResultMsg)
 		}
 	}