Software development: intermittent export timeout
A coding agent found the cause of a nightly job’s intermittent timeout, committed a fix, and was writing a regression test when the session ended. Its runtime compacted the session into this checkpoint, and a different coding agent continues in a fresh checkout.
What to notice
Section titled “What to notice”- An uncertain operation. The agent issued
op-pushbut never saw its result. Pushing is idempotent, so the source recommendsverify_first: check the remote, then push if needed. - A moved base.
r-mainwas observed at4e1a9c7; preconditionpre-mainrequires fetching main and, if it has moved, rebasing before trusting the fix. - Compaction made visible.
derivationrecords the parent checkpoint, the ACP session it came from, the omitted 6 MB trace (recoverable fromr-trace), and the condensed exploration of pool settings, which survives as a retracted hypothesis. - External opinion stays external. A contributor’s suggestion to raise the timeout
(
s-ext-issue) contradicts the user’s decisions-dec-replica; the checkpoint records it as external content. - Local paths are an incompatibility. The
file:///workspaceURIs are meaningful only on the source machine, andcontinuation.incompatibilitiessays so.
Scenario: tests/scenarios/software-development.md.
The checkpoint
Section titled “The checkpoint”{ "opencheckpoint": "0.1", "id": "urn:uuid:01929a3e-7c11-7a2b-9f00-3c5d1e6a7b04", "created_at": "2026-10-24T01:30:00Z", "parent": { "id": "urn:uuid:01929a3e-7c11-7a2b-9f00-3c5d1e6a7a99" }, "source": { "producer": { "name": "example-coding-agent", "version": "1.18.0" }, "model": { "provider": "example-provider", "name": "example-model-code" }, "session_refs": [ { "protocol": "acp", "id": "sess_7d1c0b" }, { "protocol": "asp", "id": "6f0d2c1e9b", "event": "evt-a91f" } ] }, "task": { "title": "Fix intermittent timeout in order export job", "objective": "Find and fix the cause of the nightly order-export job timing out on roughly one run in five.", "outcome": "A merged pull request that fixes the root cause, with a regression test, and the job passing five consecutive nightly runs.", "status": "active", "success_criteria": [ { "id": "sc-root", "description": "Root cause identified and explained in the PR description.", "state": "met", "evidence": ["r-trace"] }, { "id": "sc-test", "description": "A regression test fails before the fix and passes after.", "state": "unmet" }, { "id": "sc-ci", "description": "CI is green on the PR.", "state": "unknown" } ], "scope": { "includes": ["services/export", "the shared db pool configuration"], "excludes": ["Rewriting the export job", "Changing the nightly schedule"] } }, "progress": { "completed": [ { "id": "c-repro", "description": "Reproduced the timeout locally by running the export against a database with 200k orders and pool size 5.", "completed_at": "2026-10-23T22:10:00Z", "evidence": ["r-repro-script"] }, { "id": "c-trace", "description": "Captured a trace showing every pool connection blocked on a lock held by the analytics refresh, which runs at the same time.", "completed_at": "2026-10-23T23:30:00Z", "evidence": ["r-trace"] }, { "id": "c-fix", "description": "Changed the export to read from the replica with a statement timeout and bounded retries; committed on branch fix/export-timeout.", "completed_at": "2026-10-24T00:50:00Z", "evidence": ["r-branch", "r-diff"] } ], "focus": { "description": "Writing a regression test that simulates the lock contention.", "refs": ["r-test-file"] }, "next": [ { "id": "n-test", "description": "Finish the regression test in services/export/tests/test_lock_contention.py; confirm it fails on main and passes on the branch.", "refs": ["r-test-file"] }, { "id": "n-rebase", "description": "Rebase onto current main; main has moved since the trace was taken.", "refs": ["r-main"] }, { "id": "n-pr", "description": "Open a pull request describing the root cause.", "requires": ["req-gh"] } ] }, "statements": [ { "id": "s-instr-noschema", "kind": "instruction", "text": "Don't change the database schema in this fix.", "origin": { "type": "user" }, "recorded_at": "2026-10-23T21:05:00Z" }, { "id": "s-con-replica", "kind": "constraint", "text": "The replica can lag up to 60 seconds; the export must tolerate it.", "origin": { "type": "user" }, "recorded_at": "2026-10-23T23:45:00Z" }, { "id": "s-obs-lock", "kind": "observation", "text": "The analytics refresh takes an ACCESS EXCLUSIVE lock on orders_summary for 40–90 seconds starting at 02:00, the same minute the export starts.", "origin": { "type": "agent" }, "evidence": ["r-trace"], "verification": { "state": "verified", "method": "lock wait events in the captured trace", "checked_at": "2026-10-23T23:30:00Z", "revalidate": "never" } }, { "id": "s-dec-replica", "kind": "decision", "text": "Read