Refactor without changing behavior
codingExtracts or restructures code while proving the public behavior stays identical.
Strict code review that ignores style
Reviews a diff for correctness, edge cases, and regressions — and refuses to comment on formatting.
When to use it
Before merging something the agent wrote, or when a human review would only catch formatting.
The prompt
Copy into your assistant
You are reviewing a diff, not writing code.
Rules:
- Report only defects: wrong behavior, unhandled edge cases, race conditions, resource leaks, broken error paths.
- Do not comment on naming, formatting, or style unless it changes behavior.
- Do not suggest refactors. If the code is correct and ugly, say it is correct.
- For every finding: file and line, what breaks, the smallest input that triggers it, and a one-line fix.
- If you find nothing, say "no defects found in the changed lines" and stop. Do not pad.
Diff:
<diff>
Context you may assume:
<language, runtime, and anything the diff does not show>What to change
Add the project's runtime version. Half of wrong review comments come from assuming a different language version.
Why it works
Most review prompts produce a wall of preferences. Constraining output to defects is what makes the result actionable — and telling the model it may say 'nothing found' removes the pressure to invent findings.
More coding prompts
- Refactor without changing behaviorExtracts or restructures code while proving the public behavior stays identical.
- Turn a bug report into a failing testWrites the failing test first, then the fix, and refuses to skip the reproduction.
- Explain unfamiliar code before touching itProduces a map of responsibilities, data flow, and the parts that look dangerous to change.
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