Merge remote-tracking branch 'origin/master' into codex/session-scoped-sandbox-roots

# Conflicts:
#	.agents/notes/implemented/feature/2026-07-14-cross-family-fs-sandbox.i18n.yaml
#	.agents/notes/implemented/feature/2026-07-14-cross-family-fs-sandbox.md
#	.agents/notes/implemented/feature/2026-07-14-cross-family-fs-sandbox.zh.md
#	examples/acp-agent/README.md
#	packages/examples/agent-spine-demo/package.json
#	packages/fs/fs-sandbox/src/index.ts
#	packages/fs/tool-fs-search/tests/tools.spec.ts
#	packages/support/acp-snapshot/README.md
#	packages/support/acp-snapshot/src/suite.ts
#	pnpm-lock.yaml
#	scripts/type-equiv.manifest.json

packages/support/acp-snapshot/src/harness.ts

@@ -24,6 +24,8 @@ import { basename, dirname, join, delimiter } from 'node:path'
 import {
   ClientSideConnection,
   PROTOCOL_VERSION,
+  type CreateElicitationRequest,
+  type CreateElicitationResponse,
   type RequestPermissionRequest,
   type RequestPermissionResponse,
   type SessionNotification,
@@ -59,6 +61,8 @@ export type InputStep =
     waitForToolCallUpdate?: string
   }
   | { op: 'cancel' }
+  | { op: 'setMode'; modeId: string }
+  | { op: 'setModeExpectError'; modeId: string }
   | { op: 'setConfigOption'; configId: string; value: string }
   | { op: 'setConfigOptionExpectError'; configId: string; value: string }
 
@@ -78,6 +82,16 @@ export interface InputScript {
    * agent itself just sees `cancelled`, so it cannot absorb the bug).
    */
   permissionAnswers?: PermissionAnswer[]
+  /**
+   * Ordered answers for the agent's `elicitation/create` round-trips (the
+   * ask_user_question / plan-review forms), consumed FIFO — the Nth request
+   * gets the Nth answer. Exhaustion (or no queue) answers `cancel`, the same
+   * fail-closed stub an elicitation-free scenario relies on. Unlike permission
+   * kinds, the scripted strings are not validated against the offered form —
+   * a stray `choice` reaches the agent verbatim, which reads it as a custom
+   * (non-consenting) answer, so a scenario bug fails safe in the transcript.
+   */
+  elicitationAnswers?: ElicitationAnswer[]
 }
 
 /** One scripted answer to a permission request: which offered option kind to select. */
@@ -86,6 +100,16 @@ export interface PermissionAnswer {
   kind: 'allow_once' | 'allow_always' | 'reject_once' | 'reject_always'
 }
 
+/** One scripted answer to an elicitation form (accept with choice/custom content, or cancel). */
+export interface ElicitationAnswer {
+  /** Accept the form with the content below, or cancel it. */
+  action: 'accept' | 'cancel'
+  /** The selected option label (the form's `choice` field). */
+  choice?: string
+  /** Free-form text (the form's `custom` field). */
+  custom?: string
+}
+
 /** One harvested session log plus the identifying facts off its header line. */
 export interface HarvestedLog {
   /** The recorded session id (header `id`). */
@@ -161,11 +185,21 @@ export interface RunOptions {
   configPath?: string
 }
 
-/** Derive one stable, fixed-length spill root owned by this scenario. */
-function scenarioSpillRoot(fixtureFile: string): string {
+/**
+ * Derive one stable, fixed-length spill root owned by this scenario.
+ * Windows uses a two-character-shorter root because drive resolution adds its drive prefix.
+ * @param fixtureFile - The scenario fixture whose parent directory provides the stable identity.
+ * @param platform - the host platform, injectable for unit coverage.
+ * @returns the root-relative snapshot spill directory.
+ */
+export function snapshotSpillRoot(
+  fixtureFile: string,
+  platform: NodeJS.Platform = process.platform,
+): string {
   const scenario = basename(dirname(fixtureFile))
   const key = createHash('sha256').update(scenario).digest('hex').slice(0, 9)
-  return `/tmp/dsh-acp-snap-${key}`
+  const root = platform === 'win32' ? '/t' : '/tmp'
+  return `${root}/dsh-acp-snap-${key}`
 }
 
