Merge remote-tracking branch 'origin/master' into feat/sandbox-support

# Conflicts: # packages/workflow/workflow-workerthread/tests/workflow-workerthread.spec.ts
2026-07-11 21:43:10 +08:00
parent b29a8eca71 ee3e4ea8f9
commit 1e2d8014a5
27 changed files with 1050 additions and 146 deletions
@@ -1102,4 +1102,5 @@ Imported as libraries by other packages; a `cordis.yml` cannot load them.
 - `@deepseek-ai/dsh-brand` ([`packages/util/brand/src/index.ts`](../packages/util/brand/src/index.ts))
 - `@deepseek-ai/dsh-hook-protocol` ([`packages/hooks/hook-protocol/src/index.ts`](../packages/hooks/hook-protocol/src/index.ts))
 - `@deepseek-ai/dsh-subagent-inprocess` ([`packages/subagent/subagent-inprocess/src/index.ts`](../packages/subagent/subagent-inprocess/src/index.ts))
+- `@deepseek-ai/dsh-subagent-subprocess` ([`packages/subagent/subagent-subprocess/src/index.ts`](../packages/subagent/subagent-subprocess/src/index.ts))
 - `@deepseek-ai/dsh-timeout` ([`packages/util/timeout/src/index.ts`](../packages/util/timeout/src/index.ts))
@@ -46,6 +46,7 @@ flowchart TD
    pkg_subagent_fork["subagent-fork"]
    pkg_subagent_inprocess["subagent-inprocess"]
    pkg_subagent_spawn["subagent-spawn"]
+    pkg_subagent_subprocess["subagent-subprocess"]
    pkg_tool_subagent["tool-subagent"]
  end
  subgraph group_web["packages/web"]
@@ -239,6 +240,7 @@ flowchart TD
  pkg_subagent_acp --> pkg_agent
  pkg_subagent_acp --> pkg_llm
  pkg_subagent_acp --> pkg_subagent
+  pkg_subagent_acp --> pkg_subagent_subprocess
  pkg_subagent_inprocess --> pkg_agent
  pkg_subagent_inprocess --> pkg_llm
  pkg_subagent_inprocess --> pkg_session
@@ -291,6 +293,7 @@ flowchart TD
 | --- | --- | --- |
 | [`brand`](../packages/util/brand) | `util` | — |
 | [`timeout`](../packages/util/timeout) | `util` | — |
+| [`subagent-subprocess`](../packages/subagent/subagent-subprocess) | `subagent` | — |
 | [`acp-snapshot`](../packages/support/acp-snapshot) | `support` | — |
 | [`app-boot`](../packages/ui/app-boot) | `ui` | — |
 | [`code-runtime`](../packages/code-runtime/code-runtime) | `code-runtime` | — |
@@ -340,7 +343,7 @@ flowchart TD
 | [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) | `guard` | [`agent`](../packages/core/agent), [`tools`](../packages/core/tools) |
 | [`tool-workflow`](../packages/workflow/tool-workflow) | `workflow` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools), [`workflow`](../packages/workflow/workflow) |
 | [`agent-core`](../packages/core/agent-core) | `core` | [`agent`](../packages/core/agent), [`agent-loop`](../packages/core/agent-loop), [`invariants`](../packages/support/invariants), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`system-prompt`](../packages/core/system-prompt), [`tool-bash`](../packages/bash/tool-bash), [`tools`](../packages/core/tools) |
-| [`subagent-acp`](../packages/subagent/subagent-acp) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent) |
+| [`subagent-acp`](../packages/subagent/subagent-acp) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent), [`subagent-subprocess`](../packages/subagent/subagent-subprocess) |
 | [`subagent-inprocess`](../packages/subagent/subagent-inprocess) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools) |
 | [`tool-subagent`](../packages/subagent/tool-subagent) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent), [`tools`](../packages/core/tools) |
 | [`hooks-claude`](../packages/hooks/hooks-claude) | `hooks` | [`agent`](../packages/core/agent), [`hook-protocol`](../packages/hooks/hook-protocol), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`tools`](../packages/core/tools) |
@@ -1,17 +1,17 @@
 # Testing policy

-How this repo tests, tier by tier, and the rules that keep a green suite meaning something. Commands live in the root [AGENTS.md](../AGENTS.md) § Commands; the RFCs linked per tier carry the design rationale.
+How this repo tests, tier by tier, and the rules that keep a green suite meaningful. Commands live in root [AGENTS.md](../AGENTS.md); linked RFCs carry the rationale.

 ## Tiers

- **Unit** (`pnpm run test`): vitest over `packages|examples/*/tests/**/*.spec.ts`, colocated with what they test. Every registry gets an HMR-safety test (dispose the contributing fiber, assert cleanup). Excessive tests are welcome — err toward covering edge cases, error paths, event ordering, and concurrency races; review findings get regression tests (see `packages/core/agent-loop/tests/review-fixes.spec.ts`).
+- **Unit** (`pnpm run test`): vitest over `packages|examples/*/tests/**/*.spec.ts`, colocated with what they test. Every registry gets an HMR-safety test (dispose the contributing fiber, assert cleanup). Prefer edge cases, error paths, event ordering, and concurrency races; review findings get regression tests (see `packages/core/agent-loop/tests/review-fixes.spec.ts`).
 - **Coverage gate** (`pnpm run test:coverage`): the gating run, per-file 100% on `packages/*/*/src`. An uncovered line is often dead code the gate is correctly flagging for deletion, not a missing test to bolt on. Line coverage is necessary, never sufficient — it proves lines ran, not that the feature works as shipped.
 - **Real-API e2e** (`pnpm run test:e2e`): with-key tests against live provider APIs — the DeepSeek model plus provider-specific smokes that gate on their own keys (`EXA_API_KEY`, `PERPLEXITY_API_KEY`, …); each suite self-skips without its key so keyless CI stays green ([real-API e2e RFC](rfc/implemented/testing/2026-06-19-real-api-e2e-ci.md)).
- **Snapshot** (`pnpm run test:snapshot`): boots the real example subprocess, replays a recorded session keyless, diffs normalized stdout + the re-persisted log against committed goldens ([snapshot RFC](rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md)). Re-record with `pnpm run test:snapshot:record`; reviewing the golden diff is part of the review. System-prompt/tool-schema content is pinned by ONE scenario (`text-turn`) and tokenized in every other fixture, so a prompt or schema edit churns one committed line ([pinned-header RFC](rfc/implemented/testing/2026-07-06-pin-request-header-content-in-one-scenario.md)).
+- **Snapshot** (`pnpm run test:snapshot`): boots the real example subprocess, replays a recorded session keyless, diffs normalized stdout + the re-persisted log against committed goldens ([snapshot RFC](rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md)). Use `pnpm run test:snapshot:record` when the model transcript should change; use `pnpm run test:snapshot:refresh` when the committed transcript is still the right mock LLM input and replay goldens need keyless rewrite. Review the golden diff. System-prompt/tool-schema content is pinned by ONE scenario (`text-turn`) and tokenized in every other fixture, so a prompt or schema edit churns one committed line ([pinned-header RFC](rfc/implemented/testing/2026-07-06-pin-request-header-content-in-one-scenario.md)).

 ## The with-key policy: inference is cheap here

-We are DeepSeek — do not ration real-API tests. A no-key test proves the plumbing; only a with-key run proves the agent works against a real model. Write many: real prompts that write files, multi-turn conversations, tool use, cancellation mid-stream. Cheapest and highest-value are **smoke tests** that boot the real example, send one real prompt, and check the world — they catch the "green unit tests, broken product" class that mocks structurally cannot ([postmortem 0001](postmortem/0001-acp-default-export-drops-inject.md)). The self-skip exists only so secretless CI and keyless contributors aren't blocked; it is not a cost signal. Every example ships a keyless smoke and — unless keyless-by-nature — a with-key smoke ([examples/AGENTS.md](../examples/AGENTS.md)).
+We are DeepSeek — do not ration real-API tests. A no-key test proves plumbing; only a with-key run proves the agent works against a real model. Write many: file-writing prompts, multi-turn conversations, tool use, cancellation mid-stream. Highest-value are **smoke tests** that boot the real example, send one real prompt, and check the world — they catch the "green unit tests, broken product" class that mocks structurally cannot ([postmortem 0001](postmortem/0001-acp-default-export-drops-inject.md)). The self-skip exists only so secretless CI and keyless contributors aren't blocked; it is not a cost signal. Every example ships a keyless smoke and — unless keyless-by-nature — a with-key smoke ([examples/AGENTS.md](../examples/AGENTS.md)).

 ## Prefer the real implementation over a mock

@@ -39,7 +39,14 @@ export default tseslint.config(
    ],
    languageOptions: {
      parserOptions: {
-        project: ['./packages/*/*/tsconfig.json', './tsconfig.json'],
+        // One shared tsserver-style project service instead of 60+ standalone
+        // per-package programs: the old `project` glob built every package's
+        // full dependency closure (sibling sources via the dev `paths` map +
+        // the vendored Cordis stack) as its own program and kept them all
+        // resident — ~5 GB peak, an OOM past node's default heap. The service
+        // resolves each file to its nearest owning tsconfig and shares the
+        // graph.
+        projectService: true,
        tsconfigRootDir: import.meta.dirname,
      },
    },
@@ -90,7 +97,9 @@ export default tseslint.config(
    ],
    languageOptions: {
      parserOptions: {
-        project: ['./tsconfig.json'],
+        // Same shared project service as the src block: test files resolve
+        // through the root tsconfig (its include covers every tests/ tree).
+        projectService: true,
        tsconfigRootDir: import.meta.dirname,
      },
    },
@@ -33,7 +33,7 @@ The editor sets each session's `cwd` to the project it opens; both the agent's b

 ## Snapshot tests (record-once / replay-deterministic)

-This example is the home of the harness's **snapshot tests** — they boot this server as a real subprocess, drive it with a deterministic input script, and diff its normalized output against committed golden files. The model is made deterministic by `@deepseek-ai/dsh-llm-replay`, a function/namespace plugin that installs an `llm/stream` waterfall listener and short-circuits it, serving model streams reconstructed from a recorded **session JSONL** fixture (`<scenario>/session.jsonl`) — so replay needs no API key. The fixture IS the persisted session log: its `assistant/chunk` events carry every `StreamChunk`, so grouping them by `(turn, step)` reconstructs each `stream()` call (one model call per loop step). Recording is therefore "run the real agent once and harvest the `.jsonl`". The two failure modes not expressible as logged chunks — a pure throw before any chunk, and cancel/hang — use an optional `<scenario>/replay.override.json` sidecar (a `ReplayEntry[]` that replaces the derived script). A scenario that needs the agent to operate on existing files ships an optional `<scenario>/workspace/` directory — the harness copies its contents into the temp cwd before the run (see `workspace-edit`). See [the ACP snapshot tests RFC](../../docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md) for the full design.
+This example is the home of the harness's **snapshot tests** — they boot this server as a real subprocess, drive it with a deterministic input script, and diff its normalized output against committed golden files. The model is made deterministic by `@deepseek-ai/dsh-llm-replay`, a function/namespace plugin that installs an `llm/stream` waterfall listener and short-circuits it, serving model streams reconstructed from a recorded **session JSONL** fixture (`<scenario>/session.jsonl`) — so replay needs no API key. The fixture IS the persisted session log: its `assistant/chunk` events carry every `StreamChunk`, so grouping them by `(turn, step)` reconstructs each `stream()` call (one model call per loop step). Recording is therefore "run the real agent once and harvest the `.jsonl`"; use `pnpm run test:snapshot:record` when the model transcript itself should change, and `pnpm run test:snapshot:refresh` when the committed model transcript is still the right mock input and only the current replay output/goldens need to be rewritten. The two failure modes not expressible as logged chunks — a pure throw before any chunk, and cancel/hang — use an optional `<scenario>/replay.override.json` sidecar (a `ReplayEntry[]` that replaces the derived script). A scenario that needs the agent to operate on existing files ships an optional `<scenario>/workspace/` directory — the harness copies its contents into the temp cwd before the run (see `workspace-edit`). See [the ACP snapshot tests RFC](../../docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md) for the full design.

