Strict code review that ignores style
codingReviews a diff for correctness, edge cases, and regressions — and refuses to comment on formatting.
Turn a bug report into a failing test
Writes the failing test first, then the fix, and refuses to skip the reproduction.
When to use it
When a bug report arrives without a reproduction and you want the fix to be provable.
The prompt
Copy into your assistant
Given a bug report, produce a regression test before any fix.
Steps, in order:
1. Restate the bug as a single sentence about observable behavior.
2. List the input conditions that must be true for the bug to appear.
3. Write the smallest failing test that captures those conditions. It must fail on the current code and pass only when fixed.
4. Only then propose the fix.
If the report is ambiguous, ask exactly one clarifying question and stop. Do not guess at the reproduction.
Bug report:
<report>
Relevant code:
<code>
Test framework:
<framework>What to change
Name the test framework and version. Without it the model writes jest-style mocks for a vitest project and the test never runs.
Why it works
The instruction to stop and ask one question is the important part: a wrong reproduction is worse than no fix, because it launders a guess into a passing test.
More coding prompts
- Explain unfamiliar code before touching itProduces a map of responsibilities, data flow, and the parts that look dangerous to change.
- Question to SQL, with the assumptions spelled outTurns a business question into a query plus the schema assumptions it made.
- Review an API design before you build itPressure-tests an endpoint spec for naming, pagination, errors, and the version you will regret in a year.
Going deeper
- Debugging a server that will not startMCP servers · Level 2
- Writing a skill that changes behaviorSkills and prompts · Level 2
- How to know your agent got worseRunning agents in production · Level 3