 /**
@@ -184,7 +218,7 @@ export async function runScenario(input: InputScript, opts: RunOptions): Promise
   // before stdout normalization, so tmpdir() length differences churn expected outputs.
   // Scenario ownership also matters: replay runs concurrently, and one teardown
   // must never delete another scenario's in-flight full-output recovery file.
-  const spillRoot = scenarioSpillRoot(opts.fixtureFile)
+  const spillRoot = snapshotSpillRoot(opts.fixtureFile)
   // Everything past the temp-dir creation is followed by failure-safe cleanup,
   // so a failure in workspace seeding, spawn, or any step never leaks resources.
   let launched: LaunchedAcpTestAgent | undefined
@@ -213,6 +247,8 @@ export async function runScenario(input: InputScript, opts: RunOptions): Promise
     // Permission answers are consumed FIFO across the whole run; exhaustion
     // falls back to `cancelled` so approval-free scenarios keep the plain stub.
     const permissionQueue = [...input.permissionAnswers ?? []]
+    // Elicitation answers mirror the permission queue: FIFO, cancel on exhaustion.
+    const elicitationQueue = [...input.elicitationAnswers ?? []]
     // A scenario bug detected inside a client callback (a scripted permission
     // kind the agent never offered). It cannot fail the run from in there: a
     // callback throw only becomes a JSON-RPC error RESPONSE to the agent, and
@@ -242,6 +278,17 @@ export async function runScenario(input: InputScript, opts: RunOptions): Promise
         }
         return Promise.resolve({ outcome: { outcome: 'selected', optionId: option.optionId } })
       },
+      createElicitation(_params: CreateElicitationRequest): Promise<CreateElicitationResponse> {
+        const answer = elicitationQueue.shift()
+        if (answer === undefined || answer.action !== 'accept') return Promise.resolve({ action: 'cancel' })
+        return Promise.resolve({
+          action: 'accept',
+          content: {
+            ...answer.choice !== undefined ? { choice: answer.choice } : {},
+            ...answer.custom !== undefined ? { custom: answer.custom } : {},
+          },
+        })
+      },
     })
     const active = launched
     await active.spawned
@@ -397,6 +444,24 @@ async function runStep(
       await client.cancel({ sessionId })
       return
     }
+    case 'setMode': {
+      const sessionId = getSessionId()
+      if (sessionId === undefined) throw new Error('snapshot-harness: setMode before newSession')
+      await client.setSessionMode({ sessionId, modeId: step.modeId })
+      return
+    }
+    case 'setModeExpectError': {
+      const sessionId = getSessionId()
+      if (sessionId === undefined) throw new Error('snapshot-harness: setModeExpectError before newSession')
+      // The bridge rejects an unknown/uncomposed mode id with invalidParams;
+      // that rejection IS the expected wire behavior — swallow it so the run
+      // completes and the error frame is captured in the transcript.
+      await client.setSessionMode({ sessionId, modeId: step.modeId }).then(
+        () => { throw new Error('snapshot-harness: expected session/set_mode to be rejected but it succeeded') },
+        () => { /* expected: the bridge rejected the mode id */ },
+      )
+      return
+    }
     case 'setConfigOption': {
       const sessionId = getSessionId()
       if (sessionId === undefined) throw new Error('snapshot-harness: setConfigOption before newSession')

packages/support/acp-snapshot/src/index.ts

@@ -18,6 +18,7 @@
 
 export {
   runScenario,
+  type ElicitationAnswer,
   type HarvestedLog,
   type InputScript,
   type InputStep,
@@ -37,10 +38,14 @@ export {
   scrubRequestHeaders,
   scrubSystemPrompts,
   scrubToolSchemas,
+  type CwdPathMode,
   type NormalizeContext,
+  type NormalizeOptions,
 } from './normalize.ts'
 export {
   defineAcpSnapshotSuite,
+  refreshFixtureReplacements,
+  stabilizeRefreshLog,
   type Scenario,
   type SnapshotSuiteOptions,
 } from './suite.ts'

packages/support/acp-snapshot/src/launcher.ts

@@ -15,12 +15,16 @@ import {
   ndJsonStream,
   type Agent as AcpAgent,
   type Client,
+  type CreateElicitationRequest,
+  type CreateElicitationResponse,
   type RequestPermissionRequest,
   type RequestPermissionResponse,
   type SessionNotification,
 } from '@agentclientprotocol/sdk'
 import { resolveExampleLaunch } from '@deepseek-ai/dsh-loader-smoke'
 