 ## MVP limitations

@@ -1,15 +1,16 @@
 import { fileURLToPath } from 'node:url'
 import { dirname, join } from 'node:path'
-import { defineAcpSnapshotSuite, type Scenario } from '@deepseek-ai/dsh-acp-snapshot'
+import { defineAcpSnapshotSuite, type Scenario, type SnapshotSuiteOptions } from '@deepseek-ai/dsh-acp-snapshot'

 /**
 * The acp-agent example's snapshot suite: the scenario table for
 * `dsh-acp-snapshot`'s suite factory, which owns every compare/guard mechanic
- * (golden + re-persisted-log diffs, record write-back, the pinned-header
+ * (golden + re-persisted-log diffs, record/refresh write-back, the pinned-header
 * uniformity guard, the fixture guards). Fixtures live under `snapshots/<name>/`;
- * `pnpm run test:snapshot:record` re-records the `recorded` scenarios against
- * the real API. See the package README (packages/support/acp-snapshot) and the
- * snapshot RFC, docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md.
+ * `pnpm run test:snapshot:record` re-records model transcripts against the real
+ * API; `pnpm run test:snapshot:refresh` rewrites current replay goldens keyless.
+ * See the package README (packages/support/acp-snapshot) and the snapshot RFC,
+ * docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md.
 */

 // The dsh-acp-agent bin (the demo:acp entry), this example's cordis.yml, and
@@ -26,6 +27,21 @@ const AGENT = {
 const CODE_MODE_CONFIG = fileURLToPath(new URL('../code-mode.cordis.yml', import.meta.url))
 const BOTH_MODE_CONFIG = fileURLToPath(new URL('../both-mode.cordis.yml', import.meta.url))

+function snapshotModeFromEnv(value: string | undefined): SnapshotSuiteOptions['mode'] {
+  switch (value) {
+    case undefined:
+    case '':
+    case 'replay':
+      return 'replay'
+    case 'record':
+      return 'record'
+    case 'refresh':
+      return 'refresh'
+    default:
+      throw new Error(`unknown DSH_SNAPSHOT mode: ${value}`)
+  }
+}
+
 const SCENARIOS: Scenario[] = [
  { name: 'handshake', hasModelTurn: false, recorded: false },
  { name: 'reject-extra-dirs', hasModelTurn: false, recorded: false },
@@ -111,5 +127,5 @@ defineAcpSnapshotSuite({
  agent: AGENT,
  snapshotsDir: join(dirname(fileURLToPath(import.meta.url)), 'snapshots'),
  scenarios: SCENARIOS,
-  mode: process.env.DSH_SNAPSHOT === 'record' ? 'record' : 'replay',
+  mode: snapshotModeFromEnv(process.env.DSH_SNAPSHOT),
 })
@@ -89,6 +89,11 @@
      "entry": ["tests/**/*.spec.ts", "tests/**/*.e2e.ts", "tests/mock-acp-server.ts"],
      "project": ["src/**/*.ts", "tests/**/*.ts"]
    },
+    "packages/subagent/subagent-subprocess": {
+      "entry": ["tests/**/*.spec.ts"],
+      "project": ["src/**/*.ts", "tests/**/*.ts"],
+      "ignoreDependencies": ["cordis"]
+    },
    "packages/fs/tool-fs": {
      "entry": ["tests/**/*.spec.ts", "tests/**/*.e2e.ts"],
      "project": ["src/**/*.ts", "tests/**/*.ts"]
@@ -22,6 +22,7 @@
    "test:e2e": "vitest run --config vitest.e2e.config.ts",
    "test:snapshot": "vitest run --config vitest.snapshot.config.ts",
    "test:snapshot:record": "DSH_SNAPSHOT=record vitest run --config vitest.snapshot.config.ts --update",
+    "test:snapshot:refresh": "DSH_SNAPSHOT=refresh vitest run --config vitest.snapshot.config.ts",
    "check:ci": "tsx scripts/run-gates.ts ci-primary",
    "check:ci:static": "tsx scripts/run-gates.ts ci-static",
    "check:ci:lint": "tsx scripts/run-gates.ts ci-lint",
@@ -8,9 +8,10 @@ The subagent seam: an agent delegating work to a child agent. Like the [bash](..
 | `subagent-inprocess/` | Shared in-process run driver (pure lib; registers nothing) | — |
 | `subagent-spawn/` | In-process backend: a fresh child agent | (registers on `ctx.subagents`) |
 | `subagent-fork/` | In-process backend: a child seeded with the parent's completed-turn prefix | (registers on `ctx.subagents`) |
+| `subagent-subprocess/` | Shared out-of-process machinery: env scrub, dispose ladder, isolated config dirs (pure lib; registers nothing) | — |
 | `subagent-acp/` | Out-of-process backend: a child agent in a spawned subprocess, driven over ACP | (registers on `ctx.subagents`) |
 | `tool-subagent/` | Model-facing `subagent` delegation tool over `ctx.subagents` | (registers on `ctx.tools`) |

-The interface lives at `subagent/subagent/`. The in-process `subagent-spawn` / `subagent-fork` backends share the `subagent-inprocess` driver (a pure library — both depend on it, neither on the other), and the out-of-process `subagent-acp` backend ships alongside them here; the test-only `dsh-subagent-mock` (in [support](../support/README.md)) is separate. All **product** packages except the mock.
+The interface lives at `subagent/subagent/`. The in-process `subagent-spawn` / `subagent-fork` backends share the `subagent-inprocess` driver (a pure library — both depend on it, neither on the other), the out-of-process `subagent-acp` backend builds on the `subagent-subprocess` library (the credential env scrub, the dispose ladder, isolated config dirs) and ships alongside them here; the test-only `dsh-subagent-mock` (in [support](../support/README.md)) is separate. All **product** packages except the mock.

 The proposal and design rationale: [docs/rfc/implemented/feature/2026-06-21-subagent-capability-seam.md](../../docs/rfc/implemented/feature/2026-06-21-subagent-capability-seam.md).
@@ -57,7 +57,7 @@ A spawn/transport/RPC failure resolves `error` (or `aborted` if a cancel was req

 ## Environment scrub

-Credential-shaped ambient vars (`/KEY|SECRET|TOKEN/i`) are NOT forwarded to the child by default — the parent harness's own secrets must not leak into a spawned process implicitly. The child's OWN credentials are supplied explicitly via `config.env`, layered AFTER the scrub, so an intended `DEEPSEEK_API_KEY` survives while an incidental `AWS_SECRET_ACCESS_KEY` does not.
+The child env is built by [`buildChildEnv` from `@deepseek-ai/dsh-subagent-subprocess`](../subagent-subprocess/README.md) — the ambient env minus credential-shaped vars, with `config.env` layered on top after the scrub; the pattern and full semantics live there. For this backend that means the parent harness's own secrets never leak into the spawned agent implicitly, while the child's OWN `DEEPSEEK_API_KEY` is supplied deliberately via `config.env` and survives.

 ## Testing

@@ -25,6 +25,7 @@
    "@deepseek-ai/dsh-agent": "^0.0.1",
    "@deepseek-ai/dsh-llm": "^0.0.1",
    "@deepseek-ai/dsh-subagent": "^0.0.1",
+    "@deepseek-ai/dsh-subagent-subprocess": "^0.0.1",
    "cordis": "^4.0.0-rc.6"
  },
  "dependencies": {
@@ -35,6 +36,7 @@
    "@deepseek-ai/dsh-agent": "workspace:^",
    "@deepseek-ai/dsh-llm": "workspace:^",
    "@deepseek-ai/dsh-subagent": "workspace:^",
+    "@deepseek-ai/dsh-subagent-subprocess": "workspace:^",
    "@cordisjs/plugin-loader": "^1.0.0-rc.4",
    "cordis": "^4.0.0-rc.6"
  }
@@ -22,7 +22,7 @@
 * @module @deepseek-ai/dsh-subagent-acp/run
 */

-import { spawn, type ChildProcess } from 'node:child_process'
+import { spawn } from 'node:child_process'
 import { randomUUID } from 'node:crypto'
 import { Readable, Writable } from 'node:stream'
 import {
@@ -40,6 +40,7 @@ import {
 import { AgentId } from '@deepseek-ai/dsh-agent'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
 import type { SubagentResult, SubagentRun, SubagentStartRequest, SubagentStopReason } from '@deepseek-ai/dsh-subagent'
+import { buildChildEnv, disposeChildProcess, spawnFailure } from '@deepseek-ai/dsh-subagent-subprocess'

 /**
 * How the client answers a child's `session/request_permission`. The first cut
@@ -88,6 +89,7 @@ export interface AcpRunSpec {
   * (the seam contract forbids `result` rejecting). The driver calls this with
   * the original error and the chosen stop reason so the fault is preserved
   * rather than silently lost; the provider wires it to `ctx.logger.warn`.
+   * A throw from the sink itself is contained — it cannot reject `result`.
   * Optional — omitted in a unit test that asserts the stop reason directly.
   */
  onError?: (error: Error, stopReason: SubagentStopReason) => void
@@ -110,31 +112,6 @@ export const DEFAULT_DISPOSE_EOF_GRACE_MS = 6_000
 /** Default grace between SIGTERM and SIGKILL on dispose (the `disposeGraceMs` config; mirrors the bash executor). */
 export const DEFAULT_DISPOSE_GRACE_MS = 3_000

-/**
- * Credential-shaped ambient env vars are NOT forwarded to the child by default
- * (the parent harness's own `DEEPSEEK_API_KEY`/secrets must not leak into a
- * spawned process implicitly). Same pattern as the bash executor. The child
- * agent needs its OWN credentials to reach a model — those are supplied
- * explicitly via {@link AcpRunSpec.env}, which is layered on top AFTER the
- * scrub, so an intended `DEEPSEEK_API_KEY` survives while an incidental
- * `AWS_SECRET_ACCESS_KEY` does not.
- */
-export const SENSITIVE_ENV_PATTERN = /KEY|SECRET|TOKEN/i
-
-/**
- * The ambient env minus credential-shaped vars, plus the spec's explicit env.
- * @param extra - explicit vars layered on top AFTER the scrub, so a
- * credential-shaped name supplied deliberately still reaches the child.
- * @returns the environment to spawn the child with.
- */
-export function buildChildEnv(extra: Record<string, string>): NodeJS.ProcessEnv {
-  const env: NodeJS.ProcessEnv = {}
-  for (const [key, value] of Object.entries(process.env)) {
-    if (!SENSITIVE_ENV_PATTERN.test(key)) env[key] = value
-  }
-  return { ...env, ...extra }
-}
-
 /**
 * Map an ACP {@link StopReason} to a harness {@link SubagentStopReason}.
 * @param reason - the terminal reason from the child's `session/prompt` response.
@@ -196,24 +173,6 @@ function toError(value: unknown): Error {
  return value instanceof Error ? value : new Error(String(value))
 }

-/** Resolve once the child process exits (any code/signal); immediate if gone. */
-function waitForExit(child: ChildProcess): Promise<void> {
-  // Already-exited fast path: dispose guards on exitCode before calling, so in
-  // tests the child is always still alive here.
-  /* v8 ignore next */
-  if (child.exitCode !== null || child.signalCode !== null) return Promise.resolve()
-  return new Promise<void>(resolve => child.once('exit', () => { resolve() }))
-}
-
-/** Resolve `true` if the child exits within `ms`, `false` on timeout. */
-function exitsWithin(child: ChildProcess, ms: number): Promise<boolean> {
-  return Promise.race([
-    waitForExit(child).then(() => true),
-    // `.unref()` so a pending grace timer never keeps the parent's loop alive.
-    new Promise<boolean>(resolve => setTimeout(() => { resolve(false) }, ms).unref()),
-  ])
-}
-
 /**
 * Start an out-of-process ACP child for `request` and return a {@link SubagentRun}.
 *
@@ -254,13 +213,11 @@ export function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpec): Su
    env: buildChildEnv(spec.env),
    stdio: ['pipe', 'pipe', 'inherit'],
  })
-  // A spawn-level failure (e.g. ENOENT for a bad command) is emitted as an
-  // `error` event, NOT a thrown exception — without a listener Node treats it as
-  // an unhandled error and crashes the parent. Capture it into a promise the
-  // result path races, so a bad command settles `error` like any child failure.
-  const spawnFailed = new Promise<Error>((resolve) => {
-    child.once('error', (err) => { resolve(err) })
-  })
+  // Same-tick capture (the library's contract): a spawn-level failure (e.g.
+  // ENOENT for a bad command) is an `error` EVENT that would crash the parent
+  // unheard; the result path races this promise, so a bad command settles
+  // `error` like any child failure.
+  const spawnFailed = spawnFailure(child)

