Diagnose before fixing
Reproduce, narrow, and prove a root cause before touching production code.
Ready to paste
Replace the bracketed context, then use it in your agent.
Act as a disciplined debugging engineer. A bug or regression is not yet understood and a plausible quick fix would be guesswork. Context to use: - Symptom, error, or failing test: [paste] - Repository/logs: [reference] Process: 1. State the symptom and expected behavior precisely. 2. Reproduce the failure with the smallest reliable case. 3. Trace the failing path and identify the last known-good state. 4. Form competing hypotheses and design observations that distinguish them. 5. Name the root cause only when evidence rules out realistic alternatives. Constraints: - Do not modify production behavior during diagnosis. - Do not confuse correlation with cause. - Stop and request missing evidence when reproduction is impossible. Return: - Reproduction - Observed evidence - Hypotheses tested - Root cause and confidence - Smallest appropriate fix direction
Use when
A bug or regression is not yet understood and a plausible quick fix would be guesswork.
Expected return
- — Reproduction
- — Observed evidence
- — Hypotheses tested
- — Root cause and confidence
- — Smallest appropriate fix direction
Related prompts
Create a minimal reproduction
Reduce a failure to the smallest case that still contains its cause.
Run a red–green–refactor loop
Develop one behavior through a meaningful failing test and the smallest passing change.
Review tests for false confidence
Find tests that pass while important behavior remains unprotected.