fix(tool-feedback): unify fallback and single-message delivery

docs/channels/discord/README.md

@@ -54,7 +54,7 @@ Discord can show three different kinds of "working" feedback:
 
 ```text
 🔧 `web_search`
-{"query":"picoclaw release notes"}
+Checking the latest PicoClaw release notes before I answer.
 ```
 
 If you only see `Bot is typing`, check that `placeholder.enabled` or `tool_feedback.enabled` is actually set in your runtime config.

pkg/agent/loop.go

@@ -851,13 +851,10 @@ func outboundMessageForTurnWithKind(ts *turnState, content, kind string) bus.Out
 	return msg
 }
 
-func previousAssistantContent(messages []providers.Message) string {
+func latestUserContent(messages []providers.Message) string {
 	for i := len(messages) - 1; i >= 0; i-- {
 		msg := messages[i]
-		if msg.Role == "user" {
-			break
-		}
-		if msg.Role != "assistant" {
+		if msg.Role != "user" {
 			continue
 		}
 		if content := strings.TrimSpace(msg.Content); content != "" {
@@ -883,7 +880,10 @@ func toolFeedbackExplanationFromResponse(
 		explanation = strings.TrimSpace(response.ReasoningContent)
 	}
 	if explanation == "" {
-		explanation = previousAssistantContent(messages)
+		explanation = latestUserContent(messages)
+		if explanation != "" {
+			explanation = utils.ToolFeedbackContinuationHint + ": " + explanation
+		}
 	}
 	return utils.Truncate(explanation, maxLen)
 }
@@ -2738,6 +2738,12 @@ turnLoop:
 		for _, tc := range normalizedToolCalls {
 			argumentsJSON, _ := json.Marshal(tc.Arguments)
 			extraContent := tc.ExtraContent
+			if strings.TrimSpace(toolFeedbackExplanation) != "" {
+				if extraContent == nil {
+					extraContent = &providers.ExtraContent{}
+				}
+				extraContent.ToolFeedbackExplanation = toolFeedbackExplanation
+			}
 			thoughtSignature := ""
 			if tc.Function != nil {
 				thoughtSignature = tc.Function.ThoughtSignature

pkg/agent/loop_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/routing"
 	"github.com/sipeed/picoclaw/pkg/session"
 	"github.com/sipeed/picoclaw/pkg/tools"
+	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
 type fakeChannel struct{ id string }
@@ -1827,7 +1828,7 @@ func TestToolFeedbackExplanationFromResponse_FallsBackToReasoningContent(t *test
 	}
 }
 
-func TestToolFeedbackExplanationFromResponse_UsesPreviousAssistantContentAsLastResort(t *testing.T) {
+func TestToolFeedbackExplanationFromResponse_UsesLatestUserContentAsLastResort(t *testing.T) {
 	response := &providers.LLMResponse{
 		Content:          "",
 		ReasoningContent: "",
@@ -1835,12 +1836,14 @@ func TestToolFeedbackExplanationFromResponse_UsesPreviousAssistantContentAsLastR
 	messages := []providers.Message{
 		{Role: "user", Content: "check file"},
 		{Role: "assistant", Content: "Previous turn explanation"},
+		{Role: "user", Content: "Inspect README.md and update the config example."},
 		{Role: "tool", Content: "tool output", ToolCallID: "call_1"},
 	}
 
 	got := toolFeedbackExplanationFromResponse(response, messages, 300)
-	if got != "Previous turn explanation" {
-		t.Fatalf("toolFeedbackExplanationFromResponse() = %q, want previous assistant content", got)
+	want := utils.ToolFeedbackContinuationHint + ": Inspect README.md and update the config example."
+	if got != want {
+		t.Fatalf("toolFeedbackExplanationFromResponse() = %q, want latest user content fallback", got)
 	}
 }
 
@@ -3744,8 +3747,14 @@ func TestProcessMessage_PublishesToolFeedbackWhenEnabled(t *testing.T) {
 		if !strings.Contains(outbound.Content, "`read_file`") {
 			t.Fatalf("tool feedback content = %q, want read_file summary", outbound.Content)
 		}
-		if strings.Contains(outbound.Content, "Why this tool should be executed") {
-			t.Fatalf("tool feedback content = %q, want no fallback explanation", outbound.Content)
+		if !strings.Contains(outbound.Content, utils.ToolFeedbackContinuationHint) {
+			t.Fatalf("tool feedback content = %q, want continuation hint fallback", outbound.Content)
+		}
+		if !strings.Contains(outbound.Content, "check tool feedback") {
+			t.Fatalf("tool feedback content = %q, want current user intent fallback", outbound.Content)
+		}
+		if strings.Contains(outbound.Content, "Previous turn explanation") {
+			t.Fatalf("tool feedback content = %q, want no previous assistant fallback", outbound.Content)
 		}
 		if outbound.AgentID != "main" {
 			t.Fatalf("tool feedback agent_id = %q, want main", outbound.AgentID)

