Merge remote-tracking branch 'origin/master' into mergebot/pr965

apps/web/tests/markdown-images.e2e.ts

@@ -0,0 +1,205 @@
+// Web e2e scenario: absolute HTTP(S) Markdown images. A validated session
+// assembled through the Session API is seeded cold into the real web
+// composition, then a separate image origin proves that the browser receives
+// a real network image while local-path Markdown remains inert alt text.
+import { createServer, type Server } from 'node:http'
+import { fileURLToPath } from 'node:url'
+import type { Browser, Page } from 'playwright'
+import { chromium } from 'playwright'
+import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
+import { createMessage, createUserMessage } from '@deepseek-ai/dsh-llm'
+import {
+  SESSION_FORMAT_VERSION,
+  Session,
+  SessionId,
+} from '@deepseek-ai/dsh-session'
+import type {} from '@deepseek-ai/dsh-session-title'
+import {
+  assertFixtureInventory,
+  captureStableAria,
+  compareOrRefreshGolden,
+  launchWebScaffold,
+  seedSession,
+  watchConsole,
+  webSnapshotMode,
+  type WebScaffold,
+} from './scaffold.ts'
+import { newEnglishPage, saveFailureShot } from './support.ts'
+
+const SNAPSHOT_DIR = fileURLToPath(new URL('./snapshots/markdown-images', import.meta.url))
+const UI_EXPECTED = fileURLToPath(new URL('./snapshots/markdown-images/ui.expected.md', import.meta.url))
+const MODE = webSnapshotMode()
+const SEED_ID = 'markdown-images-web-e2e'
+const REMOTE_ALT = 'Remote test image'
+const LOCAL_ALT = 'Local test image'
+const PNG = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=',
+  'base64',
+)
+
+interface ImageOrigin {
+  server: Server
+  url: string
+  requests: Array<{ path: string | undefined; referer: string | undefined }>
+}
+
+/** Start the deterministic remote image origin used by this browser scenario. */
+async function startImageOrigin(): Promise<ImageOrigin> {
+  const requests: ImageOrigin['requests'] = []
+  const server = createServer((request, response) => {
+    requests.push({ path: request.url, referer: request.headers.referer })
+    response.writeHead(200, {
+      'cache-control': 'no-store',
+      'content-length': PNG.length,
+      'content-type': 'image/png',
+    })
+    response.end(PNG)
+  })
+  await new Promise<void>((resolve, reject) => {
+    server.once('error', reject)
+    server.listen(0, '127.0.0.1', resolve)
+  })
+  const address = server.address()
+  if (address === null || typeof address === 'string') {
+    throw new Error('image origin did not expose an IP socket')
+  }
+  return {
+    server,
+    url: `http://127.0.0.1:${String(address.port)}/image.png`,
+    requests,
+  }
+}
+
+/** Stop one image origin after the browser and host release their requests. */
+async function stopServer(server: Server): Promise<void> {
+  await new Promise<void>((resolve, reject) => {
+    server.close((error) => {
+      if (error === undefined) resolve()
+      else reject(error)
+    })
+  })
+}
+
+/** Build one closed, invariant-checked session fixture with remote and local image Markdown. */
+function markdownImageFixture(remoteUrl: string): string {
+  const session = new Session(SessionId('markdown-image-source'))
+  session.append('turn/start', {
+    turn: 1,
+    trigger: { kind: 'message', source: { kind: 'user' } },
+  })
+  const user = session.append('user/message', createUserMessage({
+    content: [{ type: 'text', text: 'Show the Markdown image policy.' }],
+    source: { kind: 'user' },
+  }), { surfaceOp: 'append' })
+  session.append('session/title', {
+    title: 'Markdown image policy',