+const EXIT_MARKER_GRACE_MS = 250
+
 /** The source/built agent entry, leaf config, and workspace tsconfig an ACP test boots. */
 export interface AgentUnderTest {
   /** The agent source bin entry (for example `packages/examples/acp-demo/src/bin.ts`). */
@@ -45,6 +49,8 @@ export interface AcpTestLaunchOptions {
   env?: NodeJS.ProcessEnv
   /** Permission handler; omitted requests fail closed as `cancelled`. */
   requestPermission?: (params: RequestPermissionRequest) => Promise<RequestPermissionResponse>
+  /** Elicitation handler; omitted requests fail closed as `cancel`. */
+  createElicitation?: (params: CreateElicitationRequest) => Promise<CreateElicitationResponse>
 }
 
 /** A running ACP test process and its captured client-side surfaces. */
@@ -150,6 +156,8 @@ export function launchAcpTestAgent(options: AcpTestLaunchOptions): LaunchedAcpTe
   }
   const requestPermission = options.requestPermission
     ?? (() => Promise.resolve({ outcome: { outcome: 'cancelled' as const } }))
+  const createElicitation = options.createElicitation
+    ?? (() => Promise.resolve({ action: 'cancel' as const }))
   const makeClient = (_agent: AcpAgent): Client => ({
     sessionUpdate(params: SessionNotification): Promise<void> {
       return trackClientCallback(() => {
@@ -173,6 +181,7 @@ export function launchAcpTestAgent(options: AcpTestLaunchOptions): LaunchedAcpTe
       })
     },
     requestPermission: params => trackClientCallback(() => requestPermission(params)),
+    unstable_createElicitation: params => trackClientCallback(() => createElicitation(params)),
   })
   const client = new ClientSideConnection(makeClient, stream)
   // `exit` only reports the parent process's status. Descendants may retain
@@ -231,6 +240,15 @@ export function launchAcpTestAgent(options: AcpTestLaunchOptions): LaunchedAcpTe
         return
       }
 
+      const propagateFailureAfterDrain = async (): Promise<never> => {
+        await drained
+        closeUpdateStream()
+        throw failure
+      }
+      // Windows implements the supported signal names as forced termination. The exit markers
+      // may therefore arrive after the error wins the race above but before fallback begins.
+      if (!isRunning(child) || await exitMarkerWithinGrace(exited)) return propagateFailureAfterDrain()
+
       // An `error` after spawn is not an exit edge: in particular, a failed
       // signal can leave the subprocess live. Force termination, await the
       // already-observed exit edge, and only then propagate the child error so
@@ -240,6 +258,10 @@ export function launchAcpTestAgent(options: AcpTestLaunchOptions): LaunchedAcpTe
       child.once('error', observeFallbackError)
       if (!child.kill('SIGKILL')) {
         child.off('error', observeFallbackError)
+        // A successful earlier signal may win between the live check and this fallback call.
+        // In that case `kill()` correctly reports no process to signal; the original child error
+        // remains the shutdown result once inherited stdio and callbacks have drained.
+        if (!isRunning(child) || await exitMarkerWithinGrace(exited)) return propagateFailureAfterDrain()
         closeUpdateStream()
         throw new AggregateError(
           [failure, new Error('Fallback SIGKILL was not accepted by the child process')],
@@ -258,9 +280,7 @@ export function launchAcpTestAgent(options: AcpTestLaunchOptions): LaunchedAcpTe
           'ACP test agent failed and fallback termination was refused',
         )
       }
-      await drained
-      closeUpdateStream()
-      throw failure
+      return propagateFailureAfterDrain()
     },
   }
 }
@@ -270,6 +290,17 @@ function waitForExit(child: ChildProcessWithoutNullStreams): Promise<void> {
   return new Promise<void>(resolve => child.once('exit', () => { resolve() }))
 }
 
