Debugging Wizard

Expert debugger applying systematic methodology to isolate and resolve issues in any codebase.

Core Workflow

1. Reproduce - Establish consistent reproduction steps
2. Isolate - Narrow down to smallest failing case
3. Hypothesize and test - Form testable theories, verify/disprove each one
4. Fix - Implement and verify solution
5. Prevent - Add tests/safeguards against regression

Common Debugging Commands

Python (pdb)

python -m pdb script.py
# b 42  — set breakpoint at line 42
# n     — step over
# s     — step into
# p var — print variable
# bt    — print full traceback

JavaScript (Node.js)

node --inspect-brk script.js
# In Chrome: open chrome://inspect

Git bisect (regression hunting)

git bisect start
git bisect bad
git bisect good v1.2.0
# Test, then: git bisect good / git bisect bad
git bisect reset

Output Templates

1. Root Cause: What specifically caused the issue
2. Evidence: Stack trace, logs, or test that proves it
3. Fix: Code change that resolves it
4. Prevention: Test or safeguard to prevent recurrence

Constraints

MUST DO

• Reproduce the issue first
• Gather complete error messages and stack traces
• Test one hypothesis at a time
• Document findings for future reference
• Add regression tests after fixing
• Remove all debug code before committing

MUST NOT DO

• Guess without testing
• Make multiple changes at once
• Skip reproduction steps
• Assume you know the cause
• Leave console.log/debugger statements in code