+    messageSeqs: [user.seq],
+    source: { kind: 'fallback' },
+  })
+  session.append('step/start', { turn: 1, step: 1 })
+  session.append('assistant/message', {
+    turn: 1,
+    step: 1,
+    message: createMessage({
+      role: 'assistant',
+      content: [{
+        type: 'text',
+        text: [
+          '## Markdown images',
+          '',
+          `![${REMOTE_ALT}](${remoteUrl})`,
+          '',
+          `![${LOCAL_ALT}](./local-image.png)`,
+          '',
+          'REMOTE_IMAGE_DONE',
+        ].join('\n'),
+      }],
+      source: { kind: 'model', provider: 'fixture', model: 'fixture' },
+    }),
+  }, { surfaceOp: 'append' })
+  session.append('step/end', { turn: 1, step: 1 })
+  session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
+
+  const header = {
+    type: 'session',
+    version: SESSION_FORMAT_VERSION,
+    id: '{{sessionId}}',
+    createdAt: 0,
+    cwd: '{{cwd}}',
+  }
+  return [
+    JSON.stringify(header),
+    ...session.events.map(event => JSON.stringify(event)),
+    '',
+  ].join('\n')
+}
+
+describe('web e2e: remote Markdown image rendering', () => {
+  let scaffold: WebScaffold
+  let imageOrigin: ImageOrigin
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+
+  beforeAll(async () => {
+    imageOrigin = await startImageOrigin()
+    scaffold = await launchWebScaffold({})
+    await seedSession(scaffold, markdownImageFixture(imageOrigin.url), SEED_ID)
+    browser = await chromium.launch()
+    page = await newEnglishPage(browser)
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+    await stopServer(imageOrigin.server)
+  })
+
+  it.skipIf(MODE === 'record')('loads only the remote image and matches the conversation golden', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-markdown-images'))
+    const groupRow = page.locator('[role="treeitem"]').first()
+    await groupRow.waitFor({ timeout: 15_000 })
+    await groupRow.click()
+    const sessionRow = page.locator('[role="treeitem"]').nth(1)
+    await sessionRow.waitFor({ timeout: 10_000 })
+    await sessionRow.click()
+    await expect.poll(() => page.getByText('REMOTE_IMAGE_DONE', { exact: true }).count(), {
+      timeout: 15_000,
+    }).toBe(1)
+
+    const image = page.getByRole('img', { name: REMOTE_ALT })
+    await image.waitFor({ timeout: 10_000 })
+    await expect.poll(() => image.evaluate(element => (element as HTMLImageElement).naturalWidth), {
+      timeout: 10_000,
+    }).toBeGreaterThan(0)
+    expect(await image.evaluate((element) => {
+      const computed = getComputedStyle(element)
+      return {
+        borderRadius: computed.borderRadius,
+        decoding: element.getAttribute('decoding'),
+        loading: element.getAttribute('loading'),
+        maxWidth: computed.maxWidth,
+        referrerPolicy: element.getAttribute('referrerpolicy'),
+      }
+    })).toEqual({
+      borderRadius: '8px',
+      decoding: 'async',
+      loading: 'lazy',
+      maxWidth: '100%',
+      referrerPolicy: 'no-referrer',
+    })
+    expect(await page.getByRole('img', { name: LOCAL_ALT }).count()).toBe(0)
+    expect(await page.getByText(LOCAL_ALT, { exact: true }).count()).toBe(1)
+    expect(imageOrigin.requests).toEqual([{ path: '/image.png', referer: undefined }])
+
+    const snapshot = (await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd))
+      .split(SEED_ID).join('{{seededId}}')
+    await compareOrRefreshGolden(UI_EXPECTED, snapshot, MODE)
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+    await assertFixtureInventory(SNAPSHOT_DIR, ['ui.expected.md'])
+  }, 60_000)
+})