  // Accumulate the child's streamed assistant text — the SubagentResult output.
  const output: string[] = []
@@ -380,7 +337,13 @@ export function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpec): Su
      // (initialize/newSession/prompt transport/RPC errors, or ENOENT), not a
      // local bug. Flatten to `error` and surface the original via onError so a
      // real fault is preserved rather than silently lost.
-      spec.onError?.(toError(error), 'error')
+      try {
+        spec.onError?.(toError(error), 'error')
+      } catch {
+        // Swallows only the caller-supplied sink's OWN throw: an unguarded
+        // sink exception would reject `result` and break the contract above.
+        // The child-level failure being reported still settles as `error`.
+      }
      return { output: collectOutput(), stopReason: 'error' }
    }
  })()
@@ -393,33 +356,19 @@ export function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpec): Su
    },
    async dispose(): Promise<void> {
      request.signal?.removeEventListener('abort', onAbort)
-      // Reach quiescence, not merely request it (dispose must AWAIT the child
-      // actually stopping). If the child is already gone, nothing to do.
-      if (child.exitCode !== null || child.signalCode !== null) return
-      const eofGraceMs = spec.disposeEofGraceMs
-      const graceMs = spec.disposeGraceMs
-      // 1. Graceful: end the ACP request stream (stdin EOF) and let the child
-      //    quiesce ON ITS OWN. Our acp-agent has NO SIGTERM handler in a normal
-      //    session — it tears down via the server bridge's connection-close path
-      //    (conn.closed → per-agent dispose → final session/flush), driven by the
-      //    stdin EOF, NOT by a signal. A prompt response can resolve from a
-      //    turn/end BEFORE that post-turn flush lands, so the child still has
-      //    durable work owed when dispose runs. Give the EOF-driven quiesce a real
-      //    window — wider than a single signal-grace, since the child's own
-      //    teardown may itself be awaiting a signal-trapping grandchild (a bash
-      //    subprocess in its own SIGTERM→SIGKILL grace) plus a flush — and only
-      //    escalate if it overruns. Sending SIGTERM in the same tick (or too soon)
-      //    would default-terminate the child mid-flush, orphaning its nested work.
-      child.stdin.end()
-      if (await exitsWithin(child, eofGraceMs)) return
-      // 2. SIGTERM, then escalate to SIGKILL if it still does not exit within the
-      //    grace period — a child that ignores EOF and traps SIGTERM must not
-      //    wedge dispose forever (the seam requires bounded quiescence).
-      child.kill('SIGTERM')
-      if (await exitsWithin(child, graceMs)) return
-      // 3. Force-kill and await the (now-certain) exit.
-      child.kill('SIGKILL')
-      await waitForExit(child)
+      // Quiescent teardown via the shared ladder (stdin EOF → SIGTERM →
+      // SIGKILL, awaiting the actual exit). For THIS child the EOF tier is the
+      // one that matters: our acp-agent has NO SIGTERM handler in a normal
+      // session — it tears down via the server bridge's connection-close path
+      // (conn.closed → per-agent dispose → final session/flush), driven by the
+      // stdin EOF, NOT by a signal — and a prompt response can resolve from a
+      // turn/end BEFORE that post-turn flush lands, so the child still has
+      // durable work owed when dispose runs (hence the wide EOF grace; see
+      // DEFAULT_DISPOSE_EOF_GRACE_MS).
+      await disposeChildProcess(child, {
+        disposeEofGraceMs: spec.disposeEofGraceMs,
+        disposeGraceMs: spec.disposeGraceMs,
+      })
    },
  }
 }
@@ -6,9 +6,10 @@ import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { fileURLToPath } from 'node:url'
 import SubagentService from '@deepseek-ai/dsh-subagent'
+import { buildChildEnv, SENSITIVE_ENV_PATTERN } from '@deepseek-ai/dsh-subagent-subprocess'
 import type { Agent } from '@deepseek-ai/dsh-agent'
 import * as acp from '../src/index.ts'
-import { acpStopReason, acpContentText, buildChildEnv, DEFAULT_DISPOSE_EOF_GRACE_MS, DEFAULT_DISPOSE_GRACE_MS, SENSITIVE_ENV_PATTERN, startAcpRun, toAcpPrompt, type AcpRunSpec } from '../src/run.ts'
+import { acpStopReason, acpContentText, DEFAULT_DISPOSE_EOF_GRACE_MS, DEFAULT_DISPOSE_GRACE_MS, startAcpRun, toAcpPrompt, type AcpRunSpec } from '../src/run.ts'

 /**
 * Keyless integration tests for the ACP subagent backend. Each spawns a REAL
@@ -482,6 +483,28 @@ describe('dsh-subagent-acp', () => {
    await run.dispose()
  })

