## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work.
> - The Paperclip runner needs a safe boundary before it can launch
ACP-compatible agents.
> - A caller-controlled command, model, environment, or frame could
bypass that boundary.
> - The ACPX transport contract in #12386 defines the allowed messages
but does not bind a runtime profile.
> - This pull request defines closed, versioned profiles and validates
the launch inputs around that contract.
> - The benefit is a small and reviewable trust boundary before any ACPX
process can become available.
## Linked Issues or Issue Description
**Agent or provider**
ACPX sidecar support for the qualified Pi, Claude, and Codex ACP
servers.
**Why this adapter is useful**
The runner needs one bounded process boundary for ACP-compatible
providers. A closed profile prevents an untrusted run from selecting an
arbitrary executable, package version, or model.
**How the agent is invoked**
A later pull request will launch an internal sidecar from an exact
profile. This pull request only validates profiles, environment values,
and protocol frames. It does not add an executable dependency or enable
an adapter.
**Additional context**
This pull request is stacked on #12386. It keeps the existing direct
adapters and the Codex runner path unchanged.
## What Changed
- Add a closed profile table for the qualified Pi, Claude, and Codex ACP
servers.
- Require the exact qualified model and return an isolated profile value
to callers.
- Add an agent-specific environment allowlist with entry and aggregate
size limits.
- Add strict parsing for bounded sidecar requests and structured plan
values.
- Reject unknown fields, unsupported protocol versions, invalid
identifiers, null bytes, cyclic values, and oversized input.
## Verification
- Runner TypeScript typecheck — passed.
- Runner TypeScript tests — 40 files and 362 Vitest tests passed; 11
Node contract tests passed.
- `pnpm -r typecheck` — passed for all applicable workspaces.
- `pnpm build` — passed, including runner binary, server, UI, and
workspace packages.
- Prettier and `git diff --check` — passed.
- The diff contains 6 files and does not change `pnpm-lock.yaml`, a
workflow, a package dependency, or a public export.
## Risks
The main risk is accepting more launch state than the sidecar needs. The
implementation uses an agent-specific allowlist, rejects null bytes, and
enforces per-entry and aggregate bounds. This pull request does not
launch a process or expose a new adapter, so production and
direct-adapter behavior remain unchanged.
## Model Used
OpenAI Codex with GPT-5 and repository tool use.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either linked an existing public item or described the
issue in this PR
- [x] I have not referenced internal or instance-local Paperclip issues
or links
- [x] My branch name describes the change and contains no internal task
identifier
- [x] I have run the affected tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have documented the compatibility and security boundary
- [ ] All applicable GitHub Actions are green
- [ ] Greptile is 5/5 with every actionable comment resolved
- [x] I will address all review findings before requesting merge
## Thinking Path
> - Paperclip is the open source control plane people use to manage AI
agents for work.
> - Local agent heartbeats need durable process identity so the server
can supervise them.
> - The ACPX runtime owns the child process used by `codex_local`
sessions.
> - ACPX did not expose the child PID and start time to the Paperclip
adapter.
> - Warm ACPX runtimes can also serve a later heartbeat without a new
spawn event.
> - A hot restart could therefore classify a live Codex run as lost
because its heartbeat row had no process identity.
> - This pull request forwards ACPX spawn identity, reuses it for
compatible warm heartbeats, and fails closed when identity cannot be
persisted.
> - The benefit is reliable hot-restart adoption for eligible local
Codex runs.
## Linked Issues or Issue Description
No matching public GitHub issue was found.
**What happened?**
A `codex_local` heartbeat could run through ACPX without a persisted
`processPid` or `processStartedAt`. A Paperclip hot restart then had no
durable identity for the live ACP child. Recovery could classify the run
as `process_lost` even while the child was still alive.
**Expected behavior**
ACPX reports the real child PID and start time before the first prompt.