apps/web/tests/message-actions.e2e.ts

@@ -1,7 +1,7 @@
-// Web e2e scenario: message IconActions + clocks. Cold-seeds the seeded-history
-// fixture (zero model calls) and pins the settled conversation aria after the
-// user/assistant footers are focus-revealed — the surface package jsdom tests
-// cannot substitute for (docs/testing.md snapshot rule).
+// Web e2e scenario: message IconActions + clocks. Cold-seeds a deterministic
+// completed-turn-tail fork case (zero model calls) and pins the settled
+// conversation aria after the footers are focus-revealed — the surface package
+// jsdom tests cannot substitute for (docs/testing.md snapshot rule).
 import { mkdir, readFile, writeFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import { fileURLToPath } from 'node:url'
@@ -25,6 +25,48 @@ const MODE = webSnapshotMode()
 const SEED_ID = 'message-actions-web-e2e'
 
 const PROMPT = 'Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop.'
+const MID_TURN_TEXT = 'I will read both files before answering.'
+const SECOND_PROMPT = 'Now give the final answer.'
+
+/**
+ * Adapt the borrowed recording into response -> tools -> interrupted Think,
+ * followed by one ordinary completed response. The first response keeps
+ * copy/clock but is not a legal branch point; the second is the real turn tail.
+ * @param raw - Recorded seeded-history JSONL.
+ * @returns A contiguous, closed two-turn fixture.
+ */
+function completedTailFixture(raw: string): string {
+  const kept: string[] = []
+  for (const line of raw.trimEnd().split('\n')) {
+    const row = JSON.parse(line) as {
+      type: string
+      seq?: number
+      seq0?: number
+      data?: { content?: unknown[] }
+    }
+    const firstSeq = row.seq ?? row.seq0
+    if (firstSeq !== undefined && firstSeq >= 101) break
+    if (row.type === 'assistant/message' && row.seq === 64) {
+      const content = row.data?.content
+      if (!Array.isArray(content)) throw new Error('borrowed step-one assistant message has no content')
+      content.splice(1, 0, { type: 'text', text: MID_TURN_TEXT })
+      kept.push(JSON.stringify(row))
+    } else {
+      kept.push(line)
+    }
+  }
+  const tail = [
+    { type: 'step/end', seq: 101, time: 1784974102749, data: { turn: 1, step: 2 } },
+    { type: 'turn/end', seq: 102, time: 1784974102750, data: { turn: 1, reason: { kind: 'aborted' } } },
+    { type: 'turn/start', seq: 103, time: 1784974103000, data: { turn: 2, trigger: { kind: 'message', source: { kind: 'user', rpcId: '{{rpcId}}' } } } },
+    { type: 'user/message', seq: 104, time: 1784974103001, data: { content: [{ type: 'text', text: SECOND_PROMPT }], source: { kind: 'user', rpcId: '{{rpcId}}' } }, surfaceOp: 'append' },
+    { type: 'step/start', seq: 105, time: 1784974103002, data: { turn: 2, step: 1 } },
+    { type: 'assistant/message', seq: 106, time: 1784974103003, data: { turn: 2, step: 1, content: [{ type: 'text', text: 'DONE' }], provenance: { provider: 'deepseek-official', model: 'deepseek-v4-flash' } }, sourceEventSeqs: [], surfaceOp: 'append' },
+    { type: 'step/end', seq: 107, time: 1784974103004, data: { turn: 2, step: 1 } },
+    { type: 'turn/end', seq: 108, time: 1784974103005, data: { turn: 2, reason: { kind: 'completed' } } },
+  ]
+  return `${[...kept, ...tail.map(row => JSON.stringify(row))].join('\n')}\n`
+}
 
 describe('web e2e: message IconActions and clocks on settled history', () => {
   let scaffold: WebScaffold
@@ -38,8 +80,8 @@ describe('web e2e: message IconActions and clocks on settled history', () => {
     await mkdir(sessionCwd, { recursive: true })
     await writeFile(join(sessionCwd, 'a.txt'), 'alpha\n')
     await writeFile(join(sessionCwd, 'b.txt'), 'beta\n')
-    const raw = await readFile(SEED, 'utf8')
-    expect(fixtureUserPrompts(raw), 'borrowed seed must carry the drive prompt').toEqual([PROMPT])
+    const raw = completedTailFixture(await readFile(SEED, 'utf8'))
+    expect(fixtureUserPrompts(raw), 'adapted seed must carry both prompts').toEqual([PROMPT, SECOND_PROMPT])
     await seedSession(scaffold, raw, SEED_ID)
     browser = await chromium.launch()
     page = await newEnglishPage(browser)
@@ -53,7 +95,7 @@ describe('web e2e: message IconActions and clocks on settled history', () => {
     await scaffold?.close()
   })
 
-  it.skipIf(MODE === 'record')('lists the seeded session and reveals user/assistant IconActions', async () => {
+  it.skipIf(MODE === 'record')('enables branch only on the completed transcript tail', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-message-actions'))
     const groupRow = page.locator('[role="treeitem"]').first()
     await groupRow.waitFor({ timeout: 15_000 })
@@ -61,16 +103,24 @@ describe('web e2e: message IconActions and clocks on settled history', () => {
     const sessionRow = page.locator('[role="treeitem"]').nth(1)
     await sessionRow.waitFor({ timeout: 10_000 })
     await sessionRow.click()
+    await expect.poll(() => page.getByText(MID_TURN_TEXT, { exact: true }).count(), { timeout: 15_000 }).toBe(1)
     await expect.poll(() => page.getByText('DONE', { exact: true }).count(), { timeout: 15_000 }).toBe(1)
 