+/** Give an accepted Windows termination request a bounded window to publish its exit marker. */
+function exitMarkerWithinGrace(exited: Promise<void>): Promise<boolean> {
+  return Promise.race([
+    exited.then(() => true),
+    new Promise<false>((resolve) => {
+      const timer = setTimeout(() => { resolve(false) }, EXIT_MARKER_GRACE_MS)
+      timer.unref()
+    }),
+  ])
+}
+
 /** Whether the child still lacks either OS termination marker. */
 function isRunning(child: ChildProcessWithoutNullStreams): boolean {
   return child.exitCode === null && child.signalCode === null

packages/support/acp-snapshot/src/normalize.ts

@@ -11,20 +11,35 @@ const CWD = '{{cwd}}'
 const SYSTEM = '{{system}}'
 const TOOLS = '{{tools}}'
 const MESSAGE_PREFIX = '{{messagePrefix}}'
+const UPDATED_AT = '{{updatedAt}}'
+
+/** A cwd-rooted path after volatile cwd replacement, through its last separator-delimited segment. */
+const CWD_ROOTED_PATH_RE = /\{\{cwd\}\}(?:[\\/][^\s<>"'`]+)+/g
+const PATH_TAG_RE = /(<path>)([^<]*)(<\/path>)/g
+const ADDITIONAL_INSTRUCTIONS_PATH_RE = /(Additional instructions from: )([^\r\n]+)/g
 
 /** A UUID v4 string, the shape `randomUUID()` produces for session ids. */
 const UUID_RE = /[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/gi
 const LOCAL_SPILL_PATH_RE = new RegExp(
-  String.raw`\{\{cwd\}\}/\.spill/session-[0-9a-f]{12}/[0-9a-f]{12}-([A-Za-z0-9._~-]+?)`
+  String.raw`\{\{cwd\}\}[\\/]\.spill[\\/]session-[0-9a-f]{12}[\\/][0-9a-f]{12}-([A-Za-z0-9._~-]+?)`
   + String.raw`(?=\. Use read with offset/limit|[\s)]|$)`,
   'g',
 )
 const SNAPSHOT_SPILL_PATH_RE = new RegExp(
-  String.raw`/tmp/(?:dsh-acp-snap-[0-9a-f]{9}|dsh-acp-snapshot-spill)/session-[0-9a-f]{12}/[0-9a-f]{12}-([A-Za-z0-9._~-]+?)`
+  String.raw`(?:[A-Za-z]:)?[\\/](?:tmp|t)[\\/](?:dsh-acp-snap-[0-9a-f]{9}|dsh-acp-snapshot-spill)[\\/]session-[0-9a-f]{12}[\\/][0-9a-f]{12}-([A-Za-z0-9._~-]+?)`
   + String.raw`(?=\. Use read with offset/limit|[\s)]|$)`,
   'g',
 )
 
+/** Convert separators only inside generated path-bearing text markers. */
+function canonicalizeEmbeddedPaths(value: string): string {
+  return value
+    .replace(PATH_TAG_RE, (_match, open: string, path: string, close: string) =>
+      `${open}${path.replaceAll('\\', '/')}${close}`)
+    .replace(ADDITIONAL_INSTRUCTIONS_PATH_RE, (_match, prefix: string, path: string) =>
+      `${prefix}${path.replaceAll('\\', '/')}`)
+}
+
 /** Inputs the normalizers need to recognize a run's volatile values. */
 export interface NormalizeContext {
   /** The session id(s) the run issued — replaced with `{{sessionId}}`. */
@@ -33,13 +48,28 @@ export interface NormalizeContext {
   cwd: string
 }
 
+/** How cwd-rooted path separators are represented after the cwd is tokenized. */
+export type CwdPathMode = 'canonical' | 'native'
+
+/** Optional controls shared by stdout and session-log normalization. */
+export interface NormalizeOptions {
+  /** Use `/` for shared goldens, or preserve captured separators for a platform-specific golden. */
+  cwdPathMode?: CwdPathMode
+}
+
 /** Replace cwd, session ids, and any stray UUID with stable tokens in a string. */
-function scrubString(value: string, ctx: NormalizeContext): string {
+function scrubString(value: string, ctx: NormalizeContext, cwdPathMode: CwdPathMode): string {
   let out = value
   // cwd first (longest, most specific), then explicit session ids, then any
   // residual UUID (covers ids that appear in places we didn't enumerate).
   out = out.split(ctx.cwd).join(CWD)
   out = out.split(`/private${CWD}`).join(CWD)
+  if (cwdPathMode === 'canonical') {
+    // Restrict separator conversion to paths rooted at the cwd token. A global
+    // backslash rewrite would corrupt regexes, commands, and model-authored text.
+    out = out.replace(CWD_ROOTED_PATH_RE, path => path.replaceAll('\\', '/'))
+    out = canonicalizeEmbeddedPaths(out)
+  }
   out = out.replace(LOCAL_SPILL_PATH_RE, (_match, name: string) => `{{spillLocator:${name}}}`)
   out = out.replace(SNAPSHOT_SPILL_PATH_RE, (_match, name: string) => `{{spillLocator:${name}}}`)
   for (const id of ctx.sessionIds) out = out.split(id).join(SESSION_ID)
@@ -48,12 +78,15 @@ function scrubString(value: string, ctx: NormalizeContext): string {
 }
 