A compatible warm runtime reports the same known identity to each later
heartbeat that reuses the child. ACPX stops the child if the identity is
invalid or persistence fails. Hot-restart recovery can then adopt the
live run.
**Steps to reproduce**
1. Start a `codex_local` heartbeat through the ACPX execution lane.
2. Keep the run active during a Paperclip hot restart.
3. Inspect the heartbeat row before this change.
4. Observe that the process identity can be null and recovery cannot
adopt the live child.
**Reproduced on**
- Paperclip `master` before this change.
- Linux source deployment.
- `codex_local` with ACPX `0.12.0`.
## What Changed
- Add an awaited `onAgentSpawn` lifecycle hook to the patched ACPX
runtime.
- Forward the ACP child PID and start time through the adapter `onSpawn`
callback.
- Keep a mutable callback sink for cached runtimes so a later respawn
updates the current heartbeat.
- Reuse the last known process identity when a compatible warm heartbeat
reuses the existing child.
- Kill the ACP child and fail session startup when the PID is invalid or
identity persistence rejects.
- Add ACPX and heartbeat recovery tests for callback ordering, warm
reuse, failure cleanup, durable row identity, and hot-restart adoption.
- Document the one-time drain required when an installed pre-fix run
already lacks process metadata.
## Verification
-
`PAPERCLIP_HOME="$PAPERCLIP_RUN_SCRATCH_DIR/test-home-execute-escalated"
pnpm exec vitest run
packages/adapter-utils/src/acpx-engine/execute.test.ts` — 89 passed.
-
`PAPERCLIP_HOME="$PAPERCLIP_RUN_SCRATCH_DIR/test-home-recovery-escalated"
pnpm exec vitest run
server/src/__tests__/heartbeat-process-recovery.test.ts` — 92 passed.
-
`PAPERCLIP_HOME="$PAPERCLIP_RUN_SCRATCH_DIR/test-home-remote-smoke-escalated"
pnpm exec vitest run
packages/adapter-utils/src/acpx-engine/remote-spawn-smoke.test.ts` — 3
passed.
-
`PAPERCLIP_HOME="$PAPERCLIP_RUN_SCRATCH_DIR/test-home-ci-repro-escalated"
pnpm exec vitest run
server/src/__tests__/heartbeat-dependency-scheduling.test.ts` — 6
passed.
- `pnpm --filter @paperclipai/adapter-utils typecheck` — passed.
- Reverse and forward dry-run application of `patches/acpx@0.12.0.patch`
— passed.
- `git diff --check` — passed.
- `git diff --exit-code origin/master...HEAD -- pnpm-lock.yaml` —
passed.
- `git diff --exit-code origin/master...HEAD -- .github/workflows` —
passed.
## Risks
- Runtime risk is low to moderate. ACPX now awaits process-identity
persistence during child startup.
- ACPX kills the child when persistence fails. This prevents an
unsupervised process, but it makes that heartbeat fail visibly.
- A compatible warm heartbeat reuses the identity of the existing ACP
child. Regression tests verify that identity is persisted before the
next prompt.
- The change updates the vendored ACPX patch. Package installation must
apply that patch.
- There are no schema, migration, public API, UI, workflow, or lockfile
changes.
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- OpenAI Codex used GPT-5.3-Codex for the earlier implementation.
- OpenAI Codex used GPT-5 for the lifecycle-hook revision and the
current fail-closed review fix. The runtime did not expose a more
specific snapshot ID or context-window size. Both runs used reasoning,
repository tools, and code execution.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
## Thinking Path
> - Paperclip is the open source app people use to manage AI agents for
work
> - Local Claude, Codex, Gemini, and custom ACP adapters run through the
shared embedded ACPX engine
> - That engine wrapped every local agent command in a generated Bash
script to inject environment variables and filter child stderr
> - Windows cannot directly spawn that Bash wrapper, and npm/pnpm ACP
binaries are exposed through `.cmd` shims there
> - ACPX 0.12 already supports per-session child environment variables,
so the wrapper is unnecessary
> - This pull request registers agent commands directly, injects env
through ACPX session options, captures child stderr in-process, and adds
a real Node ACP spawn smoke on Ubuntu and Windows
> - The benefit is one cross-platform spawn path with a reusable smoke
test instead of parallel shell-wrapper implementations
## Linked Issues or Issue Description
Fixes#9941.