     // Focus-reveal the footers (hover:hover keeps them opacity-hidden until
-    // hover/focus-within). User and each turn's last content assistant both
-    // have copy + branch.
+    // hover/focus-within). Every durable message footer keeps branch visible,
+    // but only the final assistant at a completed transcript tail enables it.
     const copyButtons = page.getByRole('button', { name: 'Copy' })
-    await expect.poll(() => copyButtons.count(), { timeout: 10_000 }).toBeGreaterThanOrEqual(2)
+    await expect.poll(() => copyButtons.count(), { timeout: 10_000 }).toBeGreaterThanOrEqual(4)
     await copyButtons.first().focus()
-    await expect.poll(() => page.getByRole('button', { name: 'Branch into a new conversation' }).count(), { timeout: 5_000 })
-      .toBeGreaterThanOrEqual(2)
+    const branchButtons = page.getByRole('button', { name: 'Branch into a new conversation' })
+    await expect.poll(() => branchButtons.count(), { timeout: 5_000 }).toBe(4)
+    await expect.poll(
+      () => branchButtons.evaluateAll(buttons => buttons.map(button => button.getAttribute('aria-disabled'))),
+      { timeout: 5_000 },
+    ).toEqual(['true', 'true', 'true', null])
+    await branchButtons.first().focus()
+    await expect.poll(() => page.getByRole('tooltip').textContent(), { timeout: 5_000 })
+      .toBe('Available only on the last message of a completed turn')
     await expect.poll(() => page.getByRole('button', { name: 'Edit' }).count(), { timeout: 5_000 }).toBe(0)
   }, 60_000)
 
@@ -89,8 +139,7 @@ describe('web e2e: message IconActions and clocks on settled history', () => {
 
   it.skipIf(MODE === 'record')('forks through the settled-message and session-row actions', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-message-fork'))
-    // Exercise the assistant action specifically; package coverage pins the
-    // user action separately at its own event seq.
+    // The last message action belongs to the completed second-turn assistant.
     await page.getByRole('button', { name: 'Branch into a new conversation' }).last().click()
     await expect.poll(
       () => scaffold.ctx.agents.list().find(agent => agent.session.header.parentSession === SessionId(SEED_ID)),

apps/web/tests/snapshots/bash-abort-row/ui.expected.md

@@ -7,8 +7,9 @@
 - text: "Run two shell commands: wait for cancellation, then write skipped.txt. {{date}} {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/code-mode-round/ui.expected.md

@@ -7,8 +7,9 @@
 - text: "Using ONE run_code program: run bash `echo CODE_ROUND_OK`, then read the file missing.txt catching its error in the program. Return an object with both outcomes. Then reply DONE and stop. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/cordis-tool-round/ui.expected.md

@@ -7,8 +7,9 @@
 - text: "Use only Cordis tools. First call cordis_inspect with what \"temporary\". Then call cordis_mount with this exact code: \"return { name: \\\"snapshot-noop\\\", apply(ctx) {} }\". Read its returned id and call cordis_unmount with that exact id. After all three calls succeed, reply exactly CORDIS_UI_DONE and stop. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/fresh-round-trip/ui.expected.md

@@ -7,8 +7,9 @@
 - text: "Use the bash tool to run exactly: echo WEB_E2E_OK. Then reply with the single word DONE and stop. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/lifecycle-chrome/reloaded.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with the single word LIGHTHOUSE and stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/live-interactions/cancel.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/live-interactions/error-auth.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/live-interactions/loading.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/live-interactions/retry.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/markdown-images/ui.expected.md

@@ -0,0 +1,30 @@
+- banner:
+  - navigation "Session hierarchy":
+    - button "Markdown image policy" [disabled]
+  - tablist:
+    - tab "Chat" [selected]
+    - tab "Trajectory"
+- text: Show the Markdown image policy. {{clock}}
+- button "Copy":
+  - img
+- button "Branch into a new conversation":
+  - img
+- heading "Markdown images" [level=2]
+- paragraph:
+  - img "Remote test image"
+- paragraph: Local test image
+- paragraph: REMOTE_IMAGE_DONE
+- button "Copy":
+  - img
+- button "Branch into a new conversation":
+  - img
+- text: {{clock}}
+- textbox "Message the agent"
+- button "Commands":
+  - img
+- 'button "Access mode, current: Workspace Write"': Workspace Write
+- button "Select model, current deepseek-v4-flash":
+  - text: deepseek-v4-flash
+  - img
+- button "Send message" [disabled]
+- text: 1 turns · 1 steps Input 0 tok · Output 0 tok

