# root-cause-tracing

This skill follows a failure up the call chain to its original trigger. Use it when a stack trace is long or the source of a value is unclear.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 373 installs · ★ 78
- Author: bobmatnyc
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/bobmatnyc/claude-mpm-skills/tree/HEAD/universal/debugging/root-cause-tracing/SKILL.md
- Updated: 2026-07-18
- HTML: https://affpapa.org/en/nevibecode/skills/bobmatnyc-root-cause-tracing

## What it does

The skill starts at the point where an error appears and moves upward through the call chain. It identifies the symptom, finds the immediate cause, checks which code called it, and keeps tracing until it reaches the original trigger. The fix is then made at the source, with checks added across later layers.

It targets failures deep in execution, long stack traces, and data whose origin is unclear. The skill includes a step-by-step tracing process, a decision tree, tracing methods, examples, and guidance for adding instrumentation. When the caller cannot be identified, it recommends logging context before the risky operation.

The practical boundary is clear: root-cause-tracing is used inside systematic-debugging during Phase 1. It does not replace that workflow. Its settings include `context_limit: 800`; user invocation is disabled, as is automatic model invocation.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill root-cause-tracing -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/root-cause-tracing/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/root-cause-tracing/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill root-cause-tracing -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/root-cause-tracing/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill root-cause-tracing -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/root-cause-tracing/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install bobmatnyc/claude-mpm-skills root-cause-tracing
```

2. **Manually: put the files in place**
- File: `.github/skills/root-cause-tracing/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill root-cause-tracing -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/bobmatnyc/claude-mpm-skills --path universal/debugging/root-cause-tracing
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/root-cause-tracing/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add bobmatnyc/claude-mpm-skills --skill root-cause-tracing -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/bobmatnyc/claude-mpm-skills/tree/HEAD/universal/debugging/root-cause-tracing/SKILL.md

## When to use it
- trace a failure to its original trigger
- find where an invalid value or path entered the call chain
- separate the visible symptom from the underlying cause
- add validation after fixing the source

## Example prompts
- Apply root-cause-tracing to this failure and follow the call chain back to the original trigger.
- Find where the empty working-directory path comes from, then fix the source.
- Trace the invalid state to its origin and add checks at the later layers.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 2788f1eb88cf0ab1.

BEGIN THIRD-PARTY FILE 2788f1eb88cf0ab1
````text
---
name: root-cause-tracing
description: Systematically trace bugs backward through call stack to find original trigger
user-invocable: false
disable-model-invocation: true
when_to_use: when errors occur deep in execution and you need to trace back to find the original trigger
version: 2.0.0
languages: all
progressive_disclosure:
  entry_point:
    summary: "Trace bugs backward through call chains to find original triggers instead of fixing symptoms"
    when_to_use: "When errors manifest deep in execution, unclear data origins, or long call chains. Use AFTER systematic-debugging Phase 1."
    quick_start: "1. Observe symptom 2. Find immediate cause 3. Ask what called this 4. Keep tracing up 5. Fix at source + add defense"
  references:
    - tracing-techniques.md
    - examples.md
    - advanced-techniques.md
    - integration.md
context_limit: 800
tags:
  - debugging
  - root-cause
  - tracing
  - call-stack
---

# Root Cause Tracing

## Overview

Bugs often manifest deep in the call stack (git init in wrong directory, file created in wrong location, database opened with wrong path). Your instinct is to fix where the error appears, but that's treating a symptom.

**Core principle:** Trace backward through the call chain until you find the original trigger, then fix at the source.

This skill is a specialized technique within the systematic-debugging workflow, typically applied during Phase 1 (Root Cause Investigation) when dealing with deep call stacks.

## When to Use This Skill

**Use root-cause-tracing when:**
- Error happens deep in execution (not at entry point)
- Stack trace shows long call chain
- Unclear where invalid data originated
- Need to find which test/code triggers the problem
- Symptom appears far from actual cause

**Relationship with systematic-debugging:**
- systematic-debugging: The overall framework (Phases 1-4)
- root-cause-tracing: A specific technique for Phase 1 investigation
- Use root-cause-tracing WITHIN systematic-debugging Phase 1

## The Iron Law

```
NEVER FIX JUST WHERE THE ERROR APPEARS
ALWAYS TRACE BACK TO FIND THE ORIGINAL TRIGGER
```

Fixing symptoms creates bandaid solutions that mask root problems.

## Core Principles

1. **Trace Backward**: Follow call chain from symptom to source
2. **Find Original Trigger**: Identify where bad data/state originated
3. **Fix at Source**: Address root cause, not symptom
4. **Defense-in-Depth**: Add validation at each layer after fixing source

## Quick Start

### The 5-Step Trace Process

1. **Observe the Symptom**: What error message? What failed operation?
2. **Find Immediate Cause**: What code directly causes this error?
3. **Ask What Called This**: Trace one level up the call stack
````
END THIRD-PARTY FILE 2788f1eb88cf0ab1

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