# Debugging Patterns

> Root cause analysis frameworks including log-first investigation, git bisect correlation, and pattern-based diagnosis with confidence scoring.

- Skill: `majiayu000/debugging-patterns-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/debugging-patterns-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/debugging-patterns-2/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/debugging-patterns-2

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# Debugging Patterns

## Overview

Provides structured frameworks for root cause analysis. The log-first methodology ensures evidence is gathered before hypotheses are formed.

## Log-First Investigation

1. Read ALL available logs, error output, and stack traces
2. DO NOT form hypotheses before reading evidence
3. Identify the exact error: message, file, line, call stack
4. Determine reproduction steps from evidence
5. Check git log for recent changes correlating with bug introduction

## Pattern-Based Diagnosis

- Check patterns.md for known gotchas matching the error
- Cross-reference with common patterns: null pointer, race condition, resource leak, config error
- Rate root cause confidence (>=80% to proceed with fix)

## Evidence Collection

- Stack traces with full call chain
- Error messages with context
- Exit codes from reproduction attempts
- Git blame/log for change correlation
- Environment differences (if applicable)

## When to Use

- During DEBUG workflow investigation phase
- When BUILD tests fail unexpectedly
- When reviewing error handling gaps

## Agents Used

- `bug-investigator` (primary consumer)
- `silent-failure-hunter` (pattern reference)