apps/web/tests/snapshots/message-actions/ui.expected.md

@@ -8,12 +8,19 @@
 - button "Copy":
   - img
 - tooltip "Copy"
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Think The user wants me to read a.txt and b.txt, then reply with \"DONE\". Let me do both reads in parallel.":
   - img
   - img
   - text: Think The user wants me to read a.txt and b.txt, then reply with "DONE". Let me do both reads in parallel.
+- paragraph: I will read both files before answering.
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn 7/25 {{clock}}
 - button "Read a.txt":
   - img
   - img
@@ -28,6 +35,12 @@
   - img
   - img
   - text: Think Both files have been read. a.txt contains "alpha" and b.txt contains "beta". I'll now reply with DONE as instructed.
+- text: Stopped Now give the final answer. 7/25 {{clock}}
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn
 - paragraph: DONE
 - button "Copy":
   - img
@@ -42,4 +55,4 @@
   - text: deepseek-v4-flash
   - img
 - button "Send message" [disabled]
-- text: 1 turns · 2 steps Tool call {{duration}} Cache hit 98% Input 15.8K tok · Output 135 tok
+- text: 2 turns · 3 steps Tool call {{duration}} Cache hit 98% Input 7.8K tok · Output 103 tok

apps/web/tests/snapshots/plan-review/approved.expected.md

@@ -8,8 +8,9 @@
 - text: "plan Plan mode on. Use /plan off to leave. Plan a small change: add a --greeting flag to a CLI. Do not read or write any files. Call exit_plan_mode with a short plan of at most five bullet points. Once the plan is approved, reply with the single word DONE and stop. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/question-composer/answered.expected.md

@@ -7,8 +7,9 @@
 - text: "Use the ask_user_question tool to ask me exactly one question with id \"color\", question \"Which color do you prefer?\", header \"Pick one\", and two options: label \"Blue\" with description \"A cool recessive hue that reads as calm and trustworthy in long reading sessions and dense dashboards.\", and label \"Green\" with description \"A restful mid-spectrum hue with the highest perceived brightness, easiest on the eye over long sessions.\" After I answer, reply with the single word DONE and stop. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/queue-actions/collapsed.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/queue-actions/editing.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/queue-actions/preserved.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img
@@ -22,8 +23,9 @@
 - text: {{clock}} Edited queue item {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - paragraph: partial
 - status: Deep diving...
 - list:

apps/web/tests/snapshots/queue-actions/ui.expected.md

@@ -7,8 +7,9 @@
 - text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/seeded-history/command-row.expected.md

@@ -7,8 +7,9 @@
 - text: "Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop. 7/25 {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Think The user wants me to read a.txt and b.txt, then reply with \"DONE\". Let me do both reads in parallel.":
   - img
   - img

apps/web/tests/snapshots/seeded-history/ui.expected.md

@@ -7,8 +7,9 @@
 - text: "Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop. 7/25 {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Think The user wants me to read a.txt and b.txt, then reply with \"DONE\". Let me do both reads in parallel.":
   - img
   - img

apps/web/tests/snapshots/steering/mid-steer.expected.md

@@ -7,8 +7,9 @@
 - text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img

apps/web/tests/snapshots/steering/settled.expected.md

@@ -7,8 +7,9 @@
 - text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img
@@ -24,8 +25,9 @@
 - text: "Interjection: include the word BANANA in your final reply. {{clock}}"
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Think The user selected \"Yes\" and wants me to include the word \"BANANA\" in my final reply. Let me acknowledge their answer.":
   - img
   - img

apps/web/tests/snapshots/subagent-conversation/ui.expected.md

@@ -12,8 +12,9 @@
 - text: Explain event sourcing in one sentence. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img
@@ -30,8 +31,9 @@
 - text: {{clock}} Now give the same explanation to a human reader. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Think The user is asking for a one-sentence description of event sourcing. This is a straightforward knowledge question that doesn't require any skill loading or tool calls.":
   - img
   - img

apps/web/tests/snapshots/web-search-round/ui.expected.md

@@ -7,8 +7,9 @@
 - text: Use web_search to search exactly "DeepSeek Harness snapshot search". Then reply exactly SEARCH_DONE and stop. {{clock}}
 - button "Copy":
   - img
-- button "Branch into a new conversation":
+- button "Branch into a new conversation" [disabled]:
   - img
+- text: Available only on the last message of a completed turn
 - button "Context injection":
   - img
   - img