Circleci Builds Skill for Codex

CircleCI Builds

Overview

Use this skill to turn failing CircleCI pipelines into actionable fixes with clear evidence. Prioritize fast root-cause isolation, minimal safe patches, and explicit validation criteria.

Read references/transient-vs-deterministic.md when deciding whether a failure should be fixed in code/config, retried, mitigated with rerun behavior, or reported as external/transient.

Read ../config/references/test-results-and-splitting.md when the failure involves missing test metadata, flaky test reruns, test splitting, or JUnit XML setup.

Inputs To Gather

• Failing pipeline/workflow/job identifier
• Branch and commit SHA
• First failing step and key log lines
• Whether rerun on same commit reproduces failure

Workflow

• Identify the primary failing signal.
• Record the first failing job and step, not every downstream failure.
• Classify issue type.
• Config syntax/reference issue
• Environment/toolchain mismatch
• Dependency/cache issue
• Test or build regression
• External/transient failure
• Apply the smallest viable fix.
• Patch only files tied to confirmed root cause.
• Keep workaround scope narrow.
• Validate.
• Run highest-signal local checks when possible.
• Define expected CircleCI success signals for the rerun.
• Report residual risk.
• Call out unverified assumptions and likely follow-up checks.

Guardrails

• Do not hide deterministic failures with blanket retries.
• Avoid mixing unrelated refactors into incident fixes.
• Treat external service outages as report-and-mitigate unless user asks for deeper redesign.
• Keep confidence levels explicit when logs are incomplete.
• Do not recommend automatic reruns or flaky-test workflows until the failure is classified as plausibly transient.

Output Contract

Provide:

• Failure summary (pipeline/workflow/job/step).
• Root-cause hypothesis with confidence.
• Applied changes with file list.
• Validation plan and expected pass signal.
• Remaining risk.