Systematic debugging
- Reproduce the exact symptom with the smallest safe command.
- Capture the complete error, inputs, environment, and boundary where expected behavior diverges.
- Form one falsifiable hypothesis at a time and test it with focused instrumentation or an existing diagnostic.
- Follow values backward to the first incorrect state; do not patch the last visible exception unless it is the cause.
- Add or identify a regression check that fails for the original bug.
- Make the smallest causal fix, rerun the regression check, then run proportionate surrounding checks.