+  it('resolves error (never rejects) even when the onError sink itself throws', async () => {
+    // onError is a caller-supplied callback boundary: its own exception must be
+    // contained, or it would reject `result` and break the seam's "result never
+    // rejects" contract that the flattening above exists to uphold.
+    const run = startAcpRun(
+      { prompt: [{ type: 'text', text: 'p' }], parent: fakeParent },
+      {
+        command: '/nonexistent/acp-agent-binary',
+        args: [],
+        cwd: process.cwd(),
+        permission: 'reject',
+        env: {},
+        disposeEofGraceMs: DEFAULT_DISPOSE_EOF_GRACE_MS,
+        disposeGraceMs: DEFAULT_DISPOSE_GRACE_MS,
+        onError: () => { throw new Error('sink boom') },
+      },
+    )
+    const result = await run.result
+    expect(result.stopReason).toBe('error')
+    await run.dispose()
+  })
+
  it('settles aborted when the child crashes (tears the pipe) AFTER a cancel', async () => {
    // The child hangs, we cancel, and instead of answering the child exits hard
    // — the pending prompt RPC rejects. With a cancel already requested, the
@@ -25,6 +25,9 @@
    },
    {
      "path": "../subagent"
+    },
+    {
+      "path": "../subagent-subprocess"
    }
  ]
 }
@@ -0,0 +1,40 @@
+# @deepseek-ai/dsh-subagent-subprocess
+
+Shared machinery for **out-of-process subagent backends** — providers that spawn an external agent as a child process, such as the [ACP backend](../subagent-acp/README.md). A pure library (no provider, no registration, no Config): what every spawn-a-CLI-child backend needs to keep the parent deployment's credentials out of the child, tear the child down to quiescence, and isolate it from the host user's on-disk CLI state. Design rationale: [the Claude Code / Codex subagent backends RFC](../../../docs/rfc/proposed/feature/2026-07-07-claude-code-and-codex-subagent-backends.md).
+
+Every tunable is a **parameter**: the dispose ladder takes its grace periods per call, the config-dir helper takes an optional pinned path. Defaults live in each consuming plugin's Config (defaulted, validated fields changeable from `cordis.yml`), never in this library.
+
+## What it exports
+
+### `SENSITIVE_ENV_PATTERN` / `buildChildEnv(extra)`
+
+The credential env scrub (same pattern as the [bash executor](../../bash/bash-local/README.md)): the child env is the ambient env minus credential-shaped vars (`/KEY|SECRET|TOKEN/i`), with `extra` layered on top AFTER the scrub. `PATH`, `HOME`, `TMPDIR`, locale, and proxy vars survive, so the child CLI runs normally; the parent's own secrets never leak implicitly, while an explicitly supplied credential (the child's OWN key in a backend's `env` config) still reaches the child.
+
+### `spawnFailure(child)`
+
+Spawn-failure capture: a promise that resolves (never rejects) with the child's first `error` event. A spawn failure such as `ENOENT` is an event, not a thrown exception — without a listener Node crashes the parent process — so call this in the same tick as `spawn()` and race it in the run's result path; a bad command then settles as an ordinary child-level failure. For a child that spawns cleanly the promise never settles.
+
+### `waitForExit(child)` / `exitsWithin(child, ms)`
+
+Exit waits over a `ChildProcess`: resolve once the child exits by any code or signal (immediately if it is already gone), or race that against a timer (`true` = exited in time). The race cleans up after itself on both outcomes — the pending timer is `unref()`ed and cleared on exit, the exit listener removed on timeout — so repeated calls (the dispose ladder's tiers, a poll loop) never accumulate listeners on the child.
+
+### `disposeChildProcess(child, graces)`
+
+The three-tier dispose ladder. Resolves only once the child has ACTUALLY exited — quiescence reached, not merely requested (see [defensive patterns](../../../docs/defensive-patterns.md)):
+
+1. stdin EOF (when stdin is piped), then wait `graces.disposeEofGraceMs` — a cooperative child quiesces on its own, its flushes and nested-subprocess teardown intact;
+2. `SIGTERM`, then wait `graces.disposeGraceMs`;
+3. `SIGKILL`, then await the now-certain exit — a child that ignores EOF and traps `SIGTERM` cannot wedge dispose forever.
+
+The two graces (`DisposeLadderGraces`) come from the consuming plugin's `disposeEofGraceMs`/`disposeGraceMs` Config fields; the EOF window is deliberately a separate — usually wider — grace than the signal tier, since a cooperative child's EOF teardown may itself await a signal-trapping grandchild plus a final flush.
+
+### `createIsolatedConfigDir(prefix, pinnedPath?)`
+
+A per-run isolated config directory for an external CLI child (the target of `CLAUDE_CONFIG_DIR` / `CODEX_HOME`-style redirection), so child behavior is a function of deployment config alone — never of whatever `~/.claude` / `~/.codex`-style state exists on the host. Returns an `IsolatedConfigDir` handle: `path` goes into the child env, `remove()` runs on dispose.
+
+- **Fresh (default)**: a private (0700) `mkdtemp` dir under the OS temp root; `remove()` deletes it best-effort (never rejects — a leftover temp dir beats a failed dispose) and is idempotent.
+- **Pinned** (`pinnedPath` set): the path is returned as-is — never created, never removed. A deployment that pins a directory to share child state across runs owns that directory's lifecycle.
+
+## Testing
+
+`tests/subagent-subprocess.spec.ts`: the env scrub and config-dir helpers run against the real process env and real filesystem (the rm-failure path injects its rejection at the fs boundary — a real recursive-rm failure is not portably provokable, and root ignores permission bits); the exit waits and the dispose ladder run against a scriptable fake child, driving each escalation tier deterministically. The [ACP backend suite](../subagent-acp/README.md) exercises the same ladder against real subprocesses (EOF-cooperative, EOF-ignoring, and SIGTERM-trapping children) end to end.
@@ -0,0 +1,30 @@
+{
+  "name": "@deepseek-ai/dsh-subagent-subprocess",
+  "description": "Shared out-of-process subagent machinery: credential env scrub, spawn-failure capture, child-exit waits, the EOF-to-SIGTERM-to-SIGKILL dispose ladder, and isolated config dirs (pure lib; registers nothing)",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ],
+  "license": "BSD-3-Clause",
+  "peerDependencies": {
+    "cordis": "^4.0.0-rc.6"
+  },
+  "devDependencies": {
+    "cordis": "^4.0.0-rc.6"
+  }
+}
@@ -0,0 +1,219 @@
+/**
+ * Shared machinery for OUT-OF-PROCESS subagent backends — providers that spawn
+ * an external agent as a child process and must keep the parent deployment's
+ * credentials out of it, tear it down to quiescence, and isolate it from the
+ * host user's on-disk CLI state. The pieces: the credential env scrub
+ * ({@link SENSITIVE_ENV_PATTERN} / {@link buildChildEnv}), the spawn-failure
+ * capture ({@link spawnFailure}), the child-exit waits ({@link waitForExit} /
+ * {@link exitsWithin}), the stdin-EOF → SIGTERM → SIGKILL dispose ladder
+ * ({@link disposeChildProcess}), and the per-run isolated config dir
+ * ({@link createIsolatedConfigDir}).
+ *
+ * This package owns no provider and registers nothing; it is a pure library
+ * the out-of-process backend packages depend on (the `subagent-inprocess`
+ * shape, for the process boundary). Every tunable — the ladder's grace
+ * periods, a pinned config dir — is a PARAMETER here: defaults belong in each
+ * consuming plugin's Config, per the no-hardcoded-tunables rule.
+ *
+ * @module @deepseek-ai/dsh-subagent-subprocess
+ */
+
+import type { ChildProcess } from 'node:child_process'
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+
+/**
+ * Credential-shaped ambient env vars are NOT forwarded to a child by default
+ * (the parent harness's own `DEEPSEEK_API_KEY`/secrets must not leak into a
+ * spawned process implicitly). Same pattern as the bash executor. The child
+ * agent needs its OWN credentials to reach a model — those are supplied
+ * explicitly via the `extra` layer of {@link buildChildEnv}, which lands AFTER
+ * the scrub, so an intended `DEEPSEEK_API_KEY` survives while an incidental
+ * `AWS_SECRET_ACCESS_KEY` does not.
+ */
+export const SENSITIVE_ENV_PATTERN = /KEY|SECRET|TOKEN/i
+
+/**
+ * The ambient env minus credential-shaped vars, plus the caller's explicit
+ * env. `PATH`, `HOME`, `TMPDIR`, locale, and proxy vars survive the scrub, so
+ * a child CLI runs normally; only {@link SENSITIVE_ENV_PATTERN}-shaped names
+ * are dropped.
+ * @param extra - explicit vars layered on top AFTER the scrub, so a
+ * credential-shaped name supplied deliberately still reaches the child.
+ * @returns the environment to spawn the child with.
+ */
+export function buildChildEnv(extra: Record<string, string>): NodeJS.ProcessEnv {
+  const env: NodeJS.ProcessEnv = {}
+  for (const [key, value] of Object.entries(process.env)) {
+    if (!SENSITIVE_ENV_PATTERN.test(key)) env[key] = value
+  }
+  return { ...env, ...extra }
+}
+
+/**
+ * Capture the child's spawn-level failure as a promise the run's result path
+ * can race. A spawn failure (e.g. `ENOENT` for a bad command) is emitted as an
+ * `error` EVENT, not a thrown exception — and without a listener Node treats
+ * it as an unhandled error and crashes the parent process. Call this in the
+ * SAME TICK as `spawn()`, so no window exists for the event to fire unheard.
+ * @param child - the just-spawned child process.
+ * @returns a promise that RESOLVES (never rejects) with the child's first
+ * `error` event; for a child that spawns cleanly it never settles.
+ */
+export function spawnFailure(child: ChildProcess): Promise<Error> {
+  return new Promise<Error>((resolve) => {
+    child.once('error', (err) => { resolve(err) })
+  })
+}
+
+/**
+ * Resolve once the child process exits (any code/signal); immediate if it is
+ * already gone.
+ * @param child - the child process to await.
+ */
+export function waitForExit(child: ChildProcess): Promise<void> {
+  if (child.exitCode !== null || child.signalCode !== null) return Promise.resolve()
+  return new Promise<void>(resolve => child.once('exit', () => { resolve() }))
+}
+
+/**
+ * Race the child's exit against a timer. Neither outcome leaves anything
+ * behind on the child: the exit listener is removed on timeout and the timer
+ * is cleared on exit, so repeated calls (the dispose ladder's tiers, a poll
+ * loop) never accumulate listeners.
+ * @param child - the child process to watch.
+ * @param ms - the wait window in milliseconds.
+ * @returns `true` if the child exits within `ms` (immediately if it is
+ * already gone), `false` on timeout.
+ */
+export function exitsWithin(child: ChildProcess, ms: number): Promise<boolean> {
+  if (child.exitCode !== null || child.signalCode !== null) return Promise.resolve(true)
+  return new Promise<boolean>((resolve) => {
+    const onExit = (): void => {
+      clearTimeout(timer)
+      resolve(true)
+    }
+    // `.unref()` so a pending grace timer never keeps the parent's loop alive.
+    const timer = setTimeout(() => {
+      child.removeListener('exit', onExit)
+      resolve(false)
+    }, ms).unref()
+    child.once('exit', onExit)
+  })
+}
+
+/**
+ * The two grace periods of the dispose ladder, supplied per call by the
+ * consuming backend — each plugin carries them as defaulted, validated
+ * `disposeEofGraceMs`/`disposeGraceMs` Config fields, so teardown timing is
+ * deployment-tunable and this library hardcodes nothing.
+ */
+export interface DisposeLadderGraces {
+  /**
+   * Tier-1 window (ms): after stdin EOF, how long the child gets to quiesce
+   * ON ITS OWN — flush durable state, tear down its own nested subprocesses —
+   * before the parent escalates to `SIGTERM`. A separate (usually WIDER)
+   * grace than {@link DisposeLadderGraces.disposeGraceMs}: a cooperative
+   * child's EOF-driven teardown may itself be waiting on a signal-trapping
+   * grandchild plus a final flush, needing more than one signal-grace of
+   * headroom.
+   */
+  disposeEofGraceMs: number
+  /** Tier-2 window (ms): between `SIGTERM` and the `SIGKILL` escalation. */
+  disposeGraceMs: number
+}
+
+/**
+ * Tear a child process down to QUIESCENCE: resolves only once the child has
+ * actually exited (or was already gone), never merely after requesting it.
+ * Three-tier escalation —
+ *
+ * 1. stdin EOF (when stdin is piped), then wait `disposeEofGraceMs`: a
+ *    cooperative child quiesces on its own, its teardown and flushes intact;
+ * 2. `SIGTERM`, then wait `disposeGraceMs`;
+ * 3. `SIGKILL`, then await the (now-certain) exit — a child that ignores EOF
+ *    and traps `SIGTERM` must not wedge dispose forever.
+ *
+ * @param child - the child process to tear down.
+ * @param graces - the two grace periods, from the consuming plugin's Config.
+ */
+export async function disposeChildProcess(child: ChildProcess, graces: DisposeLadderGraces): Promise<void> {
+  // Already gone: nothing to reap.
+  if (child.exitCode !== null || child.signalCode !== null) return
+  // 1. Graceful: end the request stream (stdin EOF) and let the child quiesce
+  //    on its own. Sending SIGTERM in the same tick (or too soon) would
+  //    default-terminate a cooperative child mid-flush, orphaning its nested
+  //    work. A child spawned without a stdin pipe skips straight to the wait.
+  child.stdin?.end()
+  if (await exitsWithin(child, graces.disposeEofGraceMs)) return
+  // 2. SIGTERM, escalating if the child still does not exit within the grace.
+  child.kill('SIGTERM')
+  if (await exitsWithin(child, graces.disposeGraceMs)) return
+  // 3. Force-kill and await the (now-certain) exit.
+  child.kill('SIGKILL')
+  await waitForExit(child)
+}
+
+/**
+ * A per-run config directory handle for an external CLI child — the target of
+ * `CLAUDE_CONFIG_DIR` / `CODEX_HOME`-style redirection. Hand {@link path} to
+ * the child's environment; call {@link remove} on dispose.
+ */
+export interface IsolatedConfigDir {
+  /** The directory to point the child at. */
+  path: string
+  /**
+   * Best-effort cleanup: removes the directory (recursively) iff this handle
+   * CREATED it — a pinned directory is never removed. Idempotent; never
+   * rejects (a leftover dir under the OS temp root is preferable to a failed
+   * dispose).
+   */
+  remove(): Promise<void>
+}
+
+/**
+ * An isolated config dir for one child run, so the child's behavior is a
+ * function of deployment config alone — never of whatever `~/.claude` /
+ * `~/.codex`-style state happens to exist on the host machine. Two modes:
+ *
+ * - no `pinnedPath` (the default): creates a FRESH private (0700) `mkdtemp`
+ *   dir under the OS temp root; {@link IsolatedConfigDir.remove} deletes it
+ *   best-effort;
+ * - `pinnedPath` set (a deployment deliberately sharing state across runs):