Refs #9428 and #9771.
**What happened**
ACPX-backed local agents failed to start on Windows because Paperclip
registered a generated POSIX `.sh` wrapper as the agent command. Windows
also needs the `.cmd` npm/pnpm shim when resolving built-in ACP
binaries, and symlink creation can fail with `EPERM` for seeded
auth/skill files.
**Expected behavior**
The same ACPX engine path should spawn a real ACP agent on Windows and
Linux, forward Paperclip/runtime env without mutating `process.env`,
preserve filtered/unfiltered child stderr behavior, and fall back to
copies where Windows symlinks are unavailable.
**Steps to reproduce**
Run a local ACPX adapter on Windows with the prior wrapper path. ACPX
attempts to spawn the generated `.sh` file and the agent never
initializes.
**Deployment mode**
Local Paperclip adapters using
`packages/adapter-utils/src/acpx-engine/`.
## What Changed
- Removed generated Bash agent/env wrappers and registered local
commands directly with ACPX.
- Passed the resolved child environment through ACPX
`sessionOptions.env`, including resume retry paths.
- Added a minimal `acpx@0.12.0` package patch exposing child stderr
callbacks and allowing documented uppercase env-map keys in persisted
session options.
- Moved stderr tee/filter behavior in-process: raw stderr remains in the
per-run file while benign `nes/close` noise is omitted from live stderr.
- Preferred `.cmd` ancestor binaries on Windows and added `EPERM` copy
fallbacks for Codex auth seeding and Gemini skill materialization.
- Added a real Node ACP echo-agent spawn smoke that can run directly on
any supported platform.
## Verification
- `pnpm exec vitest run
packages/adapter-utils/src/acpx-engine/execute.test.ts
packages/adapter-utils/src/acpx-engine/spawn-smoke.test.ts` — 57 passed.
- `pnpm --filter @paperclipai/adapter-utils typecheck` — passed.
- `node --test scripts/acpx-patch-packaging.test.mjs
scripts/release-lib.test.mjs` — 10 passed.
- Full canary release dry run under Node 24.18.0 / npm 11.16.0 — passed
in an isolated scratch clone.
- `git diff --check` — passed during implementation verification.
- One-time GitHub Actions proof: [Ubuntu ACPX spawn
smoke](https://github.com/paperclipai/paperclip/actions/runs/29924348927/job/88937774579),
[Windows ACPX spawn
smoke](https://github.com/paperclipai/paperclip/actions/runs/29924348927/job/88937774558),
and [Canary Dry
Run](https://github.com/paperclipai/paperclip/actions/runs/29924348927/job/88937774497)
passed on head `f345ac69f2`; the dedicated smoke jobs are intentionally
not retained in the recurring PR workflow.
## Risks
- The ACPX stderr callback and env persistence exemption are carried as
a pnpm dependency patch until ACPX exposes/fixes those behaviors
upstream.
- Child stderr is synchronously appended to preserve ordering and
failure diagnostics; unusually high-volume agent stderr could briefly
block the Node event loop.
- The Windows-specific `.cmd` resolution and symlink `EPERM` branches
are proven by the standalone smoke test and the linked one-time
`windows-latest` run rather than a permanent CI gate.
> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.
## Model Used
- OpenAI GPT-5.4 via Codex CLI, medium reasoning, repository/tool
execution enabled; context-window size is not exposed in this session.
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
---------
Co-authored-by: Paperclip <noreply@paperclip.ing>
Dotta
Nicky Leach