# AI Debug

> Finds the root cause of broken behaviour and names it at file:line, then writes the check that fails for that reason before changing anything. Also resolves merge and rebase conflicts by intent rather than by taking a side. Trigger for "it's not working", "this used to work", "I'm getting an error", "CI is failing", "why is X happening", "I have conflicts", "the rebase failed". Not for adding test coverage to working code — use /ai-review. Not for exploring an unfamiliar area — use /ai-explore. Not for designing the fix — once the cause is named, use /ai-plan.

- Skill: `arcasilesgroup/ai-debug` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add arcasilesgroup/ai-debug`
- Raw SKILL.md: https://api.skillmd.com/api/skills/arcasilesgroup/ai-debug/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools, Security
- License: Apache-2.0
- Author: arcasilesgroup (https://skillmd.com/u/arcasilesgroup)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/arcasilesgroup/ai-debug

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# Find the cause, not the symptom

## What it produces

A named cause at `file:line`, a check that fails because of it, and only then a fix.

## Steps

1. Reproduce it. If you cannot reproduce it, say so plainly and stop guessing: the next
   useful thing is a way to reproduce it, not a change.
2. Read the failing output in full. The first error is usually the real one and the rest
   are its consequences; the last error is the one people paste.
3. Name a cause you can point at. `file:line`, and one sentence on why that line produces
   this symptom. "Probably a race" is not a cause. If two causes are plausible, say which
   observation would tell them apart, then go and make that observation.
4. Before the fix, write the check that fails for this reason. A fix with no failing check
   before it is a change with an opinion attached.
5. Fix the cause, at the place all the callers go through. Patching the one path the report
   named leaves every sibling caller broken, and the shared fix is usually the smaller diff.
6. Run the check. Then run the suite. Then say what you changed and why it fixes the cause
   you named, not the symptom that was reported.
7. If you are two attempts in and it is still not fixed, stop and say so. That is a rule,
   not a suggestion: the third attempt is where the guessing starts.

## Conflicts

Read both sides for intent before touching either. Lock files and generated files are
regenerated, never merged by hand. Migrations are ordered, not combined. If two people
meant different things, that is a conversation, not a resolution.

## What this is not

- "I know what the bug is even though I cannot reproduce it" — a cause you cannot reproduce is a guess: the next useful thing is a way to reproduce it, not a change.

## Done when

- The cause is named at `file:line` and a person could disagree with it.
- A check exists that fails without the fix and passes with it.
- You said what you changed, in a sentence somebody could act on.