fix(tui): anchor details to stream timeline

ui-tui/src/__tests__/createGatewayEventHandler.test.ts

@@ -82,15 +82,13 @@ describe('createGatewayEventHandler', () => {
       type: 'message.complete'
     } as any)
 
-    expect(appended).toHaveLength(1)
-    expect(appended[0]).toMatchObject({
-      role: 'assistant',
-      text: 'final answer',
-      thinking: 'mapped the page'
-    })
-    expect(appended[0]?.tools).toHaveLength(1)
-    expect(appended[0]?.tools?.[0]).toContain('hero cards')
-    expect(appended[0]?.toolTokens).toBeGreaterThan(0)
+    expect(appended).toHaveLength(3)
+    expect(appended[0]).toMatchObject({ kind: 'trail', role: 'system', text: '', thinking: 'mapped the page' })
+    expect(appended[1]).toMatchObject({ kind: 'trail', role: 'system', text: '' })
+    expect(appended[1]?.tools).toHaveLength(1)
+    expect(appended[1]?.tools?.[0]).toContain('hero cards')
+    expect(appended[1]?.toolTokens).toBeGreaterThan(0)
+    expect(appended[2]).toMatchObject({ role: 'assistant', text: 'final answer' })
   })
 
   it('keeps tool tokens across handler recreation mid-turn', () => {
@@ -118,9 +116,10 @@ describe('createGatewayEventHandler', () => {
       type: 'message.complete'
     } as any)
 
-    expect(appended).toHaveLength(1)
-    expect(appended[0]?.tools).toHaveLength(1)
-    expect(appended[0]?.toolTokens).toBeGreaterThan(0)
+    expect(appended).toHaveLength(3)
+    expect(appended[1]?.tools).toHaveLength(1)
+    expect(appended[1]?.toolTokens).toBeGreaterThan(0)
+    expect(appended[2]).toMatchObject({ role: 'assistant', text: 'final answer' })
   })
 
   it('streams legacy thinking.delta into visible reasoning state', () => {
@@ -148,9 +147,10 @@ describe('createGatewayEventHandler', () => {
     onEvent({ payload: { text: fallback }, type: 'reasoning.available' } as any)
     onEvent({ payload: { text: 'final answer' }, type: 'message.complete' } as any)
 
-    expect(appended).toHaveLength(1)
+    expect(appended).toHaveLength(2)
     expect(appended[0]?.thinking).toBe(streamed)
     expect(appended[0]?.thinkingTokens).toBe(estimateTokensRough(streamed))
+    expect(appended[1]).toMatchObject({ role: 'assistant', text: 'final answer' })
   })
 
   it('uses message.complete reasoning when no streamed reasoning ref', () => {
@@ -161,9 +161,10 @@ describe('createGatewayEventHandler', () => {
 
     onEvent({ payload: { reasoning: fromServer, text: 'final answer' }, type: 'message.complete' } as any)
 
-    expect(appended).toHaveLength(1)
+    expect(appended).toHaveLength(2)
     expect(appended[0]?.thinking).toBe(fromServer)
     expect(appended[0]?.thinkingTokens).toBe(estimateTokensRough(fromServer))
+    expect(appended[1]).toMatchObject({ role: 'assistant', text: 'final answer' })
   })
 
   it('anchors inline_diff as its own segment where the edit happened', () => {
@@ -184,21 +185,19 @@ describe('createGatewayEventHandler', () => {
     expect(appended).toHaveLength(0)
     expect(turnController.segmentMessages).toEqual([
       { role: 'assistant', text: 'Editing the file' },
+      { kind: 'trail', role: 'system', text: '', tools: ['Patch("foo.ts")  ✓'] },
       { kind: 'diff', role: 'assistant', text: block }
     ])
 
     onEvent({ payload: { text: 'patch applied' }, type: 'message.complete' } as any)
 
-    // Four transcript messages: pre-tool narration → tool trail → diff
-    // (kind='diff', so MessageLine gives it blank-line breathing room) →
-    // post-tool narration. The final message does NOT contain a diff.
-    expect(appended).toHaveLength(4)
+    expect(appended).toHaveLength(5)
     expect(appended[0]?.text).toBe('Editing the file')
     expect(appended[1]).toMatchObject({ kind: 'trail' })
     expect(appended[1]?.tools?.[0]).toContain('Patch')
     expect(appended[2]).toMatchObject({ kind: 'diff', text: block })
-    expect(appended[3]?.text).toBe('patch applied')
-    expect(appended[3]?.text).not.toContain('```diff')
+    expect(appended[4]?.text).toBe('patch applied')
+    expect(appended[4]?.text).not.toContain('```diff')
   })
 
   it('drops the diff segment when the final assistant text narrates the same diff', () => {
@@ -212,9 +211,10 @@ describe('createGatewayEventHandler', () => {
 
