feat(simulate): t shows and hides tool output, hidden by default

Tool outputs are payloads written for the model, not for a reader: a
policy blob or a lookup table's worth of JSON between two spoken turns
buries the conversation the job is about. Keep them off the transcript
and put them behind t, whole rather than clipped, since a clipped payload
answers nothing about why a job failed on a tool call.

The tool call itself stays on the transcript either way — which tool ran,
with a preview of its arguments, is part of reading what the agent did.

Author: u9g

cmd/lk/simulate_tui.go

@@ -226,9 +226,9 @@ type simulateModel struct {
 	detailPrinted string
 	detailWidth   int
 	showLogs      bool
-	// tool call arguments and outputs are clipped to a preview in the
-	// transcript; showToolDetail renders them whole instead
-	showToolDetail  bool
+	// tool outputs are off the transcript unless asked for: they are payloads
+	// written for the model, and at full length they bury the conversation
+	showToolOutput  bool
 	logScrollOff    int
 	logPinned       bool
 	logPinnedTotal  int
@@ -901,7 +901,7 @@ func (m *simulateModel) handleKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		m.logPinned = false
 	case "t":
 		if m.detailJobID != "" {
-			m.showToolDetail = !m.showToolDetail
+			m.showToolOutput = !m.showToolOutput
 		}
 	case "d":
 		if m.detailJobID == "" && m.hasDescription() {
@@ -1875,15 +1875,18 @@ func (m *simulateModel) renderChatTranscript(jobID string) string {
 		case *agent.ChatContext_ChatItem_FunctionCall:
 			fc := v.FunctionCall
 			ensureAgentBlock()
-			m.writeToolItem(&b, fmt.Sprintf("ƒ %s(%s)", fc.Name, m.toolValue(fc.Arguments)), wrapWidth)
+			writeToolItem(&b, fmt.Sprintf("ƒ %s(%s)", fc.Name, clipToolValue(fc.Arguments)), wrapWidth)
 		case *agent.ChatContext_ChatItem_FunctionCallOutput:
+			if !m.showToolOutput {
+				continue
+			}
 			fco := v.FunctionCallOutput
 			output := strings.TrimSpace(fco.Output)
 			if output == "" {
 				continue
 			}
 			ensureAgentBlock()
-			m.writeToolItem(&b, "→ "+m.toolValue(output), wrapWidth)
+			writeToolItem(&b, "→ "+output, wrapWidth)
 		case *agent.ChatContext_ChatItem_AgentHandoff:
 			h := v.AgentHandoff
 			old := ""
@@ -1898,36 +1901,29 @@ func (m *simulateModel) renderChatTranscript(jobID string) string {
 	return b.String()
 }
 
-// toolPreviewLen is how much of a tool call's arguments or output the
-// transcript shows when tool detail is collapsed — enough to tell two calls
-// apart without a lookup table's worth of JSON burying the conversation.
+// toolPreviewLen is how much of a tool call's arguments the transcript shows —
+// enough to tell two calls apart without a lookup table's worth of JSON burying
+// the conversation. Tool outputs are shown whole, or not at all.
 const toolPreviewLen = 80
 
-// toolValue is a tool argument blob or output as the transcript should carry
-// it: clipped to a preview, or whole when tool detail is expanded.
-func (m *simulateModel) toolValue(s string) string {
-	if m.showToolDetail || len(s) <= toolPreviewLen {
+// clipToolValue is a tool argument blob as the transcript carries it.
+func clipToolValue(s string) string {
+	if len(s) <= toolPreviewLen {
 		return s
 	}
-	// clip on a rune boundary; arguments and outputs carry guest names,
-	// currency symbols, and quoted speech
+	// clip on a rune boundary; arguments carry guest names, currency symbols,
+	// and quoted speech
 	clipped := s[:toolPreviewLen]
 	for len(clipped) > 0 && !utf8.ValidString(clipped) {
 		clipped = clipped[:len(clipped)-1]
 	}
 	return clipped + "..."
 }
 
-// writeToolItem appends one tool line to b. Collapsed, it is a single row and
-// the terminal deals with any overflow. Expanded, it wraps to the transcript's
-// measure with its continuations indented under the marker, so a long output
-// stays readable as a block instead of one run-on row.
-func (m *simulateModel) writeToolItem(b *strings.Builder, text string, wrapWidth int) {
-	if !m.showToolDetail {
-		b.WriteString(dimStyle.Render("      " + text))
-		b.WriteString("\n")
-		return
-	}
+// writeToolItem appends one tool line to b, wrapped to the transcript's measure
+// with its continuations indented under the marker, so a long output stays
+// readable as a block instead of one run-on row.
+func writeToolItem(b *strings.Builder, text string, wrapWidth int) {
 	for i, line := range wrapLines(text, wrapWidth-2) {
 		indent := "      "
 		if i > 0 {
@@ -1938,10 +1934,9 @@ func (m *simulateModel) writeToolItem(b *strings.Builder, text string, wrapWidth
 	}
 }
 
-// hasToolDetail reports whether the open job's transcript holds anything the
-// tool-detail toggle would reveal, so the hint is only offered when it does
-// something.
-func (m *simulateModel) hasToolDetail(jobID string) bool {
+// hasToolOutput reports whether the open job's transcript holds a tool output,
+// so the hint is only offered when the toggle would show something.
+func (m *simulateModel) hasToolOutput(jobID string) bool {
 	if m.summary == nil || m.summary.ChatHistory == nil {
 		return false
 	}
@@ -1950,13 +1945,8 @@ func (m *simulateModel) hasToolDetail(jobID string) bool {
 		return false
 	}
 	for _, item := range chatCtx.Items {
-		switch v := item.Item.(type) {
-		case *agent.ChatContext_ChatItem_FunctionCall:
-			if len(v.FunctionCall.Arguments) > toolPreviewLen {
-				return true
-			}
-		case *agent.ChatContext_ChatItem_FunctionCallOutput:
-			if len(strings.TrimSpace(v.FunctionCallOutput.Output)) > toolPreviewLen {
+		if v, ok := item.Item.(*agent.ChatContext_ChatItem_FunctionCallOutput); ok {
+			if strings.TrimSpace(v.FunctionCallOutput.Output) != "" {
 				return true
 			}
 		}
@@ -2083,11 +2073,11 @@ func (m *simulateModel) renderHint() string {
 	case m.detailJobID != "":
 		// the job view is in the terminal's scrollback, which scrolls itself
 		parts = append(parts, "c copy scenario · ←/ESC back to list")
-		if m.hasToolDetail(m.detailJobID) {
-			if m.showToolDetail {
-				parts = append(parts, "t clip tool detail")
+		if m.hasToolOutput(m.detailJobID) {
+			if m.showToolOutput {
+				parts = append(parts, "t hide tool output")
 			} else {
-				parts = append(parts, "t full tool detail")
+				parts = append(parts, "t tool output")
 			}
 		}
 		if m.hasLogs() {