# Troubleshooting Rca

> Perform root-cause analysis for bugs/errors/regressions using logs, repro steps, and hypothesis testing. Use when the user reports “nie działa”, stack traces, failing tests, or regressions.

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

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# troubleshooting-rca

## Activation gate (anti-noise)
Activate when:
- There is an error message, failing test, crash, regression, unexpected behavior, or logs.

Skip when:
- User requests implementation from scratch and no failure exists yet.

## Procedure
1. Restate symptom + expected behavior.
2. Collect minimal repro:
   - Command, input, environment, last known good commit.
3. Hypotheses (max 3) ranked by likelihood.
4. Test each hypothesis with the smallest possible check.
5. **Before Fix:** Root cause must be clearly stated; one minimal verification step must be given. Then: Fix + verify with test/run.
6. Add a prevention note (test, guard, logging).

## Output
- Symptom → Most likely cause → Fix → Verification command(s).