name: debugging
description: Root cause analysis and debugging protocols. Use when encountering errors, test failures, unexpected behavior, stack traces, or when code behaves differently than expected.

Debugging

Systematic approach to root cause analysis and debugging.

When to Use

• Encountering errors or exceptions
• Test failures that need investigation
• Unexpected behavior in code
• Stack traces or error messages
• Code behaving differently than expected
• Performance issues or bugs

Core Principles

• Evidence-based: Base diagnosis on error messages, logs, and reproducible steps
• Systematic: Follow structured debugging process
• Minimal fixes: Implement smallest change that resolves issue
• Verify solutions: Confirm fix works and doesn't introduce regressions

Debugging Process

Follow systematic debugging process:
1. Capture error information (message, stack trace, logs, environment)
2. Identify reproduction steps (minimal steps, conditions, edge cases)
3. Isolate failure location (function/module, recent changes, dependencies)
4. Form and test hypotheses (evidence-based, systematic testing, debug logging)
5. Implement minimal fix (smallest change, preserve behavior, follow patterns)
6. Verify solution (issue resolved, no regressions, tests pass)

See references/root-cause-analysis.md for detailed methods.

Strategic Debug Logging

Add debug logging to entry/exit points, state transitions, conditional branches, external API calls, and data transformations. Remove after issue resolved unless it provides ongoing value.

Error Pattern Recognition

Common patterns: null/undefined errors, type errors, timing issues, state corruption, configuration issues. See references/error-patterns.md for detailed patterns and solutions.

Integration

After fixing:
- Verify CI passes (types, tests, lint)
- Stage atomic changes (fix + tests)
- Suggest semantic commit message
- Confirm with user before committing

References

For detailed guidance, see:
- references/root-cause-analysis.md - Systematic analysis methods
- references/error-patterns.md - Common error patterns and solutions
- references/debugging-tools.md - Debugging tools and techniques