# Root Cause Analysis

Performs systematic root cause analysis to identify the true source of bugs, errors...

- Repository: https://github.com/rohitg00/skillkit (1568 stars)
- Category: Testing
- License: Apache-2.0
- Last updated: 2026-06-02
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add rohitg00/skillkit --skill root-cause-analysis -g -a claude-code -y`
Codex: `npx skills add rohitg00/skillkit --skill root-cause-analysis -g -a codex -y`
Cursor: `npx skills add rohitg00/skillkit --skill root-cause-analysis -g -a cursor -y`
Gemini CLI: `npx skills add rohitg00/skillkit --skill root-cause-analysis -g -a gemini-cli -y`

## Description

Performs systematic root cause analysis to identify the true source of bugs, errors, and unexpected behavior through structured investigation phases, not just treating symptoms. Use when a user reports a bug, crash, error, or broken behavior and needs to debug, troubleshoot, or investigate why something is not working; especially for complex or intermittent issues across multiple components. Applies the Five Whys method, hypothesis-driven testing, stack trace analysis, git blame/log evidence gathering, and causal chain documentation to isolate and confirm root causes before applying any fix.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Root Cause Analysis

You are performing systematic root cause analysis to find the true source of a bug. Do not apply fixes until you understand WHY the bug exists.

## Core Principle

**Never fix a symptom. Always find and fix the root cause.**

## The Five Whys Method

Ask "Why?" repeatedly to drill down to the root cause:

1. **Why** did the API return an error? → The database query failed
2. **Why** did the database query fail? → The connection pool was exhausted
3. **Why** was the pool exhausted? → **ROOT CAUSE:** Missing `finally` block to close connections

## Investigation Phases

### Phase 1: Reproduce the Bug

Before investigating:

1. **Reproduce consistently** - If you can't reproduce it, you can't verify a fix
2. **Document reproduction steps** - Exact sequence of actions
3. **Note environment details** - OS, versions, configuration
4. **Identify minimal reproduction** - Smallest case that shows the bug

Questions to answer:
- Does it happen every time or intermittently?
- Does it happen in all environments?
- When did it start happening? (recent changes)

### Phase 2: Gather Evidence

Collect information before forming theories:

- Error messages and stack traces
- Log files (application, system, database)
- Recent code changes (git log, blame)
- User reports and reproduction steps
- Monitoring data (metrics, APM)
- Related issues (search issue tracker)

Do NOT:
- Make changes while gathering evidence
- Assume you know the cause without evidence
- Ignore related symptoms

### Phase 3: Form Hypotheses

Based on evidence, create ranked hypotheses:

| Priority | Hypothesis | Evidence | Test Plan |
|----------|------------|----------|-----------|
| 1 | Connection leak in UserService | Stack trace shows connection pool | Add logging, check usage |
| 2 | Query timeout too short | Occurs under load | Test with longer timeout |
| 3 | Database server overload | Correlates with peak hours | Check DB metrics |

The rest: https://github.com/rohitg00/skillkit/blob/HEAD/packages/core/src/methodology/packs/debugging/root-cause-analysis/SKILL.md