[WIP] Investigate CI failure due to fuzz job cancellation

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<issue_title>[CI Failure Doctor] CI Failure Doctor - Run 22396700002: fuzz job cancelled by concurrency</issue_title>
<issue_description>### CI Failure Investigation - Run github/gh-aw#37830

Summary

The fuzz job for run 37830 (commit 6867b8113f22940a4c3ebfffdfb1f99830ea1523) was terminated midway through the sequential fuzz targets because GitHub Actions’ cancel-in-progress concurrency guard kicked in when a newer CI workflow (run 37832) started on the same branch. The job never reported any test errors—only a cancellation message—so no defects were introduced by the commit itself.

Failure Details

• Run: 22396700002
• Commit: 6867b8113f22940a4c3ebfffdfb1f99830ea1523
• Trigger: push (main)

Root Cause Analysis

The fuzz job defines a concurrency group named ci-$\{\{ github.ref }}-fuzz with cancel-in-progress: true, so when run 37832 (sha 38ab34435fb7c33057d7a1935f21e490ba350e82) spun up at 2026-02-25T12:26:52Z, GitHub Actions automatically cancelled the earlier run (37830) while it was still executing FuzzExpandLabelTriggerShorthand. The job logs end with ##[error]The operation was canceled. at 2026-02-25T12:28:07Z, and no fuzz test reported an unexpected failure prior to cancellation.

Failed Jobs and Errors

• fuzz (ubuntu-latest, job Run fuzz tests step): ##[error]The operation was canceled. while executing FuzzExpandLabelTriggerShorthand after completing 17 of the 24 queued fuzz targets. No assertions or module downloads failed.

Investigation Findings

• Run 22396700002 (run number 37830) spent ~4½ minutes running sequential fuzz targets before being cancelled; the log shows every earlier target completing successfully and the cancellation happening immediately after the 17th fuzz
• The concurrency definition in .github/workflows/ci.yml intentionally prevents overlapping fuzz jobs by cancelling prior runs, so the cancellation is the expected behavior when another push lands on main
• Subsequent runs confirm the pattern: run 37832 (sha 38ab3443…) started at 12:26:52Z, run 37833 was cancelled shortly afterwards, and run 37834 is currently in progress, which is why the older run 37830 could not finish

Recommended Actions

• Re-run the CI workflow for commit 6867b8113f22940a4c3ebfffdfb1f99830ea1523 if the fuzz results from that specific commit are still needed; the job had not failed, it was merely cancelled by the concurrency guard.
• Only adjust the concurrency guard if you want to allow multiple overlapping fuzz runs on main; otherwise the existing cancel-in-progress setting is doing what it should and no code change is required.

Prevention Strategies

Because the fuzz job runs a long series of sequential targets, it will always be cancelled when a newer push lands while it is still running; the best way to avoid these log entries is to let the latest run finish (no human action needed) or schedule the fuzz suite behind a manual gate. Re-running the workflow on the same commit will produce the full results.

AI Team Self-Improvement

Before concluding that the fuzz job itself is broken, check for additional workflow runs in the same concurrency group and verify whether a ##[error]The operation was canceled. message lines up with cancel-in-progress being triggered; that will prevent misclassifying expected cancellations as regressions.

Historical Context

• The CI workflow is currently on run 37834 for 92baa35c… and run 37833 was itself cancelled, showing that the queue is active and newer pushes displace older builds
• The cancellation log for run 37830 is consistent with previously recorded concurrency cancellations (e.g., run 37832 also terminated early, run 37829 failed for a different reason)

🩺 Diagnosis provided by CI Failure Doctor

To install this workflow, run gh aw add githubnext/agentics/workflows/ci-doctor.md@ea350161ad5dcc9624cf510f134c6a9e39a6f94d. View source at https://github.com/githubnext/agentics/tree/ea350161ad5dcc9624cf510f134c6a9e39a6f94d/workflows/ci-doctor.md.

• expires on Feb 26, 2026, 12:35 PM UTC

Comments on the Issue (you are @copilot in this section)

• Fixes [CI Failure Doctor] CI Failure Doctor - Run 22396700002: fuzz job cancelled by concurrency #18334

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