pkg/channels/manager.go

@@ -26,6 +26,7 @@ import (
 	"github.com/sipeed/picoclaw/pkg/health"
 	"github.com/sipeed/picoclaw/pkg/logger"
 	"github.com/sipeed/picoclaw/pkg/media"
+	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
 const (
@@ -820,14 +821,16 @@ func (m *Manager) runWorker(ctx context.Context, name string, w *channelWorker)
 			if m.config != nil && m.config.Agents.Defaults.SplitOnMarker {
 				if markerChunks := SplitByMarker(msg.Content); len(markerChunks) > 1 {
 					for _, chunk := range markerChunks {
-						chunks = append(chunks, splitByLength(chunk, maxLen)...)
+						chunkMsg := msg
+						chunkMsg.Content = chunk
+						chunks = append(chunks, splitOutboundMessageContent(chunkMsg, maxLen)...)
 					}
 				}
 			}
 
 			// Step 2: Fallback to length-based splitting if no chunks from marker
 			if len(chunks) == 0 {
-				chunks = splitByLength(msg.Content, maxLen)
+				chunks = splitOutboundMessageContent(msg, maxLen)
 			}
 
 			// Step 3: Send all chunks
@@ -842,12 +845,16 @@ func (m *Manager) runWorker(ctx context.Context, name string, w *channelWorker)
 	}
 }
 
-// splitByLength splits content by maxLen if needed, otherwise returns single chunk.
-func splitByLength(content string, maxLen int) []string {
-	if maxLen > 0 && len([]rune(content)) > maxLen {
-		return SplitMessage(content, maxLen)
+// splitOutboundMessageContent splits regular outbound content by maxLen, but
+// keeps tool feedback in a single message by truncating the explanation body.
+func splitOutboundMessageContent(msg bus.OutboundMessage, maxLen int) []string {
+	if maxLen > 0 && len([]rune(msg.Content)) > maxLen {
+		if outboundMessageIsToolFeedback(msg) {
+			return []string{utils.FitToolFeedbackMessage(msg.Content, maxLen)}
 		}
-	return []string{content}
+		return SplitMessage(msg.Content, maxLen)
+	}
+	return []string{msg.Content}
 }
 
 // sendWithRetry sends a message through the channel with rate limiting and
@@ -1311,13 +1318,16 @@ func (m *Manager) SendMessage(ctx context.Context, msg bus.OutboundMessage) erro
 	if mlp, ok := w.ch.(MessageLengthProvider); ok {
 		maxLen = mlp.MaxMessageLength()
 	}
-	if maxLen > 0 && len([]rune(msg.Content)) > maxLen {
-		for _, chunk := range SplitMessage(msg.Content, maxLen) {
+	if chunks := splitOutboundMessageContent(msg, maxLen); len(chunks) > 1 {
+		for _, chunk := range chunks {
 			chunkMsg := msg
 			chunkMsg.Content = chunk
 			m.sendWithRetry(ctx, channelName, w, chunkMsg)
 		}
 	} else {
+		if len(chunks) == 1 {
+			msg.Content = chunks[0]
+		}
 		m.sendWithRetry(ctx, channelName, w, msg)
 	}
 	return nil

pkg/channels/manager_test.go

@@ -13,6 +13,7 @@ import (
 	"golang.org/x/time/rate"
 
 	"github.com/sipeed/picoclaw/pkg/bus"
+	"github.com/sipeed/picoclaw/pkg/utils"
 )
 
 // mockChannel is a test double that delegates Send to a configurable function.
@@ -907,6 +908,30 @@ func TestPreSendMedia_DismissesTrackedMessage(t *testing.T) {
 	}
 }
 
+func TestSplitOutboundMessageContent_ToolFeedbackTruncatesInsteadOfSplitting(t *testing.T) {
+	msg := testOutboundMessage(bus.OutboundMessage{
+		Channel: "test",
+		ChatID:  "123",
+		Content: "\U0001f527 `read_file`\nRead README.md first to confirm the current project structure before editing the config example.",
+		Context: bus.InboundContext{
+			Channel: "test",
+			ChatID:  "123",
+			Raw: map[string]string{
+				"message_kind": "tool_feedback",
+			},
+		},
+	})
+
+	chunks := splitOutboundMessageContent(msg, 40)
+	if len(chunks) != 1 {
+		t.Fatalf("len(chunks) = %d, want 1", len(chunks))
+	}
+	want := utils.FitToolFeedbackMessage(msg.Content, 40)
+	if chunks[0] != want {
+		t.Fatalf("chunk = %q, want %q", chunks[0], want)
+	}
+}
+
 func TestPreSend_PlaceholderEditFails_FallsThrough(t *testing.T) {
 	m := newTestManager()
 

pkg/config/config.go

@@ -286,7 +286,7 @@ func (d *AgentDefaults) GetMaxMediaSize() int {
 	return DefaultMaxMediaSize
 }
 
