Debug

/debug - Systematic Debugging Workflow

Structured approach to debugging issues.

Usage

/debug <error message or description>
/debug --trace                # Include stack trace analysis
/debug --bisect               # Git bisect guidance

What This Skill Does

1. Understand the Problem - Parse error, reproduce issue
2. Form Hypotheses - Likely causes based on error type
3. Systematic Investigation - Step-by-step debugging
4. Identify Root Cause - Narrow down to exact issue
5. Propose Fix - Solution with verification

Debugging Framework

# Debug Session: [Issue Description]

## 1. Problem Statement
**Error**: [Exact error message]
**When**: [When does it occur]
**Frequency**: [Always / Sometimes / Once]

## 2. Reproduction Steps
1. Step 1
2. Step 2
3. Error occurs

**Minimal Reproduction**:
```python
# Smallest code that reproduces the issue

3. Initial Hypotheses

4. Investigation Log

Test 1: [Hypothesis being tested]

Action: What I did Result: What happened Conclusion: Confirmed / Ruled out

Test 2: ...

5. Root Cause

[Exact cause identified]

6. Fix

# Before
problematic_code()

# After
fixed_code()

7. Verification

• Fix applied
• Original issue resolved
• No regression introduced
• Test added to prevent recurrence

## Common Error Patterns

### Python
| Error | Common Causes |
|-------|---------------|
| `AttributeError` | None value, wrong type, typo |
| `KeyError` | Missing dict key, wrong key name |
| `ImportError` | Missing dep, circular import, wrong path |
| `TypeError` | Wrong arg type, wrong arg count |
| `ValueError` | Invalid value, parsing error |

### Rust
| Error | Common Causes |
|-------|---------------|
| `unwrap() panic` | None/Err not handled |
| `borrow checker` | Ownership, lifetime issues |
| `type mismatch` | Generic constraints, conversions |

## Debugging Commands

```bash
# Python with debugger
python -m pdb script.py

# Python with verbose imports
python -v script.py

# Rust with backtrace
RUST_BACKTRACE=1 cargo run

# Git bisect
git bisect start
git bisect bad HEAD
git bisect good v1.0.0

Instructions for Claude

When /debug is invoked:

1. Parse the error - Extract error type, message, location
2. Ask for context - Reproduction steps, when it started
3. Form hypotheses - Rank by likelihood
4. Test systematically - One variable at a time
5. Log findings - Document each test and result
6. Identify root cause - Narrow down definitively
7. Propose fix - With before/after code
8. Verify - Confirm fix works, no regression
9. Prevent recurrence - Suggest test to add