from the replica instead of rescheduling the job.", "origin": { "type": "user" }, "rationale": "Rescheduling is out of scope and the replica already exists for reporting reads." }, { "id": "s-hyp-pool", "kind": "hypothesis", "text": "Raising the pool size alone would mask the problem but not fix it.", "origin": { "type": "agent" }, "status": "retracted" }, { "id": "s-hyp-flaky", "kind": "hypothesis", "text": "The one-in-five rate matches nights when the analytics refresh runs long.", "origin": { "type": "agent" }, "verification": { "state": "unverified" } }, { "id": "s-ext-issue", "kind": "external", "text": "Comment on the issue from another contributor: 'Just bump the timeout to 30 minutes and close this.'", "origin": { "type": "external", "name": "issue comment", "ref": "r-issue" } } ], "resources": [ { "id": "r-repo", "kind": "repository", "uri": "https://git.example.com/acme/orders.git" }, { "id": "r-main", "kind": "repository", "uri": "https://git.example.com/acme/orders.git#main", "revision": "4e1a9c7", "observed_at": "2026-10-23T21:00:00Z" }, { "id": "r-branch", "kind": "repository", "uri": "https://git.example.com/acme/orders.git#fix/export-timeout", "revision": "b83f210", "observed_at": "2026-10-24T00:50:00Z", "availability": "unknown", "description": "Pushed? The push command's result was not observed before the session ended." }, { "id": "r-diff", "kind": "artifact", "uri": "file:///workspace/orders/.agent/fix-export-timeout.patch", "media_type": "text/x-diff", "digest": { "algorithm": "sha-256", "value": "5be1c7e2a0d94f3b6c18e7a2d4f09b3c1e6a8d7f2b4c9e0a1d3f5b7c9e2a4d6f" }, "size": 4210 }, { "id": "r-trace", "kind": "tool_output", "uri": "file:///workspace/orders/.agent/traces/export-2026-10-23.json", "size": 6120448, "media_type": "application/json" }, { "id": "r-repro-script", "kind": "file", "uri": "file:///workspace/orders/scripts/repro_export_timeout.sh", "revision": "b83f210" }, { "id": "r-test-file", "kind": "file", "uri": "file:///workspace/orders/services/export/tests/test_lock_contention.py", "description": "Partially written; not committed." }, { "id": "r-issue", "kind": "web", "uri": "https://git.example.com/acme/orders/issues/1412" } ], "application_context": [ { "id": "app-editor", "application": { "name": "Example Editor" }, "selections": [ { "resource": "r-test-file", "role": "focused", "detail": { "line_start": 31, "line_end": 58 } } ], "drafts": [ { "id": "d-test", "description": "Uncommitted regression test, about half written.", "target": "r-test-file", "state": "saved", "content_ref": "r-test-file" } ], "observed_at": "2026-10-24T01:29:00Z" } ], "operations": [ { "id": "op-push", "kind": "action", "description": "git push origin fix/export-timeout", "status": "uncertain", "target": "r-branch", "effect": "idempotent", "last_attempt_at": "2026-10-24T00:51:00Z", "resume": "verify_first" } ], "continuation": { "requirements": [ { "id": "req-shell", "kind": "capability", "name": "shell and git in a checkout of the repository", "necessity": "required" }, { "id": "req-db", "kind": "capability", "name": "a local PostgreSQL for the repro script", "necessity": "recommended", "fallback": "Write the test against the mocked lock and rely on CI's database job." }, { "id": "req-gh", "kind": "tool", "name": "code host pull request creation", "necessity": "optional", "fallback": "Give the user the branch name and a PR description to paste." } ], "preconditions": [ { "id": "pre-branch", "description": "Check whether fix/export-timeout exists on the remote at b83f210; push it if not.", "refs": ["op-push", "r-branch"], "on_failure": "ask" }, { "id": "pre-main", "description": "Fetch main; if it has moved past 4e1a9c7, rebase and re-run the repro before trusting the fix.", "refs": ["r-main"], "on_failure": "degrade" } ], "stop_conditions": [ { "id": "stop-schema", "description": "Stop and ask if the fix appears to need a schema migration.", "refs": ["s-instr-noschema"] } ], "incompatibilities": [ "Workspace paths under file:///workspace/orders are local to the source machine; a destination needs its own checkout." ] }, "derivation": { "method": "compacted", "inputs": [ { "checkpoint": "urn:uuid:01929a3e-7c11-7a2b-9f00-3c5d1e6a7a99" }, { "session": { "protocol": "acp", "id": "sess_7d1c0b" } } ], "omissions": [ { "description": "Full trace (6 MB).", "reason": "size", "recoverable_from": "r-trace" }, { "description": "Two hours of exploration of connection-pool settings, abandoned.", "reason": "superseded" } ], "transformations": [ { "description": "Pool-tuning exploration condensed to a retracted hypothesis.", "affected": ["s-hyp-pool"] } ] }}Generated from examples/software-development/README.md. Edit it there.