-// GetToolFeedbackMaxArgsLength returns the max args preview length for tool feedback messages.
+// GetToolFeedbackMaxArgsLength returns the max visible text length for tool feedback messages.
 func (d *AgentDefaults) GetToolFeedbackMaxArgsLength() int {
 	if d.ToolFeedback.MaxArgsLength > 0 {
 		return d.ToolFeedback.MaxArgsLength

pkg/providers/protocoltypes/types.go

@@ -12,6 +12,7 @@ type ToolCall struct {
 
 type ExtraContent struct {
 	Google                  *GoogleExtra `json:"google,omitempty"`
+	ToolFeedbackExplanation string       `json:"tool_feedback_explanation,omitempty"`
 }
 
 type GoogleExtra struct {

pkg/utils/tool_feedback.go

@@ -5,6 +5,8 @@ import (
 	"strings"
 )
 
+const ToolFeedbackContinuationHint = "Continuing the current task."
+
 // FormatToolFeedbackMessage renders the model-provided explanation for why a
 // tool is being executed. When the model does not provide one, it keeps only
 // the tool line and does not expose raw arguments or fallback text.
@@ -21,3 +23,35 @@ func FormatToolFeedbackMessage(toolName, explanation string) string {
 
 	return fmt.Sprintf("\U0001f527 `%s`\n%s", toolName, explanation)
 }
+
+// FitToolFeedbackMessage keeps tool feedback within a single outbound message.
+// It preserves the first line when possible and truncates the explanation body
+// instead of letting the message be split into multiple chunks.
+func FitToolFeedbackMessage(content string, maxLen int) string {
+	content = strings.TrimSpace(content)
+	if content == "" || maxLen <= 0 {
+		return ""
+	}
+	if len([]rune(content)) <= maxLen {
+		return content
+	}
+
+	firstLine, rest, hasRest := strings.Cut(content, "\n")
+	firstLine = strings.TrimSpace(firstLine)
+	rest = strings.TrimSpace(rest)
+
+	if !hasRest || rest == "" {
+		return Truncate(firstLine, maxLen)
+	}
+
+	if len([]rune(firstLine)) >= maxLen {
+		return Truncate(firstLine, maxLen)
+	}
+
+	remaining := maxLen - len([]rune(firstLine)) - 1
+	if remaining <= 0 {
+		return Truncate(firstLine, maxLen)
+	}
+
+	return firstLine + "\n" + Truncate(rest, remaining)
+}

pkg/utils/tool_feedback_test.go

@@ -25,3 +25,19 @@ func TestFormatToolFeedbackMessage_EmptyToolNameOmitsToolLine(t *testing.T) {
 		t.Fatalf("FormatToolFeedbackMessage() = %q, want %q", got, want)
 	}
 }
+
+func TestFitToolFeedbackMessage_TruncatesBodyWithinSingleMessage(t *testing.T) {
+	got := FitToolFeedbackMessage("\U0001f527 `read_file`\nRead README.md first to confirm the current project structure.", 40)
+	want := "\U0001f527 `read_file`\nRead README.md first to..."
+	if got != want {
+		t.Fatalf("FitToolFeedbackMessage() = %q, want %q", got, want)
+	}
+}
+
+func TestFitToolFeedbackMessage_TruncatesSingleLineMessage(t *testing.T) {
+	got := FitToolFeedbackMessage("\U0001f527 `read_file`", 10)
+	want := "\U0001f527 `read..."
+	if got != want {
+		t.Fatalf("FitToolFeedbackMessage() = %q, want %q", got, want)
+	}
+}

web/backend/api/session.go

@@ -529,31 +529,23 @@ func visibleAssistantToolSummaryMessages(
 	messages := make([]sessionChatMessage, 0, len(toolCalls))
 	for _, tc := range toolCalls {
 		name := tc.Name
-		argsJSON := ""
 		if tc.Function != nil {
 			if name == "" {
 				name = tc.Function.Name
 			}
-			argsJSON = tc.Function.Arguments
 		}
 
