/debug

description: Systematic debugging — 4-phase root cause process with defense-in-depth verification
argument-hint: "<bug description or error message>"

/debug — Systematic Debugging

4-phase systematic debugging: reproduce → isolate → fix → verify with defense-in-depth.

Invocation

/debug TypeError: Cannot read property 'id' of undefined
/debug Login page shows blank after OAuth redirect

Workflow

Step 1: Reproduce

Apply **cm-debugging** skill: 1. Understand the error context 2. Reproduce the issue reliably 3. Identify the exact conditions

Step 2: Root Cause Analysis

5-phase investigation: 1. **Observe** — Read error logs, stack traces 2. **Hypothesize** — Form 2-3 possible causes 3. **Test** — Write a test that reproduces the bug 4. **Isolate** — Narrow down to exact root cause 5. **Verify** — Confirm the root cause with evidence

Step 3: Fix with TDD

1. Write a failing test that exposes the bug 2. Fix the code minimally 3. Confirm the test passes 4. Run full test suite to check for regressions

Step 4: Defense-in-Depth

• Add error handling for similar cases
• Update documentation if needed
• Record learning in CONTINUITY.md

Step 5: Suggest Next

• "Fixed? → `/review` to verify the fix"
• "Need broader changes? → `/plan`"