+ *   the pinned path is returned as-is — never created, never removed — the
+ *   deployment owns that directory's lifecycle.
+ *
+ * @param prefix - the `mkdtemp` name prefix for a fresh dir (e.g.
+ * `dsh-subagent-codex-`); ignored when `pinnedPath` is set.
+ * @param pinnedPath - a deployment-pinned directory to use instead of a
+ * fresh one.
+ * @returns the directory handle: `path` for the child env, `remove()` for
+ * dispose.
+ */
+export async function createIsolatedConfigDir(prefix: string, pinnedPath?: string): Promise<IsolatedConfigDir> {
+  if (pinnedPath !== undefined) {
+    return {
+      path: pinnedPath,
+      remove(): Promise<void> {
+        // A pinned dir is deployment-owned state (config the user asked to
+        // persist across runs); removing it here would destroy it. No-op.
+        return Promise.resolve()
+      },
+    }
+  }
+  const path = await mkdtemp(join(tmpdir(), prefix))
+  return {
+    path,
+    async remove(): Promise<void> {
+      try {
+        await rm(path, { recursive: true, force: true })
+      } catch {
+        // Best-effort by contract: swallows rm failures (EACCES/EBUSY-style —
+        // e.g. the dead child left an unreadable entry behind). The dir lives
+        // under the OS temp root, which reclaims it; failing dispose over
+        // cleanup would be worse than a leftover temp dir.
+      }
+    },
+  }
+}
@@ -0,0 +1,326 @@
+import { describe, expect, it, vi } from 'vitest'
+import { EventEmitter } from 'node:events'
+import { existsSync } from 'node:fs'
+import { mkdtemp, rm, stat, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import type { ChildProcess } from 'node:child_process'
+import {
+  buildChildEnv,
+  createIsolatedConfigDir,
+  disposeChildProcess,
+  exitsWithin,
+  SENSITIVE_ENV_PATTERN,
+  spawnFailure,
+  waitForExit,
+} from '../src/index.ts'
+
+// `rm` is wrapped (real-passthrough by default) so ONE test can inject a
+// rejection deterministically. A real recursive-rm failure is not portably
+// provokable — permission tricks (a chmod-000 subtree) fail only for
+// unprivileged users and are ignored by root — so this is the fs boundary
+// the testing policy sanctions mocking; everything else stays the real fs.
+vi.mock('node:fs/promises', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('node:fs/promises')>()
+  return { ...actual, rm: vi.fn(actual.rm) }
+})
+
+/**
+ * Unit tests for the shared out-of-process machinery. The env scrub and the
+ * isolated-config-dir helpers run against the REAL process env and REAL
+ * filesystem (one exception: the rm-failure path injects its rejection at the
+ * mocked fs boundary, see above); the exit waits and the dispose ladder run
+ * against a scriptable fake child so each escalation tier's timing is driven
+ * deterministically (the ACP backend's suite exercises the same ladder
+ * against real subprocesses end to end).
+ */
+
+/** What fells a scripted {@link FakeChild}. */
+type LethalTrigger = 'eof' | NodeJS.Signals
+
+/** Per-scenario script for a {@link FakeChild}. */
+interface FakeChildScript {
+  /**
+   * The one trigger that makes the child exit (SIGKILL always does,
+   * uncatchable, like a real process). Omitted: only SIGKILL fells it.
+   */
+  diesOn?: LethalTrigger
+  /** Delay (ms) between the lethal trigger and the exit event. */
+  delayMs?: number
+  /** `false` models a child spawned without a stdin pipe. */
+  stdin?: boolean
+}
+
+/**
+ * A scriptable stand-in for a ChildProcess carrying exactly the surface the
+ * helpers read: `exitCode`/`signalCode`, `stdin.end()`, `kill()`, and the
+ * `exit` event.
+ */
+class FakeChild extends EventEmitter {
+  exitCode: number | null = null
+  signalCode: NodeJS.Signals | null = null
+  readonly kills: NodeJS.Signals[] = []
+  stdinEnded = false
+  readonly stdin: { end: () => void } | null
+
+  constructor(private readonly script: FakeChildScript = {}) {
+    super()
+    this.stdin = script.stdin === false
+      ? null
+      : { end: () => { this.stdinEnded = true; this.maybeDie('eof') } }
+  }
+
+  kill(signal: NodeJS.Signals): boolean {
+    this.kills.push(signal)
+    this.maybeDie(signal)
+    return true
+  }
+
+  private maybeDie(trigger: LethalTrigger): void {
+    // SIGKILL is uncatchable — it always fells the child; any other trigger
+    // only when the scenario scripts it as the lethal one.
+    if (trigger !== 'SIGKILL' && this.script.diesOn !== trigger) return
+    setTimeout(() => {
+      if (trigger === 'eof') this.exitCode = 0
+      else this.signalCode = trigger
+      this.emit('exit', this.exitCode, this.signalCode)
+    }, this.script.delayMs ?? 0)
+  }
+}
+
+/** The helpers take a real ChildProcess; the fake carries the read surface. */
+function asChild(fake: FakeChild): ChildProcess {
+  return fake as unknown as ChildProcess
+}
+
+describe('buildChildEnv / SENSITIVE_ENV_PATTERN', () => {
+  it('drops credential-shaped ambient vars (KEY/SECRET/TOKEN, case-insensitive)', () => {
+    process.env.DSH_PROC_TEST_API_KEY = 'leak'
+    process.env.dsh_proc_test_secret = 'leak'
+    process.env.DSH_PROC_TEST_TOKEN = 'leak'
+    try {
+      const env = buildChildEnv({})
+      expect(env.DSH_PROC_TEST_API_KEY).toBeUndefined()
+      expect(env.dsh_proc_test_secret).toBeUndefined()
+      expect(env.DSH_PROC_TEST_TOKEN).toBeUndefined()
+    } finally {
+      delete process.env.DSH_PROC_TEST_API_KEY
+      delete process.env.dsh_proc_test_secret
+      delete process.env.DSH_PROC_TEST_TOKEN
+    }
+  })
+
+  it('forwards normal ambient vars', () => {
+    expect(SENSITIVE_ENV_PATTERN.test('PATH')).toBe(false)
+    expect(buildChildEnv({}).PATH).toBe(process.env.PATH)
+  })
+
+  it('layers extras AFTER the scrub, so a deliberate credential-shaped name survives', () => {
+    process.env.DSH_PROC_TEST_EXTRA_TOKEN = 'ambient-leak'
+    try {
+      const env = buildChildEnv({ DSH_PROC_TEST_EXTRA_TOKEN: 'explicit' })
+      // The ambient value was scrubbed; ONLY the explicit opt-in reaches the child.
+      expect(env.DSH_PROC_TEST_EXTRA_TOKEN).toBe('explicit')
+    } finally {
+      delete process.env.DSH_PROC_TEST_EXTRA_TOKEN
+    }
+  })
+
+  it('an extra overrides the ambient value of a non-credential var', () => {
+    process.env.DSH_PROC_TEST_PLAIN = 'ambient'
+    try {
+      expect(buildChildEnv({ DSH_PROC_TEST_PLAIN: 'override' }).DSH_PROC_TEST_PLAIN).toBe('override')
+    } finally {
+      delete process.env.DSH_PROC_TEST_PLAIN
+    }
+  })
+})
+
+describe('spawnFailure', () => {
+  it('resolves (never rejects) with the first error event', async () => {
+    const fake = new FakeChild()
+    const failure = spawnFailure(asChild(fake))
+    const err = new Error('spawn ENOENT')
+    fake.emit('error', err)
+    await expect(failure).resolves.toBe(err)
+  })
+
+  it('never settles for a child that spawns cleanly and exits', async () => {
+    const fake = new FakeChild({ diesOn: 'SIGTERM' })
+    const failure = spawnFailure(asChild(fake))
+    fake.kill('SIGTERM')
+    await waitForExit(asChild(fake))
+    // A clean lifecycle emits `exit`, never `error` — the capture stays
+    // pending forever, so a race against it is decided by the other arms.
+    const settled = await Promise.race([
+      failure.then(() => 'settled'),
+      new Promise<string>(resolve => setTimeout(() => { resolve('pending') }, 30)),
+    ])
+    expect(settled).toBe('pending')
+  })
+})
+
+describe('waitForExit / exitsWithin', () => {
+  it('resolves immediately for a child that already exited by code', async () => {
+    const fake = new FakeChild()
+    fake.exitCode = 0
+    await expect(waitForExit(asChild(fake))).resolves.toBeUndefined()
+  })
+
+  it('resolves immediately for a child that already died by signal', async () => {
+    const fake = new FakeChild()
+    fake.signalCode = 'SIGTERM'
+    await expect(waitForExit(asChild(fake))).resolves.toBeUndefined()
+  })
+
+  it('resolves on the exit event of a live child', async () => {
+    const fake = new FakeChild({ diesOn: 'SIGTERM', delayMs: 5 })
+    const exited = waitForExit(asChild(fake))
+    fake.kill('SIGTERM')
+    await expect(exited).resolves.toBeUndefined()
+    expect(fake.signalCode).toBe('SIGTERM')
+  })
+
+  it('exitsWithin resolves true immediately for an already-exited child (no listener attached)', async () => {
+    const fake = new FakeChild()
+    fake.exitCode = 0
+    await expect(exitsWithin(asChild(fake), 1000)).resolves.toBe(true)
+    expect(fake.listenerCount('exit')).toBe(0)
+  })
+
+  it('exitsWithin resolves true when the child exits inside the window', async () => {
+    const fake = new FakeChild({ diesOn: 'SIGTERM', delayMs: 5 })
+    fake.kill('SIGTERM')
+    await expect(exitsWithin(asChild(fake), 1000)).resolves.toBe(true)
+    // The once-listener fired and the grace timer was cleared — nothing lingers.
+    expect(fake.listenerCount('exit')).toBe(0)
+  })
+
+  it('exitsWithin resolves false on timeout for a child that never exits', async () => {
+    const fake = new FakeChild() // nothing short of SIGKILL fells it; no signal sent
+    await expect(exitsWithin(asChild(fake), 20)).resolves.toBe(false)
+    // The timeout arm removed its exit listener: repeated waits (a poll loop,
+    // the ladder's tiers) never accumulate listeners on the same child.
+    expect(fake.listenerCount('exit')).toBe(0)
+  })
+})
+
+describe('disposeChildProcess', () => {
+  it('returns immediately for an already-exited child (no EOF, no signals)', async () => {
+    const fake = new FakeChild()
+    fake.exitCode = 0
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 1000, disposeGraceMs: 1000 })
+    expect(fake.stdinEnded).toBe(false)
+    expect(fake.kills).toEqual([])
+  })
+
+  it('returns immediately for a child already dead by signal', async () => {
+    const fake = new FakeChild()
+    fake.signalCode = 'SIGKILL'
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 1000, disposeGraceMs: 1000 })
+    expect(fake.stdinEnded).toBe(false)
+    expect(fake.kills).toEqual([])
+  })
+
+  it('tier 1: a cooperative child quiesces on stdin EOF — no signal is ever sent', async () => {
+    const fake = new FakeChild({ diesOn: 'eof', delayMs: 5 })
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 1000, disposeGraceMs: 1000 })
+    expect(fake.stdinEnded).toBe(true)
+    expect(fake.kills).toEqual([])
+    expect(fake.exitCode).toBe(0)
+  })
+
+  it('tier 2: a child that ignores EOF but honors SIGTERM dies on the middle rung', async () => {
+    const fake = new FakeChild({ diesOn: 'SIGTERM', delayMs: 5 })
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 20, disposeGraceMs: 1000 })
+    expect(fake.stdinEnded).toBe(true)
+    expect(fake.kills).toEqual(['SIGTERM'])
+    expect(fake.signalCode).toBe('SIGTERM')
+  })
+
+  it('tier 3: a SIGTERM-trapping child is SIGKILLed, and dispose resolves only after the exit', async () => {
+    const fake = new FakeChild({ delayMs: 5 }) // only SIGKILL fells it
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 20, disposeGraceMs: 20 })
+    expect(fake.kills).toEqual(['SIGTERM', 'SIGKILL'])
+    // Quiescence, not a request: at resolution the child has ACTUALLY exited
+    // (the exit event landed, despite the scripted post-SIGKILL delay).
+    expect(fake.signalCode).toBe('SIGKILL')
+  })
+
+  it('walks the ladder for a child spawned without a stdin pipe', async () => {
+    const fake = new FakeChild({ stdin: false, diesOn: 'SIGTERM', delayMs: 5 })
+    await disposeChildProcess(asChild(fake), { disposeEofGraceMs: 20, disposeGraceMs: 1000 })
+    expect(fake.kills).toEqual(['SIGTERM'])
+  })
+})
+
+describe('createIsolatedConfigDir', () => {
+  it('creates a fresh private mkdtemp dir under the OS temp root', async () => {
+    const dir = await createIsolatedConfigDir('dsh-subagent-subprocess-test-')
+    try {
+      expect(dir.path.startsWith(join(tmpdir(), 'dsh-subagent-subprocess-test-'))).toBe(true)
+      const st = await stat(dir.path)
+      expect(st.isDirectory()).toBe(true)
+      // Private (0700) per the defensive-patterns temp-dir rule.
+      expect(st.mode & 0o777).toBe(0o700)
+    } finally {
+      await dir.remove()
+    }
+  })
+
+  it('creates a distinct dir per call (per-run isolation)', async () => {
+    const a = await createIsolatedConfigDir('dsh-subagent-subprocess-test-')
+    const b = await createIsolatedConfigDir('dsh-subagent-subprocess-test-')
+    try {
+      expect(a.path).not.toBe(b.path)
+    } finally {
+      await a.remove()
+      await b.remove()
+    }
+  })
+
+  it('remove() deletes a fresh dir recursively and is idempotent', async () => {
+    const dir = await createIsolatedConfigDir('dsh-subagent-subprocess-test-')
+    await writeFile(join(dir.path, 'settings.json'), '{}')
+    await dir.remove()
+    expect(existsSync(dir.path)).toBe(false)
+    // Second remove: nothing left to delete, still resolves.
+    await expect(dir.remove()).resolves.toBeUndefined()
+  })
+
+  it('returns a pinned dir verbatim and NEVER removes it', async () => {
+    const pinned = await mkdtemp(join(tmpdir(), 'dsh-subagent-subprocess-pinned-'))
+    try {
+      const dir = await createIsolatedConfigDir('ignored-prefix-', pinned)
+      expect(dir.path).toBe(pinned)
+      await dir.remove()
+      // The deployment owns a pinned dir's lifecycle — remove() must not touch it.
+      expect(existsSync(pinned)).toBe(true)
+    } finally {
+      await rm(pinned, { recursive: true, force: true })
+    }
+  })
+
+  it('does not create a missing pinned path (the deployment owns its lifecycle)', async () => {
+    const missing = join(tmpdir(), `dsh-subagent-subprocess-missing-${process.pid}`)
+    const dir = await createIsolatedConfigDir('ignored-prefix-', missing)
+    expect(dir.path).toBe(missing)
+    expect(existsSync(missing)).toBe(false)
+    await dir.remove()
+    expect(existsSync(missing)).toBe(false)
+  })
+
+  it('remove() is best-effort: an rm rejection resolves instead of rejecting', async () => {
+    const dir = await createIsolatedConfigDir('dsh-subagent-subprocess-locked-')
+    try {
+      // The swallow contract is error-kind agnostic; EACCES stands in for the
+      // family (EBUSY, a vanished mount, …) that best-effort must absorb.
+      vi.mocked(rm).mockRejectedValueOnce(Object.assign(new Error('EACCES: permission denied'), { code: 'EACCES' }))
+      await expect(dir.remove()).resolves.toBeUndefined()
+      // The injected rejection consumed the only rm call — nothing was deleted.
+      expect(existsSync(dir.path)).toBe(true)
+    } finally {
+      await rm(dir.path, { recursive: true, force: true })
+    }
+  })
+})
@@ -0,0 +1,11 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types"
+  },
+  "include": [
+    "src"
+  ],
+  "references": []
+}
@@ -6,7 +6,7 @@ Three layers, importable separately:

 - **`runScenario` (harness)** — boots the real agent bin as a subprocess via tsx (unbuilt, Loader path), drives it over ACP JSON-RPC stdio from a deterministic `input.json` script, tees raw stdout for the golden + purity check, and harvests every persisted session JSONL (parent + subagent children, primary-first) after a graceful stdin-EOF shutdown. Parameterized by `AgentUnderTest` (`binScript`, `configPath`, `tsconfigPath` — absolute paths; the subprocess cwd is a temp dir outside the repo).
 - **Normalizers** — pure functions turning the two captured surfaces into stable text: `normalizeStdout` (JSON-RPC ids → first-seen sequence; UUIDs/cwd → tokens; doubles as the stdout-purity check), `normalizeSessionLog` (times zeroed, `seq` kept), and the composable `scrubRequestHeaders` (header bulk → `{{system}}`/`{{tools}}`, structure kept — [pinned-header RFC](../../../docs/rfc/implemented/testing/2026-07-06-pin-request-header-content-in-one-scenario.md)).
- **`defineAcpSnapshotSuite` (factory)** — registers the whole describe/it tree for a scenario table: per-scenario golden + re-persisted-log compares, record-mode fixture write-back, the per-header-class pin with its live uniformity guard, and the fixture guard block (no orphan scenario dirs, required files present, exactly one pin per class, pinning fixtures well-formed, non-pinning fixtures header-scrubbed). Must be called at vitest collection time.
+- **`defineAcpSnapshotSuite` (factory)** — registers the whole describe/it tree for a scenario table: per-scenario golden + re-persisted-log compares, record/refresh fixture write-back, the per-header-class pin with its live uniformity guard, and the fixture guard block (no orphan scenario dirs, required files present, exactly one pin per class, pinning fixtures well-formed, non-pinning fixtures header-scrubbed). Must be called at vitest collection time.