 		if strings.TrimSpace(name) == "" {
 			continue
 		}
 
-		if strings.TrimSpace(argsJSON) == "" && len(tc.Arguments) > 0 {
-			if encodedArgs, err := json.Marshal(tc.Arguments); err == nil {
-				argsJSON = string(encodedArgs)
-			}
-		}
-
-		argsPreview := strings.TrimSpace(argsJSON)
-		if argsPreview == "" {
-			argsPreview = "{}"
+		explanation := ""
+		if tc.ExtraContent != nil {
+			explanation = strings.TrimSpace(tc.ExtraContent.ToolFeedbackExplanation)
 		}
 		messages = append(messages, sessionChatMessage{
 			Role:    "assistant",
-			Content: utils.FormatToolFeedbackMessage(name, utils.Truncate(argsPreview, toolFeedbackMaxArgsLength)),
+			Content: utils.FormatToolFeedbackMessage(name, utils.Truncate(explanation, toolFeedbackMaxArgsLength)),
 		})
 	}
 

web/backend/api/session_test.go

@@ -629,6 +629,7 @@ func TestHandleGetSession_UsesConfiguredToolFeedbackMaxArgsLength(t *testing.T)
 	}
 
 	argsJSON := `{"path":"README.md","start_line":1,"end_line":10,"extra":"abcdefghijklmnopqrstuvwxyz"}`
+	explanation := "Read README.md first to confirm the current project structure before editing the config example."
 	sessionKey := picoSessionPrefix + "detail-tool-summary-max-args"
 	err = store.AddFullMessage(nil, sessionKey, providers.Message{Role: "user", Content: "check file"})
 	if err != nil {
@@ -643,6 +644,9 @@ func TestHandleGetSession_UsesConfiguredToolFeedbackMaxArgsLength(t *testing.T)
 				Name:      "read_file",
 				Arguments: argsJSON,
 			},
+			ExtraContent: &providers.ExtraContent{
+				ToolFeedbackExplanation: explanation,
+			},
 		}},
 	})
 	if err != nil {
@@ -675,7 +679,7 @@ func TestHandleGetSession_UsesConfiguredToolFeedbackMaxArgsLength(t *testing.T)
 		t.Fatalf("len(resp.Messages) = %d, want at least 2", len(resp.Messages))
 	}
 
-	wantPreview := utils.Truncate(argsJSON, 20)
+	wantPreview := utils.Truncate(explanation, 20)
 	if !strings.Contains(resp.Messages[1].Content, wantPreview) {
 		t.Fatalf("tool summary = %q, want preview %q", resp.Messages[1].Content, wantPreview)
 	}

web/frontend/src/i18n/locales/en.json

@@ -592,9 +592,9 @@
       "split_on_marker": "Chatty Mode",
       "split_on_marker_hint": "Split long messages into short ones like real human chatting.",
       "tool_feedback_enabled": "Tool Feedback",
-      "tool_feedback_enabled_hint": "Send a short tool-call preview into the current chat before each tool execution.",
-      "tool_feedback_max_args_length": "Tool Feedback Args Preview Length",
-      "tool_feedback_max_args_length_hint": "Maximum number of argument characters shown in each tool feedback message. Set to 0 to use the default.",
+      "tool_feedback_enabled_hint": "Send a short execution note into the current chat before each tool runs.",
+      "tool_feedback_max_args_length": "Tool Feedback Length",
+      "tool_feedback_max_args_length_hint": "Maximum number of characters shown in each tool feedback message. Set to 0 to use the default.",
       "exec_enabled": "Allow Commands",
       "exec_enabled_hint": "Enable or disable command execution for the app. When disabled, no command requests will run.",
       "allow_remote": "Allow Remote Commands",

web/frontend/src/i18n/locales/zh.json

@@ -592,9 +592,9 @@
       "split_on_marker": "连续短消息",
       "split_on_marker_hint": "像真人聊天一样，把长难句拆成多条短消息快速发出",
       "tool_feedback_enabled": "工具反馈",
-      "tool_feedback_enabled_hint": "在每次执行工具前，先向当前会话发送一条简短的工具调用预览",
-      "tool_feedback_max_args_length": "工具反馈参数预览长度",
-      "tool_feedback_max_args_length_hint": "每条工具反馈消息中展示的参数字符上限。设为 0 时使用默认值",
+      "tool_feedback_enabled_hint": "在每次执行工具前，先向当前会话发送一条简短的执行说明",
+      "tool_feedback_max_args_length": "工具反馈长度",
+      "tool_feedback_max_args_length_hint": "每条工具反馈消息中展示的字符上限。设为 0 时使用默认值",
       "exec_enabled": "允许命令执行",
       "exec_enabled_hint": "控制应用是否允许执行命令。关闭后，所有命令请求都不会执行",
       "allow_remote": "允许远程命令执行",