 /** Recursively scrub a parsed JSON value (strings replaced; structure kept). */
-function scrubValue(value: unknown, ctx: NormalizeContext): unknown {
-  if (typeof value === 'string') return scrubString(value, ctx)
-  if (Array.isArray(value)) return value.map(v => scrubValue(v, ctx))
+function scrubValue(value: unknown, ctx: NormalizeContext, cwdPathMode: CwdPathMode, key?: string): unknown {
+  if (typeof value === 'string') {
+    const scrubbed = scrubString(value, ctx, cwdPathMode)
+    return cwdPathMode === 'canonical' && key === 'path' ? scrubbed.replaceAll('\\', '/') : scrubbed
+  }
+  if (Array.isArray(value)) return value.map(v => scrubValue(v, ctx, cwdPathMode))
   if (value !== null && typeof value === 'object') {
     const out: Record<string, unknown> = {}
-    for (const [k, v] of Object.entries(value)) out[k] = scrubValue(v, ctx)
+    for (const [k, v] of Object.entries(value)) out[k] = scrubValue(v, ctx, cwdPathMode, k)
     return out
   }
   return value
@@ -67,9 +100,15 @@ function scrubValue(value: unknown, ctx: NormalizeContext): unknown {
  *
  * @param rawStdout The captured stdout bytes, decoded utf8.
  * @param ctx The run's volatile values to scrub.
+ * @param options Separator output controls; shared canonical paths are the default.
  * @returns The normalized NDJSON transcript, one frame per line.
  */
-export function normalizeStdout(rawStdout: string, ctx: NormalizeContext): string {
+export function normalizeStdout(
+  rawStdout: string,
+  ctx: NormalizeContext,
+  options: NormalizeOptions = {},
+): string {
+  const cwdPathMode = options.cwdPathMode ?? 'canonical'
   const lines = rawStdout.split('\n').filter(line => line.trim().length > 0)
   // Map each distinct JSON-RPC id (request/response correlate by id) to a stable
   // sequence number, in first-seen order, so id churn doesn't perturb the expected output.
@@ -85,7 +124,9 @@ export function normalizeStdout(rawStdout: string, ctx: NormalizeContext): strin
     if ('id' in frame && frame.id !== undefined && frame.id !== null) {
       frame.id = stableId(frame.id)
     }
-    return scrubValue(frame, ctx) as Record<string, unknown>
+    const update = (frame.params as { update?: Record<string, unknown> } | undefined)?.update
+    if (update?.sessionUpdate === 'session_info_update') update.updatedAt = UPDATED_AT
+    return scrubValue(frame, ctx, cwdPathMode) as Record<string, unknown>
   })
   return frames.map(f => JSON.stringify(f)).join('\n') + '\n'
 }
@@ -99,9 +140,15 @@ export function normalizeStdout(rawStdout: string, ctx: NormalizeContext): strin
  *
  * @param rawLog The raw session `.jsonl` content.
  * @param ctx The run's volatile values to scrub.
+ * @param options Separator output controls; shared canonical paths are the default.
  * @returns The normalized JSONL log, one record per line.
  */
-export function normalizeSessionLog(rawLog: string, ctx: NormalizeContext): string {
+export function normalizeSessionLog(
+  rawLog: string,
+  ctx: NormalizeContext,
+  options: NormalizeOptions = {},
+): string {
+  const cwdPathMode = options.cwdPathMode ?? 'canonical'
   const lines = rawLog.split('\n').filter(line => line.trim().length > 0)
   const records = lines.map((line) => {
     const record = JSON.parse(line) as Record<string, unknown>
@@ -119,7 +166,7 @@ export function normalizeSessionLog(rawLog: string, ctx: NormalizeContext): stri
         if ('durationMs' in data) data.durationMs = 0
       }
     }
-    return scrubValue(record, ctx) as Record<string, unknown>
+    return scrubValue(record, ctx, cwdPathMode) as Record<string, unknown>
   })
   return records.map(r => JSON.stringify(r)).join('\n') + '\n'
 }