     // Only the final message — diff-only segment dropped so we don't
     // render two stacked copies of the same patch.
-    expect(appended).toHaveLength(1)
-    expect(appended[0]?.text).toBe(assistantText)
-    expect((appended[0]?.text.match(/```diff/g) ?? []).length).toBe(1)
+    expect(appended).toHaveLength(2)
+    expect(appended[0]).toMatchObject({ kind: 'trail' })
+    expect(appended[1]?.text).toBe(assistantText)
+    expect((appended[1]?.text.match(/```diff/g) ?? []).length).toBe(1)
   })
 
   it('strips the CLI "┊ review diff" header from inline diff segments', () => {
@@ -246,9 +246,10 @@ describe('createGatewayEventHandler', () => {
     } as any)
     onEvent({ payload: { text: assistantText }, type: 'message.complete' } as any)
 
-    expect(appended).toHaveLength(1)
-    expect(appended[0]?.text).toBe(assistantText)
-    expect((appended[0]?.text.match(/```diff/g) ?? []).length).toBe(1)
+    expect(appended).toHaveLength(2)
+    expect(appended[0]).toMatchObject({ kind: 'trail' })
+    expect(appended[1]?.text).toBe(assistantText)
+    expect((appended[1]?.text.match(/```diff/g) ?? []).length).toBe(1)
   })
 
   it('keeps tool trail terse when inline_diff is present', () => {

ui-tui/src/app/createGatewayEventHandler.ts

@@ -379,6 +379,10 @@ export function createGatewayEventHandler(ctx: GatewayEventHandlerContext): (ev:
         const inlineDiffText =
           ev.payload.inline_diff && getUiState().inlineDiffs ? stripAnsi(String(ev.payload.inline_diff)).trim() : ''
 
+        if (inlineDiffText) {
+          turnController.flushStreamingSegment()
+        }
+
         turnController.recordToolComplete(
           ev.payload.tool_id,
           ev.payload.name,
@@ -386,17 +390,10 @@ export function createGatewayEventHandler(ctx: GatewayEventHandlerContext): (ev:
           inlineDiffText ? '' : ev.payload.summary
         )
 
-        if (!inlineDiffText) {
-          return
+        if (inlineDiffText) {
+          turnController.pushInlineDiffSegment(inlineDiffText)
         }
 
-        // Anchor the diff to where the edit happened in the turn — between
-        // the narration that preceded the tool call and whatever the agent
-        // streams afterwards. The previous end-merge put the diff at the
-        // bottom of the final message even when the edit fired mid-turn,
-        // which read as "the agent wrote this after saying that".
-        turnController.pushInlineDiffSegment(inlineDiffText)
-
         return
       }
 

ui-tui/src/app/turnController.ts

@@ -38,11 +38,7 @@ const diffSegmentBody = (msg: Msg): null | string => {
   return m ? m[1]! : null
 }
 
-const insertBeforeFirstDiff = (segments: Msg[], msg: Msg): Msg[] => {
-  const index = segments.findIndex(segment => segment.kind === 'diff')
-
-  return index < 0 ? [...segments, msg] : [...segments.slice(0, index), msg, ...segments.slice(index)]
-}
+const hasDetails = (msg: Msg): boolean => Boolean(msg.thinking || msg.tools?.length || msg.toolTokens)
 
 export interface InterruptDeps {
   appendMessage: (msg: Msg) => void
@@ -69,6 +65,7 @@ class TurnController {
   persistSpawnTree?: (subagents: SubagentProgress[], sessionId: null | string) => Promise<void>
   protocolWarned = false
   reasoningText = ''
+  reasoningSegmentOffset = 0
   segmentMessages: Msg[] = []
   pendingSegmentTools: string[] = []
   statusTimer: Timer = null
@@ -94,6 +91,7 @@ class TurnController {
   clearReasoning() {
     this.reasoningTimer = clear(this.reasoningTimer)
     this.reasoningText = ''
+    this.reasoningSegmentOffset = 0
     this.toolTokenAcc = 0
     patchTurnState({ reasoning: '', reasoningTokens: 0, toolTokens: 0 })
   }
@@ -181,29 +179,33 @@ class TurnController {
 
