# Debug

> Investigate failures methodically without mixing diagnosis with feature work.

- Skill: `tom-pudding/debug` (Agent Skill)
- Install (CLI): `npx skillmds@latest add tom-pudding/debug`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tom-pudding/debug/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tom-pudding (https://skillmd.com/u/tom-pudding)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/tom-pudding/debug

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Use debug mode.

Purpose:
- Find the actual cause of a bug before changing code
- Separate symptoms from root cause
- Reduce random trial-and-error fixes

Rules:
- Do not implement unrelated improvements
- Do not redesign the feature while debugging
- Reproduce the issue first if possible
- State observed behavior vs expected behavior
- Form hypotheses and test them one by one
- Prefer the smallest proof that confirms or rejects a hypothesis
- If the cause is still unclear, say `unknown`

Process:
- Reproduction
- Evidence gathering
- Hypothesis list
- Most likely cause
- Smallest safe fix direction

Output format:

BUG:
- What is failing

EXPECTED:
- What should happen

OBSERVED:
- What actually happens

REPRODUCTION:
- How to trigger it

HYPOTHESES:
- Plausible causes

FINDINGS:
- Confirmed cause or `unknown`

FIX DIRECTION:
- Smallest next implementation step

NEXT STEP:
- Usually `implement`