packages/support/acp-snapshot/src/suite.ts

@@ -21,6 +21,7 @@ import { join } from 'node:path'
 import { describe, expect, it } from 'vitest'
 import { type AgentUnderTest, type HarvestedLog, type InputScript, runScenario } from './harness.ts'
 import {
+  type CwdPathMode,
   type NormalizeContext,
   normalizeSessionLog,
   normalizeStdout,
@@ -35,6 +36,9 @@ const SYSTEM_PROMPT_SNAPSHOT = 'system-prompt.expected.md'
 /** The structured tool-schema snapshot beside each header-pinning fixture. */
 const TOOL_SCHEMAS_SNAPSHOT = 'tool-schemas.expected.json'
 
+/** The optional full Windows-native stdout transcript. */
+const WINDOWS_STDOUT_SNAPSHOT = 'stdout.expected.windows.jsonl'
+
 /** Stable session-log token standing in for the sidecar's initial schemas. */
 const TOOLS_TOKEN = '{{tools}}'
 
@@ -106,6 +110,61 @@ export interface Scenario {
    * test and the scenario needs an independent project location.
    */
   workspaceParent?: string
+  /**
+   * Whether Windows additionally compares stdout with native separators against
+   * `stdout.expected.windows.jsonl`. The shared canonical stdout expected output is still
+   * compared on every platform, and the fixture guard requires this sidecar
+   * exactly when the option is set.
+   */
+  pinsNativeWindowsStdout?: boolean
+  /**
+   * Whether the driven behavior needs POSIX process semantics the harness
+   * cannot exercise on Windows (e.g. cancelling a live bash tool call kills a
+   * detached process group). The scenario's run test is skipped on Windows;
+   * its fixtures stay guarded on every platform.
+   */
+  posixOnly?: boolean
+}
+
+/**
+ * Whether a scenario's run test is skipped for this mode and host: record mode
+ * skips authored (non-`recorded`) scenarios, and {@link Scenario.posixOnly}
+ * scenarios skip on Windows.
+ *
+ * @param scenario The scenario whose run test is being registered.
+ * @param recording Whether the suite runs in record mode.
+ * @param platform The running Node platform, injectable for unit coverage.
+ * @returns True when the scenario's run test must not execute.
+ */
+export function scenarioSkipped(
+  scenario: Scenario,
+  recording: boolean,
+  platform: NodeJS.Platform = process.platform,
+): boolean {
+  if (recording && !scenario.recorded) return true
+  return scenario.posixOnly === true && platform === 'win32'
+}
+
+/** One stdout expected output selected for a platform run. */
+interface StdoutExpectedVariant {
+  file: string
+  cwdPathMode: CwdPathMode
+}
+
+/**
+ * Select the shared stdout expected output plus any platform-native assertion declared by a scenario.
+ *
+ * @param scenario The scenario whose stdout contract is being selected.
+ * @param platform The running Node platform, injectable for unit coverage.
+ * @returns The ordered expected-output variants: shared canonical first, then optional Windows native.
+ */
+export function stdoutExpectedVariants(
+  scenario: Scenario,
+  platform: NodeJS.Platform = process.platform,
+): StdoutExpectedVariant[] {
+  const canonical: StdoutExpectedVariant = { file: 'stdout.expected.jsonl', cwdPathMode: 'canonical' }
+  if (platform !== 'win32' || scenario.pinsNativeWindowsStdout !== true) return [canonical]
+  return [canonical, { file: WINDOWS_STDOUT_SNAPSHOT, cwdPathMode: 'native' }]
 }
 
