systematic-debugging

# Systematic Debugging

## Collab Session Required

Before proceeding, check for active collab session:

1. Check if `.collab/` directory exists
2. Check if any session folders exist within
3. If no session found:
   ```
   ⚠️ No active collab session found.

   Use /collab to start a session first.
   ```
   **STOP** - do not proceed with this skill.

4. If multiple sessions exist, check `COLLAB_SESSION_PATH` env var or ask user which session.

## Get Current Work Item

After confirming collab session:

1. Read `collab-state.json` from the session folder
2. Get `currentItem` number from state
3. Read design doc and find the item with that number
4. Display: "Investigating: {item.title}"

This item context determines what bug is being investigated.

## EXPLICIT PROHIBITION

```
⚠️ DO NOT IMPLEMENT FIXES

- No editing source files to fix the bug
- No writing fix code
- Document only
- Fixes happen later via rough-draft → executing-plans
```

The following are FORBIDDEN in this skill:
- Using Edit tool on source files (except design doc)
- Using Write tool on source files
- Making any code changes to fix the bug
- Implementing the fix

## Overview

Random fixes waste time and create new bugs. Quick patches mask underlying issues.

**Core principle:** ALWAYS find root cause before attempting fixes. Symptom fixes are failure.

**Violating the letter of this process is violating the spirit of debugging.**

## The Iron Law

```
NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST
```

If you haven't completed Phase 1, you cannot propose fixes.

## When to Use

Use for ANY technical issue:
- Test failures
- Bugs in production
- Unexpected behavior
- Performance problems
- Build failures
- Integration issues

**Use this ESPECIALLY when:**
- Under time pressure (emergencies make guessing tempting)
- "Just one quick fix" seems obvious
- You've already tried multiple fixes
- Previous fix didn't work
- You don't fully understand the issue

**Don't skip when:**
- Issue seems simple (