   flushStreamingSegment() {
     const raw = this.bufRef.trimStart()
-
-    if (!raw) {
-      return
-    }
-
-    const split = hasReasoningTag(raw) ? splitReasoning(raw) : { reasoning: '', text: raw }
+    const split = raw ? (hasReasoningTag(raw) ? splitReasoning(raw) : { reasoning: '', text: raw }) : { reasoning: '', text: '' }
 
     if (split.reasoning && !this.reasoningText.trim()) {
       this.reasoningText = split.reasoning
       patchTurnState({ reasoning: this.reasoningText, reasoningTokens: estimateTokensRough(this.reasoningText) })
     }
 
-    const text = split.text
+    const thinking = this.reasoningText.slice(this.reasoningSegmentOffset).trim()
+    const msg: Msg = {
+      role: split.text ? 'assistant' : 'system',
+      text: split.text,
+      ...(!split.text && { kind: 'trail' as const }),
+      ...(thinking && {
+        thinking,
+        thinkingTokens: estimateTokensRough(thinking)
+      }),
+      ...(this.pendingSegmentTools.length && { tools: this.pendingSegmentTools })
+    }
 
     this.streamTimer = clear(this.streamTimer)
 
-    if (text) {
-      const tools = this.pendingSegmentTools
-
-      this.segmentMessages = [...this.segmentMessages, { role: 'assistant', text, ...(tools.length && { tools }) }]
-      this.pendingSegmentTools = []
+    if (split.text || hasDetails(msg)) {
+      this.segmentMessages = [...this.segmentMessages, msg]
     }
 
+    this.reasoningSegmentOffset = this.reasoningText.length
+    this.pendingSegmentTools = []
     this.bufRef = ''
     patchTurnState({ streamPendingTools: [], streamSegments: this.segmentMessages, streaming: '' })
   }
@@ -295,7 +297,6 @@ class TurnController {
     const finalText = split.text
     const existingReasoning = this.reasoningText.trim() || String(payload.reasoning ?? '').trim()
     const savedReasoning = [existingReasoning, existingReasoning ? '' : split.reasoning].filter(Boolean).join('\n\n')
-    const savedReasoningTokens = savedReasoning ? estimateTokensRough(savedReasoning) : 0
     const savedToolTokens = this.toolTokenAcc
     const tools = this.pendingSegmentTools
 
@@ -312,32 +313,20 @@ class TurnController {
       return body === null || (!finalHasOwnDiffFence && !finalText.includes(body))
     })
 
-    const hasDiffSegment = segments.some(msg => msg.kind === 'diff')
-    const detailsBelongBeforeDiff = hasDiffSegment && (tools.length > 0 || Boolean(savedReasoning))
-
-    const finalMessages = detailsBelongBeforeDiff
-      ? insertBeforeFirstDiff(segments, {
-          kind: 'trail',
-          role: 'system',
-          text: '',
-          thinking: savedReasoning || undefined,
-          thinkingTokens: savedReasoning ? savedReasoningTokens : undefined,
-          toolTokens: savedToolTokens || undefined,
-          ...(tools.length && { tools })
-        })
-      : [...segments]
+    const finalThinking = savedReasoning.slice(this.reasoningSegmentOffset).trim()
+    const finalDetails: Msg = {
+      kind: 'trail',
+      role: 'system',
+      text: '',
+      thinking: finalThinking || undefined,
+      thinkingTokens: finalThinking ? estimateTokensRough(finalThinking) : undefined,
+      toolTokens: savedToolTokens || undefined,
+      ...(tools.length && { tools })
+    }
+    const finalMessages = hasDetails(finalDetails) ? [...segments, finalDetails] : [...segments]
 
     if (finalText) {
-      finalMessages.push({
-        role: 'assistant',
-        text: finalText,
-        ...(!detailsBelongBeforeDiff && {
-          thinking: savedReasoning || undefined,
-          thinkingTokens: savedReasoning ? savedReasoningTokens : undefined,
-          toolTokens: savedToolTokens || undefined,
-          ...(tools.length && { tools })
-        })
-      })
+      finalMessages.push({ role: 'assistant', text: finalText })
     }
 
     const wasInterrupted = this.interrupted