CI Debugger
Goal
Find the first meaningful CI failure, explain the root cause with evidence, propose the smallest fix, and recommend the validation command that should prevent recurrence.
When to use
- A CI, build, deploy, or package-manager job failed.
- The user provides logs, a run URL, or asks to inspect CI live.
- Long logs need targeted extraction instead of full dumping.
When not to use
- The user asks for broad repo health rather than one failed pipeline.
- The failure requires production incident response beyond CI diagnosis.
- The user wants dependency risk review without a failing job; use
dependency-update-review.
Inputs
- CI provider, workflow/job name, run URL, failed step, and logs.
- Package manager output, build artifacts, test reports, and recent diffs.
- Repo scripts, workflow YAML, and environment requirements.
Inputs to inspect
- Inspect the failed step, first meaningful error, relevant workflow config, package scripts, and changed files.
- Use targeted log excerpts instead of dumping full logs.
Process
- Identify the failed job and failed step.
- Extract the first meaningful error, not the last cascade.
- Search logs with targeted patterns and inspect nearby context.
- Map the failure to code, config, dependency, environment, or infra.
- Propose a minimal fix and a regression validation command.
- Avoid broad rewrites unless the failure proves a systemic issue.
Workflow
Follow the process above and verify the minimal fix locally when possible. Report skipped live CI checks explicitly.
Decision points
- If logs are incomplete, ask for the failed step or run URL.
- If credentials or external services are required, separate local validation from live validation.
- If multiple jobs fail, group by shared root cause before fixing each.
Safety rules
- Do not paste full secrets from logs.
- Do not rerun expensive or write-capable workflows without approval.
- Do not assume downstream failures are separate bugs until the first failure is resolved.
References
Read references/ci-log-reading.md when logs are noisy or very large.
Scripts
No bundled scripts.
Output format
Return:
- Failing job and step
- First meaningful error
- Root cause
- Minimal fix
- Validation command
- Remaining risks
Failure modes
- If logs are missing, request the failed step output or run URL.
- If authentication is needed for live logs, provide local reproduction steps.
- If multiple roots are plausible, rank them by evidence.
Completion criteria
- Root cause is tied to log evidence.
- Proposed fix is scoped to the failure.
- Validation path is explicit.
1---2name: ci-debugger3description: Diagnose failed CI jobs and build pipelines using small-log, evidence-first debugging. Use when the user shares a failed GitHub Actions, GitLab CI, Vercel, or package-manager build and wants root cause, minimal fix, and regression test guidance.4license: Apache-2.05---67# CI Debugger89## Goal1011Find the first meaningful CI failure, explain the root cause with evidence, propose the smallest fix, and recommend the validation command that should prevent recurrence.1213## When to use1415- A CI, build, deploy, or package-manager job failed.16- The user provides logs, a run URL, or asks to inspect CI live.17- Long logs need targeted extraction instead of full dumping.1819## When not to use2021- The user asks for broad repo health rather than one failed pipeline.22- The failure requires production incident response beyond CI diagnosis.23- The user wants dependency risk review without a failing job; use `dependency-update-review`.2425## Inputs2627- CI provider, workflow/job name, run URL, failed step, and logs.28- Package manager output, build artifacts, test reports, and recent diffs.29- Repo scripts, workflow YAML, and environment requirements.3031## Inputs to inspect3233- Inspect the failed step, first meaningful error, relevant workflow config, package scripts, and changed files.34- Use targeted log excerpts instead of dumping full logs.3536## Process37381. Identify the failed job and failed step.392. Extract the first meaningful error, not the last cascade.403. Search logs with targeted patterns and inspect nearby context.414. Map the failure to code, config, dependency, environment, or infra.425. Propose a minimal fix and a regression validation command.436. Avoid broad rewrites unless the failure proves a systemic issue.4445## Workflow4647Follow the process above and verify the minimal fix locally when possible. Report skipped live CI checks explicitly.4849## Decision points5051- If logs are incomplete, ask for the failed step or run URL.52- If credentials or external services are required, separate local validation from live validation.53- If multiple jobs fail, group by shared root cause before fixing each.5455## Safety rules5657- Do not paste full secrets from logs.58- Do not rerun expensive or write-capable workflows without approval.59- Do not assume downstream failures are separate bugs until the first failure is resolved.6061## References6263Read `references/ci-log-reading.md` when logs are noisy or very large.6465## Scripts6667No bundled scripts.6869## Output format7071Return:72731. Failing job and step742. First meaningful error753. Root cause764. Minimal fix775. Validation command786. Remaining risks7980## Failure modes8182- If logs are missing, request the failed step output or run URL.83- If authentication is needed for live logs, provide local reproduction steps.84- If multiple roots are plausible, rank them by evidence.8586## Completion criteria8788- Root cause is tied to log evidence.89- Proposed fix is scoped to the failure.90- Validation path is explicit.