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PATTERN Cited by 1 source

Reproduce to regression-test agent skill

Intent

Turn an externally reported defect into an executable regression test before selecting and applying a repair. The test converts a one-off reproduction into a durable acceptance criterion for both the candidate patch and later changes.

Flow

  1. Clone or otherwise obtain the reporter’s reproduction.
  2. Reproduce the behavior in a controlled environment.
  3. Instrument and diagnose the relevant code path.
  4. Verify whether the observed behavior is truly a defect rather than intended behavior.
  5. Express the reproduction as a failing unit test.
  6. Implement a repair and require the new test plus relevant existing tests to pass.

Astro exposes this sequence as the core of a reusable issue-triage skill. (Source: sources/2026-08-04-cloudflare-astro-issue-triage)

Why it matters

A patch can satisfy a narrative issue description while missing its actual trigger or introducing a regression. The test anchors the repair to executable evidence and is especially useful when a bot later revisits the same code path. Astro’s HMR example shows the other side: missing tests allowed a locally plausible edit to cause regressions elsewhere. (Source: sources/2026-08-04-cloudflare-astro-issue-triage)

Limits

A reporter’s reproduction can be incomplete, environment-specific, or security-sensitive. Passing a new unit test does not establish release compatibility, performance, or cross-version correctness; it should compose with review, broader CI, and where appropriate a preview-release validation gate.

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