mirror of
https://github.com/paperclipai/paperclip.git
synced 2026-10-22 00:30:19 +02:00
Devin Foley
c7f4bc1300
## Thinking Path > - Paperclip is the open source app people use to manage AI agents for work > - Agents on remote sandbox targets reach the Paperclip API through the sandbox callback bridge: a loopback gateway inside the sandbox writes request files, and a host-side worker polls them over the provider's exec channel and forwards them to the server > - The worker's poll loop had one terminal catch: a single reset or slow exec ended the relay for the rest of the run > - The in-sandbox gateway kept queueing requests against the dead worker, so every later API call from the agent stranded, including its final status write > - A relay that dies on one transient fault turns a routine provider hiccup into a lost issue disposition > - This pull request restructures the loop so transient faults back off and retry, while the watchdog remains the escalation path for sustained outages > - The benefit is that one flaky exec no longer severs an agent from the control plane mid-run ## Linked Issues or Issue Description Refs #9904. Refs #8977. Both touch adjacent bridge behavior (curl shim, header forwarding); neither addresses worker-loop lifetime. No public issue exists for this defect. The description below follows the bug report template. **What happened?** During a staging run, the host-side bridge worker hit one failed sandbox exec while relaying requests. The poll loop's only catch is terminal: it failed the pending requests and set the worker to settled, with no restart. The agent's later API calls saw connection-level failures or bridge errors until the run ended. Its final `PATCH status: done` was lost, and the missing-disposition recovery had to repair the issue in a corrective run. **Expected behavior** One transient exec failure must not end the relay for the rest of the run. The worker must back off and retry. A sustained outage must still fail queued requests fast through the watchdog. In-flight request semantics (abort plus 504 backstop, retry-safe 503) must not change. **Steps to reproduce** 1. Start a remote-sandbox run and let the provider exec channel reject or stall one call while the bridge worker polls. 2. The worker hits one `listJsonFiles` failure or one request-attempt timeout, and the loop exits through its terminal catch. 3. Every later bridge request strands. The loopback gateway keeps accepting requests that never complete, and after 64 queued files it answers every request with 503 until run end. ## What Changed - `startSandboxCallbackBridgeWorker`'s poll loop now separates three failure domains: - A failed poll backs off exponentially (capped at 5 s) and retries instead of dying. The first failure of a streak still lands on the run trace through the workerFailed span; later repeats only warn. - A failed or hung request attempt runs the same recovery pass the loop previously died on — abort the in-flight handler (its 504 backstop keeps the caller from stranding) and 503 the unclaimed queued requests — and the loop then continues and serves the caller's retry. - A listing where every file already has an in-flight attempt sleeps one poll interval, like an empty listing. The previous immediate re-list was a hot spin: an exec storm against a real channel, and a pure-microtask loop that starved every timer in the process when the queue client resolves synchronously. - The watchdog, the claim/finalize fences, and the stop/drain semantics are unchanged. ## Verification - `npx vitest run packages/adapter-utils/src/sandbox-callback-bridge.test.ts` — 38 passed. - New regression test: a request queued behind three consecutive poll failures is still delivered. - Updated tests: the stalled-poll test now expects recovery (the handler's real 200) instead of a terminal 503; the sustained-outage 503 path remains proven by the dedicated watchdog test; the recovery-503-write-retry test triggers the recovery pass through a hung request read, because a hung poll no longer runs that pass. - `pnpm --filter @paperclipai/adapter-utils typecheck`. ## Risks - Behavior change: a transiently failing poll no longer mass-fails queued requests on the first error. Callers wait through the backoff window, bounded by the existing in-sandbox 30 s response deadline, or the watchdog fails them after 20 s of no successful iteration. This trades fast-but-terminal degradation for recovery. - A hard-down channel now retries every ≤5 s for the rest of the run instead of stopping. Each retry is one exec attempt against a channel that already fails. - In-flight mutation safety is unchanged: the guard map and the claim protocol still prevent a double-applied host mutation, and a guarded file is always finalized by its own attempt or by its 504 backstop. ## Model Used - Claude Fable 5 (Anthropic), model id `claude-fable-5`, extended thinking enabled, agentic tool use via Claude Code (CLI harness), 200k context window. ## 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