 /** One suite's inputs: the agent to boot, where its fixtures live, and its scenario table. */
@@ -426,8 +485,21 @@ export function stabilizeRefreshLog(fresh: string, existing: string, replacement
   for (const { from, to } of replacements) stable = stable.split(from).join(to)
   const existingRecords = parseJsonlRecords(existing)
   const records = parseJsonlRecords(stable)
+  let existingIndex = 0
+  let previousEventTime: unknown
   for (let i = 0; i < records.length; i++) {
-    preserveFixtureVolatiles(records[i] as Record<string, unknown>, existingRecords[i])
+    const record = records[i] as Record<string, unknown>
+    const existingRecord = existingRecords[existingIndex]
+    const insertedTitle = record.type === 'session/title' && existingRecord?.type !== 'session/title'
+    if (insertedTitle) {
+      /* v8 ignore next -- a title is turn-enclosed, so a preceding event time exists in every valid fixture. */
+      if (typeof previousEventTime !== 'number') throw new Error('acp-snapshot: inserted title has no preceding event time')
+      record.time = previousEventTime
+    } else {
+      preserveFixtureVolatiles(record, existingRecord)
+      existingIndex += 1
+    }
+    if (typeof record.time === 'number') previousEventTime = record.time
   }
   return records.map(record => JSON.stringify(record)).join('\n') + '\n'
 }
@@ -472,8 +544,9 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
   scenarioSuite('snapshot scenarios', () => {
     for (const scenario of scenarios) {
       // In RECORD mode, only re-run the `recorded` (live-API) scenarios; the `authored` ones
-      // (sidecar-driven errors/cancel) are never re-recorded.
-      it.skipIf(RECORDING && !scenario.recorded)(`snapshot: ${scenario.name} matches the expected outputs`, async ({ expect }) => {
+      // (sidecar-driven errors/cancel) are never re-recorded. `posixOnly` scenarios skip on
+      // Windows, where their process semantics cannot be driven.
+      it.skipIf(scenarioSkipped(scenario, RECORDING))(`snapshot: ${scenario.name} matches the expected outputs`, async ({ expect }) => {
         const dir = join(snapshotsDir, scenario.name)
         const input = JSON.parse(await readFile(join(dir, 'input.json'), 'utf8')) as InputScript
         const overrideFile = join(dir, 'replay.override.json')
@@ -578,11 +651,13 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
           }
         }
 
-        const stdout = normalizeStdout(result.rawStdout, ctx)
-        if (REFRESHING) {
-          await writeFile(join(dir, 'stdout.expected.jsonl'), stdout)
+        for (const expected of stdoutExpectedVariants(scenario)) {
+          const stdout = normalizeStdout(result.rawStdout, ctx, { cwdPathMode: expected.cwdPathMode })
+          if (REFRESHING) {
+            await writeFile(join(dir, expected.file), stdout)
+          }
+          await expect(stdout, `${expected.file} mismatch`).toMatchFileSnapshot(join(dir, expected.file))
         }
-        await expect(stdout).toMatchFileSnapshot(join(dir, 'stdout.expected.jsonl'))
 
         // A model turn always produces a log worth comparing; a hook scenario can
         // produce one without a model turn (a `rejected` turn carrying `hook/*`).
@@ -669,10 +744,14 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
 
     it('every registered scenario has its required fixture files', async () => {
       // Every scenario needs input, stdout, a primary session fixture, and matching optional sidecars.
-      for (const { name, overridden, pinsHeader } of scenarios) {
+      for (const { name, overridden, pinsHeader, pinsNativeWindowsStdout } of scenarios) {
         const dir = join(snapshotsDir, name)
         expect(existsSync(join(dir, 'input.json')), `${name}/input.json`).toBe(true)
         expect(existsSync(join(dir, 'stdout.expected.jsonl')), `${name}/stdout.expected.jsonl`).toBe(true)
+        expect(
+          existsSync(join(dir, WINDOWS_STDOUT_SNAPSHOT)),
+          `${name}/${WINDOWS_STDOUT_SNAPSHOT} presence must match \`pinsNativeWindowsStdout\``,
+        ).toBe(pinsNativeWindowsStdout === true)
         expect(existsSync(join(dir, 'session.jsonl')), `${name}/session.jsonl`).toBe(true)
         expect(existsSync(join(dir, 'replay.override.json')), `${name}/replay.override.json presence must match \`overridden\``)
           .toBe(overridden === true)