 A consuming `*.snapshot.ts` is the scenario table plus one factory call:

@@ -27,12 +27,16 @@ defineAcpSnapshotSuite({
  },
  snapshotsDir: join(dirname(fileURLToPath(import.meta.url)), 'snapshots'),
  scenarios: SCENARIOS, // exactly one entry per header class sets pinsHeader
-  mode: process.env.DSH_SNAPSHOT === 'record' ? 'record' : 'replay',
+  mode: process.env.DSH_SNAPSHOT === 'record'
+    ? 'record'
+    : process.env.DSH_SNAPSHOT === 'refresh'
+      ? 'refresh'
+      : 'replay',
 })
 ```

 A scenario booting a differently-composed tree sets its own `configPath` (an overlay whose basename still ends in `cordis.yml`, so the bin's replay swap finds the sibling `*cordis.snapshot.yml`) and, when that composition changes the request header, its own `headerClass` with its own pinning scenario — the acp-agent example's Code Mode scenarios are the template.

-The example also ships a `cordis.snapshot.yml` replay overlay next to its `cordis.yml` (the bin swaps them under `DSH_SNAPSHOT=replay` — [single-source replay config RFC](../../../docs/rfc/implemented/testing/2026-07-04-single-source-acp-replay-config.md)); replay fixtures are served by [`dsh-llm-replay`](../llm-replay/README.md), which this package points at via the `DSH_SNAPSHOT_*` env vars it sets on the child. Fixture roles, record/replay semantics, and scenario-table fields are documented on `Scenario` and in the [snapshot RFC](../../../docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md).
+The example also ships a `cordis.snapshot.yml` replay overlay next to its `cordis.yml` (the bin swaps them under `DSH_SNAPSHOT=replay` — [single-source replay config RFC](../../../docs/rfc/implemented/testing/2026-07-04-single-source-acp-replay-config.md)); replay fixtures are served by [`dsh-llm-replay`](../llm-replay/README.md), which this package points at via the `DSH_SNAPSHOT_*` env vars it sets on the child. `pnpm run test:snapshot:record` calls the live LLM and rewrites the recorded scenarios' model fixtures; `pnpm run test:snapshot:refresh` stays keyless, runs the replay overlay, and rewrites stdout plus comparable session-log goldens from the committed model scripts. Fixture roles, record/replay/refresh semantics, and scenario-table fields are documented on `Scenario` and in the [snapshot RFC](../../../docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md).

 Constraints: `suite.ts` imports vitest, so the package is importable only inside a vitest run (the harness and normalizers have no such dependency but ship from the same entry). ACP-specific by design — the harness speaks the SDK's `ClientSideConnection`. Permission round-trips are scriptable: `InputScript.permissionAnswers` is a FIFO queue of option-kind selections (`allow_once`, `reject_once`, …) the client maps to the agent-issued `optionId` at answer time; an absent or exhausted queue answers `cancelled`, and a kind the request never offered rejects the run (the agent is answered `cancelled`, so a tolerant agent cannot absorb the scenario bug). Session config options are scriptable too: the `setConfigOption` step switches a knob over `session/set_config_option`, and `setConfigOptionExpectError` asserts the bridge rejects an unknown id or out-of-vocabulary value (the error frame stays in the transcript).
@@ -23,8 +23,11 @@
 *
 * `pnpm run test:snapshot:record` (DSH_SNAPSHOT=record + -u) re-records the
 * `session.jsonl` fixtures against the real API and refreshes the stdout golden
- * in one pass; the caller resolves that env into {@link SnapshotSuiteOptions}
- * (env reading stays at the suite edge, not in this library).
+ * in one pass. `pnpm run test:snapshot:refresh` (DSH_SNAPSHOT=refresh) instead
+ * replays the committed model scripts keylessly and writes the current stdout
+ * + persisted-log goldens back without calling a live LLM. The caller resolves
+ * that env into {@link SnapshotSuiteOptions} (env reading stays at the suite
+ * edge, not in this library).
 *
 * @module @deepseek-ai/dsh-acp-snapshot/suite
 */
@@ -133,12 +136,13 @@ export interface SnapshotSuiteOptions {
  /** The scenario table; exactly one entry must set `pinsHeader`. */
  scenarios: Scenario[]
  /**
-   * `replay` (keyless, the default tier) or `record` (live API; re-records the
-   * `recorded` scenarios' fixtures and refreshes the vitest goldens under
-   * `--update`). The caller derives this from `$DSH_SNAPSHOT` — env reading
-   * stays outside this library.
+   * `replay` (keyless, the default tier), `record` (live API; re-records the
+   * `recorded` scenarios' fixtures and refreshes the Vitest goldens under
+   * `--update`), or `refresh` (keyless replay that rewrites stdout goldens and
+   * comparable session fixtures from the replay run). The caller derives this
+   * from `$DSH_SNAPSHOT` — env reading stays outside this library.
   */
-  mode: 'replay' | 'record'
+  mode: 'replay' | 'record' | 'refresh'
 }

 /**
@@ -210,6 +214,86 @@ export function headerDeltaCount(rawLog: string): number {
    .length
 }

+/** A literal string replacement used to carry an existing fixture's volatile value into a refreshed log. */
+export interface FixtureReplacement {
+  /** The fresh replay-run value to replace. */
+  from: string
+  /** The existing fixture value to keep. */
+  to: string
+}
+
+function parseJsonlRecords(text: string): Record<string, unknown>[] {
+  return text.split('\n')
+    .filter(line => line.trim().length > 0)
+    .map(line => JSON.parse(line) as Record<string, unknown>)
+}
+
+/**
+ * Build the cross-log id/cwd replacements used by refresh write-back.
+ *
+ * @param logs The freshly harvested logs, in fixture order.
+ * @param fixtures The existing fixture contents, in matching order.
+ * @returns Literal replacements from fresh volatile values to the fixture's old values.
+ */
+export function refreshFixtureReplacements(logs: HarvestedLog[], fixtures: string[]): FixtureReplacement[] {
+  const replacements: FixtureReplacement[] = []
+  for (let i = 0; i < logs.length; i++) {
+    const fresh = parseJsonlRecords((logs[i] as HarvestedLog).content)[0]
+    const existing = parseJsonlRecords(fixtures[i] ?? '')[0]
+    for (const field of ['id', 'cwd'] as const) {
+      const from = fresh?.[field]
+      const to = existing?.[field]
+      if (typeof from === 'string' && typeof to === 'string' && from.length > 0 && from !== to) {
+        replacements.push({ from, to })
+      }
+    }
+  }
+  return replacements
+}
+
+function preserveFixtureVolatiles(record: Record<string, unknown>, existing: Record<string, unknown> | undefined): void {
+  if (existing === undefined || existing.type !== record.type) return
+  if (record.type === 'session') {
+    for (const field of ['id', 'createdAt', 'cwd', 'parentSession'] as const) {
+      if (field in record && field in existing) record[field] = existing[field]
+    }
+    return
+  }
+  if ('time' in record && 'time' in existing) record.time = existing.time
+  if (record.type !== 'hook/result') return
+  const data = record.data
+  const existingData = existing.data
+  if (
+    data !== null && typeof data === 'object'
+    && existingData !== null && typeof existingData === 'object'
+    && 'durationMs' in data && 'durationMs' in existingData
+  ) {
+    (data as Record<string, unknown>).durationMs = (existingData as Record<string, unknown>).durationMs
+  }
+}
+
+/**
+ * Rewrite a fresh replay-produced log so repeated refreshes do not churn
+ * volatile fixture fields. Meaningful event payloads come from `fresh`; the
+ * existing fixture lends session ids, cwd, creation times, event times, and
+ * hook durations where the record shape still matches.
+ *
+ * @param fresh The newly harvested session JSONL.
+ * @param existing The committed fixture JSONL being refreshed.
+ * @param replacements Cross-log literal replacements from {@link refreshFixtureReplacements}.
+ * @returns The stabilized JSONL content to write back.
+ */
+export function stabilizeRefreshLog(fresh: string, existing: string, replacements: FixtureReplacement[]): string {
+  let stable = fresh
+  for (const { from, to } of replacements) stable = stable.split(from).join(to)
+  const existingRecords = parseJsonlRecords(existing)
+  const records = parseJsonlRecords(stable)
+  for (let i = 0; i < records.length; i++) {
+    preserveFixtureVolatiles(records[i] as Record<string, unknown>, existingRecords[i])
+  }
+  return records.map(record => JSON.stringify(record)).join('\n') + '\n'
+}
+
 /**
 * Register the suite: one `describe` per scenario (the golden/log compares and
 * the header-uniformity guard) plus the fixture guard block (no orphan
@@ -224,6 +308,8 @@ export function headerDeltaCount(rawLog: string): number {
 export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
  const { agent, snapshotsDir, scenarios, mode } = options
  const RECORDING = mode === 'record'
+  const REFRESHING = mode === 'refresh'
+  const childMode: 'replay' | 'record' = RECORDING ? 'record' : 'replay'

  /** The class a scenario's header composition belongs to (see {@link Scenario.headerClass}). */
  const classOf = (scenario: Scenario): string => scenario.headerClass ?? 'default'
@@ -247,15 +333,18 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
    describe(`snapshot: ${scenario.name}`, () => {
      // In RECORD mode, only re-run the `recorded` (live-API) scenarios; the
      // `authored` ones (sidecar-driven errors/cancel) are never re-recorded.
+      // REFRESH mode is replay-backed and deterministic, so it runs every
+      // scenario and rewrites the comparable fixtures from that replay run.
      it.skipIf(RECORDING && !scenario.recorded)('matches the goldens', async () => {
        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')
        const workspaceDir = join(dir, 'workspace')
        const childSessions = scenario.childSessions ?? 0
+        const comparesLog = scenario.comparesLog ?? scenario.hasModelTurn
        const result = await runScenario(input, {
          agent,
-          mode,
+          mode: childMode,
          fixtureFile: join(dir, 'session.jsonl'),
          ...existsSync(overrideFile) ? { overrideFile } : {},
          // In REPLAY, forward the recorded child fixtures so each subagent session
@@ -280,30 +369,47 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
        }

        // RECORD mode (recorded model scenarios only): persist the freshly-harvested
-        // logs back to their fixtures — the primary to session.jsonl, each child to
-        // session.<n>.jsonl in harvest order. `--update` refreshes the Vitest
-        // goldens but NOT these fixtures, so write them here. A non-pinning
-        // scenario's fixtures are written header-scrubbed, so a re-record can
-        // never smuggle the full prompt/schema content back into every fixture.
+        // live logs back to their fixtures. REFRESH mode does the same from a
+        // keyless replay run for every comparable log, including authored
+        // scenarios that live record deliberately skips. The primary goes to
+        // session.jsonl, each child to session.<n>.jsonl in harvest order. A
+        // non-pinning scenario's fixtures are written header-scrubbed, so a
+        // re-record/refresh can never smuggle the full prompt/schema content
+        // back into every fixture.
        const scrub = scenario.pinsHeader === true
          ? (log: string): string => log
          : scrubRequestHeaders
-        if (RECORDING && scenario.recorded && scenario.hasModelTurn) {
-          expect(result.sessionLogs.length, 'record produced no session log to harvest').toBeGreaterThan(0)
+        const fixtureFiles = ['session.jsonl', ...Array.from({ length: childSessions }, (_, i) => `session.${i + 1}.jsonl`)]
+        const existingFixtures = REFRESHING
+          ? await Promise.all(fixtureFiles.map(file => readFile(join(dir, file), 'utf8')))
+          : []
+        const replacements = REFRESHING ? refreshFixtureReplacements(result.sessionLogs, existingFixtures) : []
+        const writesSessionFixtures = (RECORDING && scenario.recorded && scenario.hasModelTurn)
+          || (REFRESHING && comparesLog)
+        if (writesSessionFixtures) {
+          expect(result.sessionLogs.length, `${mode} produced no session log to harvest`).toBeGreaterThan(0)
          expect(result.sessionLogs.length, `expected ${childSessions + 1} session logs (parent + children)`)
            .toBe(childSessions + 1)
-          await writeFile(join(dir, 'session.jsonl'), scrub((result.sessionLogs[0] as HarvestedLog).content))
+          const primary = (result.sessionLogs[0] as HarvestedLog).content
+          await writeFile(join(dir, 'session.jsonl'), scrub(
+            REFRESHING ? stabilizeRefreshLog(primary, existingFixtures[0] as string, replacements) : primary,
+          ))
          for (let i = 1; i < result.sessionLogs.length; i++) {
-            await writeFile(join(dir, `session.${i}.jsonl`), scrub((result.sessionLogs[i] as HarvestedLog).content))
+            const child = (result.sessionLogs[i] as HarvestedLog).content
+            await writeFile(join(dir, `session.${i}.jsonl`), scrub(
+              REFRESHING ? stabilizeRefreshLog(child, existingFixtures[i] as string, replacements) : child,
+            ))
          }
        }

-        await expect(normalizeStdout(result.rawStdout, ctx))
-          .toMatchFileSnapshot(join(dir, 'stdout.golden.jsonl'))
+        const stdout = normalizeStdout(result.rawStdout, ctx)
+        if (REFRESHING) {
+          await writeFile(join(dir, 'stdout.golden.jsonl'), stdout)
+        }
+        await expect(stdout).toMatchFileSnapshot(join(dir, 'stdout.golden.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/*`).
-        const comparesLog = scenario.comparesLog ?? scenario.hasModelTurn
        if (comparesLog) {
          // The harvested logs (primary-first) must match their committed fixtures
          // 1:1. Each side passes through normalizeSessionLog, scrubbed against ITS
@@ -316,7 +422,6 @@ export function defineAcpSnapshotSuite(options: SnapshotSuiteOptions): void {
          // reason, and config, but not its bulk content (pinned once, in the
          // `pinsHeader` scenario).
          expect(result.sessionLogs.length, 'this scenario must persist a session log').toBe(childSessions + 1)
-          const fixtureFiles = ['session.jsonl', ...Array.from({ length: childSessions }, (_, i) => `session.${i + 1}.jsonl`)]
          for (let i = 0; i < fixtureFiles.length; i++) {
            const harvested = scrub((result.sessionLogs[i] as HarvestedLog).content)
            const fixture = scrub(await readFile(join(dir, fixtureFiles[i] as string), 'utf8'))
@@ -1,11 +1,18 @@
-import { cpSync, mkdtempSync } from 'node:fs'
+import { cpSync, mkdtempSync, readFileSync, writeFileSync } from 'node:fs'
 import { rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { afterAll, describe, expect, it } from 'vitest'
-import { defineAcpSnapshotSuite, type Scenario } from '../src/index.ts'
-import { childFixturePaths, fixtureContext, headerDeltaCount, normalizedHeaders } from '../src/suite.ts'
+import { defineAcpSnapshotSuite, type HarvestedLog, type Scenario } from '../src/index.ts'
+import {
+  childFixturePaths,
+  fixtureContext,
+  headerDeltaCount,
+  normalizedHeaders,
+  refreshFixtureReplacements,
+  stabilizeRefreshLog,
+} from '../src/suite.ts'

 /**
 * Unit tests for the suite factory, by running it: two synthetic suites over
@@ -55,16 +62,40 @@ const RECORD_SCENARIOS: Scenario[] = [
  { name: 'rec-skip', hasModelTurn: true, recorded: false, overridden: true },
 ]

-// Record mode mutates its snapshots dir, so run it on a throwaway copy —
-// except under the documented bootstrap knob, which regenerates the committed
-// fixtures/goldens in place.
+// Record/refresh modes mutate their snapshots dir, so run them on throwaway
+// copies — except record's documented bootstrap knob, which regenerates the
+// committed record fixtures/goldens in place.
 const BOOTSTRAP = process.env.ACP_SNAPSHOT_SPEC_BOOTSTRAP === '1'
 const recordDir = BOOTSTRAP ? RECORD_SRC : mkdtempSync(join(tmpdir(), 'acp-snap-record-suite-'))
 if (!BOOTSTRAP) cpSync(RECORD_SRC, recordDir, { recursive: true })
+const refreshDir = mkdtempSync(join(tmpdir(), 'acp-snap-refresh-suite-'))
+cpSync(REPLAY_DIR, refreshDir, { recursive: true })
+staleRefreshFixtures(refreshDir)
 afterAll(async () => {
  if (!BOOTSTRAP) await rm(recordDir, { recursive: true, force: true })
+  await rm(refreshDir, { recursive: true, force: true })
 })

+function staleRefreshFixtures(dir: string): void {
+  writeFileSync(join(dir, 'plain-turn', 'stdout.golden.jsonl'), 'stale stdout\n')
+
+  const plainBehaviorFile = join(dir, 'plain-turn', 'behavior.json')
+  const plainBehavior = JSON.parse(readFileSync(plainBehaviorFile, 'utf8')) as Record<string, unknown>
+  plainBehavior.echoEnv = true
+  writeFileSync(plainBehaviorFile, `${JSON.stringify(plainBehavior, null, 2)}\n`)
+
+  writeFileSync(join(dir, 'blocked-log', 'session.jsonl'), [
+    '{"type":"session","id":"99999999-8888-4777-8666-555555555555","createdAt":13,"cwd":"/rec/blocked-cwd"}',
