kb-debugging

name	kb-debugging
description	Domain logic for systematic debugging — injected into the debugger agent. Provides common bug patterns and debugging tools reference. Not invoked directly.
user-invocable	false
disable-model-invocation	true

Debugging Reference

Supplementary reference for the debugger agent. The core scientific debugging process (Reproduce → Evidence → Hypothesize → Test → Fix → Verify) is defined in the agent itself — this skill provides pattern recognition and tooling guidance.

Common Bug Patterns

Off-by-One Errors

• Check loop boundaries, array indices, fence-post conditions
• Look for < vs <=, i vs i+1

Null/Undefined References

• Trace the variable back to its origin
• Check all paths — is there a code path where it's never assigned?
• Look for async gaps where state can change

Race Conditions

• Look for shared mutable state accessed from multiple threads/goroutines/processes
• Check for missing locks, atomic operations, or synchronization
• Add ordering guarantees or make state immutable

State Management

• Check if state is being mutated where it shouldn't be
• Look for stale closures, cached values, or shallow copies
• Verify state transitions are valid

Integration Issues

• Check API contracts — is the caller sending what the callee expects?
• Verify serialization/deserialization (JSON types, date formats, encoding)
• Check network timeouts, retries, and error handling

Debugging Tools

• Logging — Add targeted, temporary log statements at key decision points
• Debugger — Set breakpoints at suspicious locations, inspect state
• Git bisect — Find the exact commit that introduced the bug
• Profiler — For performance bugs, identify bottlenecks
• Network tools — For API issues, inspect request/response payloads

Additional Resources

Reference Files

• references/debugging-tools.md — Language-specific debuggers, profilers, and diagnostic tools
• references/common-errors.md — Common error patterns by language and framework