+    '{"type":"hook/result","seq":1,"time":13,"data":{"decision":"stale","durationMs":99}}',
+    '',
+  ].join('\n'))
+  writeFileSync(join(dir, 'authored-error', 'session.jsonl'), [
+    '{"type":"session","id":"77777777-8888-4777-8666-555555555555","createdAt":13,"cwd":"/rec/error-cwd"}',
+    '{"type":"turn/end","seq":1,"time":9,"data":{"error":"stale"}}',
+    '',
+  ].join('\n'))
+}
+
 describe('defineAcpSnapshotSuite: replay mode', () => {
  defineAcpSnapshotSuite({ agent: AGENT, snapshotsDir: REPLAY_DIR, scenarios: REPLAY_SCENARIOS, mode: 'replay' })
 })
@@ -75,6 +106,27 @@ describe('defineAcpSnapshotSuite: record mode', () => {
  defineAcpSnapshotSuite({ agent: AGENT, snapshotsDir: recordDir, scenarios: RECORD_SCENARIOS, mode: 'record' })
 })

+describe('defineAcpSnapshotSuite: refresh mode', () => {
+  defineAcpSnapshotSuite({ agent: AGENT, snapshotsDir: refreshDir, scenarios: REPLAY_SCENARIOS, mode: 'refresh' })
+})
+
+describe('defineAcpSnapshotSuite: refresh write-back', () => {
+  it('rewrites stdout and comparable logs from a replay-mode child run', () => {
+    const stdout = readFileSync(join(refreshDir, 'plain-turn', 'stdout.golden.jsonl'), 'utf8')
+    expect(stdout).not.toContain('stale stdout')
+    expect(stdout).toContain('env:{\\"mode\\":\\"replay\\"')
+    expect(stdout).not.toContain('\\"mode\\":\\"refresh\\"')
+
+    const blocked = readFileSync(join(refreshDir, 'blocked-log', 'session.jsonl'), 'utf8')
+    expect(blocked).toContain('"decision":"block"')
+    expect(blocked).not.toContain('"decision":"stale"')
+
+    const authored = readFileSync(join(refreshDir, 'authored-error', 'session.jsonl'), 'utf8')
+    expect(authored).toContain('"error":"model exploded"')
+    expect(authored).not.toContain('"error":"stale"')
+  })
+})
+
 describe('defineAcpSnapshotSuite: registration contract', () => {
  it("throws when a scenario's header class has no pinning scenario", () => {
    expect(() => {
@@ -175,3 +227,56 @@ describe('headerDeltaCount', () => {
    expect(headerDeltaCount(`${other}\n`)).toBe(0)
  })
 })
+
+describe('refreshFixtureReplacements', () => {
+  it('maps fresh ids and cwd values to the existing fixture values, skipping non-replacements', () => {
+    const log = (content: string): HarvestedLog => ({ id: 'diagnostic', createdAt: 1, content })
+    const logs = [
+      log('{"type":"session","id":"","cwd":"/same"}\n'),
+      log('{"type":"session","id":"new-parent","cwd":"/new"}\n'),
+      log('{"type":"session","id":"new-child","cwd":"/new"}\n'),
+    ]
+    const fixtures = [
+      '{"type":"session","id":"","cwd":"/same"}\n',
+      '{"type":"session","id":"old-parent","cwd":"/old"}\n',
+    ]
+    expect(refreshFixtureReplacements(logs, fixtures)).toEqual([
+      { from: 'new-parent', to: 'old-parent' },
+      { from: '/new', to: '/old' },
+    ])
+  })
+})
+
+describe('stabilizeRefreshLog', () => {
+  it('keeps volatile fixture fields while preserving fresh meaningful payloads', () => {
+    const fresh = [
+      '{"type":"session","id":"new-child","createdAt":200,"cwd":"/new","parentSession":"new-parent","seedLength":1}',
+      '{"type":"hook/result","seq":1,"time":22,"data":{"decision":"block","durationMs":37}}',
+      '{"type":"turn/end","seq":2,"time":33,"data":{"error":"fresh error"}}',
+      '{"type":"tool/result","seq":3,"time":44,"data":{"text":"new-parent in /new"}}',
+      '{"type":"hook/result","seq":4,"time":55,"data":{"decision":"allow","durationMs":5}}',
+      '',
+    ].join('\n')
+    const existing = [
+      '{"type":"session","id":"old-child","createdAt":100,"cwd":"/old","parentSession":"old-parent","seedLength":5}',
+      '{"type":"hook/result","seq":1,"time":11,"data":{"decision":"stale","durationMs":99}}',
+      '{"type":"turn/end","seq":2,"data":{"error":"stale"}}',
+      '{"type":"assistant/message","seq":3,"time":12,"data":{"text":"different type"}}',
+      '{"type":"hook/result","seq":4,"time":13,"data":{"decision":"stale"}}',
+      '',
+    ].join('\n')
+
+    expect(stabilizeRefreshLog(fresh, existing, [
+      { from: 'new-parent', to: 'old-parent' },
+      { from: 'new-child', to: 'old-child' },
+      { from: '/new', to: '/old' },
+    ])).toBe([
+      '{"type":"session","id":"old-child","createdAt":100,"cwd":"/old","parentSession":"old-parent","seedLength":1}',
+      '{"type":"hook/result","seq":1,"time":11,"data":{"decision":"block","durationMs":99}}',
+      '{"type":"turn/end","seq":2,"time":33,"data":{"error":"fresh error"}}',
+      '{"type":"tool/result","seq":3,"time":44,"data":{"text":"old-parent in /old"}}',
+      '{"type":"hook/result","seq":4,"time":13,"data":{"decision":"allow","durationMs":5}}',
+      '',
+    ].join('\n'))
+  })
+})
@@ -15,6 +15,32 @@ function fakeParent(): Agent {
  return { id: AgentId('workflow-parent'), options: {} } as unknown as Agent
 }

+// Worker-thread startup is CPU-bound (a fresh thread compiles the runtime on
+// every start): on a contended CI runner it regularly blows past vitest's 5s
+// default test timeout, observed repeatedly on the coverage lane.
+vi.setConfig({ testTimeout: 30_000 })
+
+/**
+ * `vi.waitFor` with a contention-proof default timeout: the 1s default
+ * flaked repeatedly on the CI coverage lane, where worker-thread cold start
+ * (CPU-bound — a fresh thread compiles the runtime) competes with three
+ * sibling vitest workers for CPU. The 10s default is for exactly those
+ * races — waiting for a worker to start, run its first script line, or
+ * deliver an async child-registration message to the host. It is NOT for a
+ * wait that asserts the HOST reacted PROMPTLY to something that already
+ * happened (a settled result, an observed worker death): those keep an
+ * explicit tight override below, or the generous default would silently
+ * accept a multi-second regression in host-side reap latency as passing
+ * (proven by injecting a 6s delay into one such reap and watching the
+ * un-overridden version of this helper still pass in ~6s).
+ * @param assertion - retried until it stops throwing or the timeout elapses.
+ * @param timeout - override for a wait that must stay deliberately tight.
+ * @returns resolves when the assertion passes.
+ */
+function waitFor(assertion: () => void, timeout = 10_000): Promise<void> {
+  return vi.waitFor(assertion, { timeout, interval: 50 })
+}
+
 /** The vm-context escape hatch, spelled once: real Worker tests use it to make the WORKER misbehave. */
 const ESCAPE = "globalThis.constructor.constructor('return process')()"

@@ -316,7 +342,7 @@ describe('dsh-workflow-workerthread', () => {
      const runEnds: WorkflowResultInfo[] = []
      ctx.on('workflow/end', (_info, result) => { runEnds.push(result) })
      const handle = ctx.workflows.start({ ...scripted("return await agent('long job')"), parent })
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(1) })
+      await waitFor(() => { expect(provider.runs.length).toBe(1) })
      handle.cancel('user stopped it')
      const result = await handle.result
      expect(result.stopReason).toBe('cancelled')
@@ -357,7 +383,7 @@ describe('dsh-workflow-workerthread', () => {

      const controller = new AbortController()
      const second = ctx.workflows.start({ ...scripted("return await agent('job')"), parent, signal: controller.signal })
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(1) })
+      await waitFor(() => { expect(provider.runs.length).toBe(1) })
      controller.abort()
      expect((await second.result).stopReason).toBe('cancelled')
      await second.dispose()
@@ -400,7 +426,7 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent,
      })
-      await vi.waitFor(() => { expect(narration).toContain('started') })
+      await waitFor(() => { expect(narration).toContain('started') })
      handle.cancel('raced the completion')
      const result = await handle.result
      expect(result.stopReason).toBe('cancelled')
@@ -480,7 +506,7 @@ describe('dsh-workflow-workerthread', () => {
      })
      const result = await handle.result
      expect(result.stopReason).toBe('completed')
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(1) })
+      await waitFor(() => { expect(provider.runs.length).toBe(1) })
      await handle.dispose()
      // Not a waitFor: by the time dispose() returns, the slow child disposal
      // must already be complete (host-side registry quiescence).
@@ -525,8 +551,11 @@ describe('dsh-workflow-workerthread', () => {
      const result = await handle.result
      expect(result.stopReason).toBe('completed')
      // BEFORE dispose(): the settlement itself must have aborted the signal —
-      // without it this child would stay live until dispose's terminate.
-      await vi.waitFor(() => { expect(aborted).toEqual(['workflow settled']) })
+      // without it this child would stay live until dispose's terminate. This
+      // is a HOST-PROMPTNESS claim, not a cold-start race — a tight explicit
+      // bound (unlike the file default) so a multi-second reap regression
+      // cannot pass by outlasting the wait.
+      await waitFor(() => { expect(aborted).toEqual(['workflow settled']) }, 1000)
      await handle.dispose()
    })

@@ -572,9 +601,9 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent: fakeParent(),
      })
-      await vi.waitFor(() => { expect(starts).toBe(1) })
+      await waitFor(() => { expect(starts).toBe(1) })
      handle.cancel('stop now')
-      await vi.waitFor(() => { expect(cancelled).toEqual(['stop now']) }, { timeout: 800 })
+      await waitFor(() => { expect(cancelled).toEqual(['stop now']) }, 800)
      // The wedged worker's own completion loses to the in-flight cancel.
      const result = await handle.result
      expect(result.stopReason).toBe('cancelled')
@@ -602,7 +631,7 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent,
      })
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(1) }, { timeout: 10_000 })
+      await waitFor(() => { expect(provider.runs.length).toBe(1) })
      const before = Date.now()
      await handle.dispose()
      // Bounded by the grace (plus the terminate), never by the 1.5s spin.
@@ -625,7 +654,7 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent,
      })
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(1) }, { timeout: 10_000 })
+      await waitFor(() => { expect(provider.runs.length).toBe(1) })
      const handleDispose = handle.dispose()
      const result = await handle.result
      // The script itself settled (the wrapper's own dispose RPC found the
@@ -663,7 +692,7 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent,
      })
-      await vi.waitFor(() => { expect(order.filter(entry => entry.startsWith('start:')).length).toBe(2) }, { timeout: 10_000 })
+      await waitFor(() => { expect(order.filter(entry => entry.startsWith('start:')).length).toBe(2) })
      const fast = provider.runs.find(run => (run.request.prompt[0] as { text?: string }).text === 'fast')!
      fast.settle(text('fast done'))
      handle.cancel('stop now')
@@ -694,7 +723,7 @@ describe('dsh-workflow-workerthread', () => {
        ...scripted("await parallel([() => agent('a'), () => agent('b')])\nreturn 'unreachable'"),
        parent,
      })
-      await vi.waitFor(() => { expect(provider.runs.length).toBe(2) })
+      await waitFor(() => { expect(provider.runs.length).toBe(2) })
      handle.cancel('user stop')
      const result = await handle.result
      expect(result.stopReason).toBe('cancelled')
@@ -749,7 +778,9 @@ describe('dsh-workflow-workerthread', () => {
      // A worker death is a stop reason like any other: workflow/end fires
      // with the error outcome — for a bus observer it is the only obituary.
      expect(runEnds).toEqual([{ stopReason: 'error', error: result.error, agentsStarted: 1 }])
-      await vi.waitFor(() => { expect(cancelled.length).toBe(1) })
+      // Result already settled — this is the reap's promptness, not a
+      // cold-start race; tight explicit bound (see the helper's doc comment).
+      await waitFor(() => { expect(cancelled.length).toBe(1) }, 1000)
      await handle.dispose()
    }, 15_000)

@@ -770,10 +801,12 @@ describe('dsh-workflow-workerthread', () => {
      expect(result.stopReason).toBe('error')
      expect(result.error).toContain('worker blew up')
      // The reap wound the stray child down (cancel + a CLEAN dispose).
-      await vi.waitFor(() => {
+      // Result already settled — this is the reap's promptness, not a
+      // cold-start race; tight explicit bound (see the helper's doc comment).
+      await waitFor(() => {
        expect(provider.runs.length).toBe(1)
        expect(provider.runs[0]!.disposed).toBe(true)
-      })
+      }, 1000)
      await handle.dispose()
    }, 15_000)

@@ -802,7 +835,7 @@ describe('dsh-workflow-workerthread', () => {
        `),
        parent,
      })
-      await vi.waitFor(() => { expect(order.filter(entry => entry.startsWith('start:')).length).toBe(2) })
+      await waitFor(() => { expect(order.filter(entry => entry.startsWith('start:')).length).toBe(2) })
      const fast = provider.runs.find(run => (run.request.prompt[0] as { text?: string }).text === 'fast')!
      fast.settle(text('fast done'))
      const result = await handle.result
@@ -837,7 +870,10 @@ describe('dsh-workflow-workerthread', () => {
      const result = await handle.result
      expect(result.stopReason).toBe('error')
      expect(result.error).toContain('exit code 5')
-      await vi.waitFor(() => { expect(provider.runs[0]!.disposed).toBe(true) })
+      // Result already settled — this is the reap's promptness (bounded
+      // above the mock's fixed 300ms dispose delay, not a cold-start race);
+      // tight explicit bound (see the helper's doc comment).
+      await waitFor(() => { expect(provider.runs[0]!.disposed).toBe(true) }, 1000)
      await handle.dispose()
    }, 15_000)

@@ -855,7 +891,7 @@ describe('dsh-workflow-workerthread', () => {
      })
      const logs: string[] = []
      ctx.on('workflow/log', (_info, message) => { logs.push(message) })
-      await vi.waitFor(() => { expect(logs).toContain('armed') })
+      await waitFor(() => { expect(logs).toContain('armed') })
      handle.cancel('stop it')
      // The grace is deliberately huge: only the worker's own death (exit 3,
      // unreachable by the cancel — the script ignores hooks) settles this.
@@ -781,6 +781,9 @@ importers:
      '@deepseek-ai/dsh-subagent':
        specifier: workspace:^
        version: link:../subagent
+      '@deepseek-ai/dsh-subagent-subprocess':
+        specifier: workspace:^
+        version: link:../subagent-subprocess
      cordis:
        specifier: ^4.0.0-rc.6
        version: 4.0.0-rc.6(@cordisjs/plugin-include@1.0.4)(@cordisjs/plugin-loader@1.0.0-rc.4)
@@ -910,6 +913,12 @@ importers:
        specifier: ^4.0.0-rc.6
        version: 4.0.0-rc.6(@cordisjs/plugin-include@1.0.4)(@cordisjs/plugin-loader@1.0.0-rc.4)

+  packages/subagent/subagent-subprocess:
+    devDependencies:
+      cordis:
+        specifier: ^4.0.0-rc.6
+        version: 4.0.0-rc.6(@cordisjs/plugin-include@1.0.4)(@cordisjs/plugin-loader@1.0.0-rc.4)
+
  packages/subagent/tool-subagent:
    dependencies:
      schemastery:
@@ -59,6 +59,7 @@
    { "path": "./packages/support/subagent-mock" },
    { "path": "./packages/subagent/tool-subagent" },
    { "path": "./packages/subagent/subagent-inprocess" },
+    { "path": "./packages/subagent/subagent-subprocess" },
    { "path": "./packages/subagent/subagent-spawn" },
    { "path": "./packages/subagent/subagent-fork" },
    { "path": "./packages/subagent/subagent-acp" },
@@ -70,6 +70,7 @@
    { "path": "./packages/support/subagent-mock" },
    { "path": "./packages/subagent/tool-subagent" },
    { "path": "./packages/subagent/subagent-inprocess" },
+    { "path": "./packages/subagent/subagent-subprocess" },
    { "path": "./packages/subagent/subagent-spawn" },
    { "path": "./packages/subagent/subagent-fork" },
    { "path": "./packages/subagent/subagent-acp" },
@@ -7,10 +7,14 @@ import { defineConfig } from 'vitest/config'
 // normalized stdout transcript + re-persisted log against committed goldens.
 // `pnpm run test:snapshot:record` (DSH_SNAPSHOT=record + -u) re-records the
 // fixtures against the real API and refreshes the goldens.
+// `pnpm run test:snapshot:refresh` (DSH_SNAPSHOT=refresh) stays keyless: it
+// replays the committed model scripts and writes the current stdout/log goldens
+// without calling the live LLM.
 //
 // Replay loads no .env (it must never reach the network — a recorded fixture
-// drives the model). Record reads DEEPSEEK_API_KEY from the env or a gitignored
-// repo-root .env, so a contributor with a key only in .env can still record.
+// drives the model), and refresh uses that same keyless replay path. Record
+// reads DEEPSEEK_API_KEY from the env or a gitignored repo-root .env, so a
+// contributor with a key only in .env can still record.
 if (process.env.DSH_SNAPSHOT === 'record') {
  try {
    process.loadEnvFile(new URL('.env', import.meta.url).pathname)