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Root Cause Tracing

Systematically trace bugs backward through call stack to find original trigger. Use when errors occur deep in execution and you need to trace back to find the original trigger.

By secondsky
20230Updated 1 week agoTypeScriptMIT

Skill Content

# 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.

## When to Use

**Use 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

## The Tracing Process

### 1. Observe the Symptom
```
Error: git init failed in ~/project/packages/core
```

### 2. Find Immediate Cause
**What code directly causes this?**
```typescript
await execFileAsync('git', ['init'], { cwd: projectDir });
```

### 3. Ask: What Called This?
```typescript
WorktreeManager.createSessionWorktree(projectDir, sessionId)
  ā†’ called by Session.initializeWorkspace()
  ā†’ called by Session.create()
  ā†’ called by test at Project.create()
```

### 4. Keep Tracing Up
**What value was passed?**
- `projectDir = ''` (empty string!)
- Empty string as `cwd` resolves to `process.cwd()`
- That's the source code directory!

### 5. Find Original Trigger
**Where did empty string come from?**
```typescript
const context = setupCoreTest(); // Returns { tempDir: '' }
Project.create('name', context.tempDir); // Accessed before beforeEach!
```

## Adding Stack Traces

When you can't trace manually, add instrumentation:

```typescript
// Before the problematic operation
async function gitInit(directory: string) {
  const stack = new Error().stack;
  console.error('DEBUG git init:', {
    directory,
    cwd: process.cwd(),
    nodeEnv: process.env.NODE_ENV,
    stack,
  });

  await execFileAsync('git', ['init'], { cwd: directory });
}
```

**Critical:** Use `console.error()` in tests (not logger - may not show)

**Run and capture:**
```bash
bun test 2>&1 | grep 'DEBUG git init'
```

**Analyze stack traces:**
- Look for test file names
- Find the line number triggering the call
- Identify the pattern (same test? same parameter?)

## Finding Which Test Causes Pollution

If something appears during tests but you don't know which test:

Use the bisection script to run tests one-by-one:

```bash
# Example: find which test creates .git in wrong place
bun test --run --bail 2>&1 | tee test-output.log
```

Runs tests one-by-one, stops at first polluter.

## Real Example: Empty projectDir

**Symptom:** `.git` created in `packages/core/` (source code)

**Trace chain:**
1. `git init` runs in `process.cwd()` ā† empty cwd parameter
2. WorktreeManager called with empty projectDir
3. Session.create() passed empty string
4. Test accessed `context.tempDir` before beforeEach
5. setupCoreTest() returns `{ tempDir: '' }` initially

**Root cause:** Top-level variable initialization accessing empty value

**Fix:** Made tempDir a getter that throws if accessed before beforeEach

**Also added defense-in-depth:**
- Layer 1: Project.create() validates directory
- Layer 2: WorkspaceManager validates not empty
- Layer 3: NODE_ENV guard refuses git init outside tmpdir
- Layer 4: Stack trace logging before git init

## Key Principle

**NEVER fix just where the error appears.** Trace back to find the original trigger.

## Stack Trace Tips

**In tests:** Use `console.error()` not logger - logger may be suppressed
**Before operation:** Log before the dangerous operation, not after it fails
**Include context:** Directory, cwd, environment variables, timestamps
**Capture stack:** `new Error().stack` shows complete call chain

## Real-World Impact

From debugging session:
- Found root cause through 5-level trace
- Fixed at source (getter validation)
- Added 4 layers of defense
- 1847 tests passed, zero pollution

How to use

  1. Copy the skill content above
  2. Create a .claude/skills directory in your project
  3. Save as .claude/skills/claude-skills-root-cause-tracing.md
  4. Use /claude-skills-root-cause-tracing in Claude Code to invoke this skill

README

View on GitHub

Claude Code Skills Collection

142 production-ready skills for Claude Code CLI

Version 3.5.0 | Last Updated: 2026-07-18

<div align="center">

šŸ”Œ Platform Support

This repository uses Claude Plugin Patterns ā€” natively supported by:

PlatformStatusNotes
Claude Codeāœ… NativeFull marketplace support
Factory Droidāœ… NativeFull marketplace support
</div> **For all other Platforms like opencode, codex and others, you can use https://github.com/enulus/OpenPackage **

A curated collection of battle-tested skills for building modern web applications with Cloudflare, AI integrations, React, Tailwind, and more.

PS: if skills.sh warns about any skill: Their scan process is a outdated LLM which flags newest versions pins (like in ZOD) as non existent and by that potentially malicous.

Quick Start

Marketplace Installation (Recommended)

# Add the marketplace
/plugin marketplace add https://github.com/secondsky/claude-skills

# Install individual skills as needed
/plugin install cloudflare-d1@claude-skills
/plugin install tailwind-v4-shadcn@claude-skills
/plugin install gemini-cli@claude-skills

See MARKETPLACE.md for complete catalog of all 139 skills.

Bulk Installation (Contributors)

# Clone the repository
git clone https://github.com/secondsky/claude-skills.git
cd claude-skills

# Install all 139 skills at once
./scripts/install-all.sh

# Or install individual skills
./scripts/install-skill.sh cloudflare-d1

Repository Structure

This repository contains 139 production-tested skills for Claude Code, each focused on a specific technology or capability.

Individual Skills: Each skill is a standalone unit with:

  • SKILL.md - Core knowledge and guidance
  • Templates - Working code examples
  • References - Extended documentation
  • Scripts - Helper utilities

Installation Options:

  1. Individual - Install only the skills you need via marketplace
  2. Bulk - Install all 139 skills using ./scripts/install-all.sh

Available Skills (139 Individual Skills)

Each skill is individually installable. Install only the skills you need.

Full Catalog: See MARKETPLACE.md for detailed listings.

Categories

CategorySkillsExamples
tooling22turborepo, plan-interview, code-review
frontend26nuxt-v4, nuxt-v5, tailwind-v4-shadcn, tanstack-query, nuxt-studio, maz-ui, threejs
cloudflare21cloudflare-d1, cloudflare-workers-ai, cloudflare-agents
api16api-design-principles, graphql-implementation
ai7gemini-cli, ml-model-training, tanstack-ai
web10hono-routing, firecrawl-scraper, web-performance
security5csrf-protection, xss-prevention
mobile5react-native-app, react-native-skills
woocommerce4woocommerce-backend-dev
testing4vitest-testing, playwright-testing
design4design-review, design-system-creation
auth4better-auth
architecture3microservices-patterns, architecture-patterns
data2recommendation-engine, recommendation-system
cms2hugo, wordpress-plugin-core
database1drizzle-orm-d1
seo2seo-optimizer, seo-keyword-cluster-builder
documentation1technical-specification

How It Works

Auto-Discovery

Claude Code automatically checks ~/.claude/skills/ for relevant skills before planning tasks:

User: "Set up a Cloudflare Worker with D1 database"
           ā†“
Claude: [Checks skills automatically]
           ā†“
Claude: "Found cloudflare-d1 skills.
         These prevent 12 documented errors. Use them?"
           ā†“
User: "Yes"
           ā†“
Result: Production-ready setup, zero errors, ~65% token savings

Note: Due to token limits, not all skills may be visible at once. See āš ļø Important: Token Limits below.

Skill Structure

Each skill includes:

skills/[skill-name]/
ā”œā”€ā”€ SKILL.md              # Complete documentation
ā”œā”€ā”€ .claude-plugin/
ā”‚   ā””ā”€ā”€ plugin.json       # Plugin metadata
ā”œā”€ā”€ templates/            # Ready-to-copy templates
ā”œā”€ā”€ scripts/              # Automation scripts
ā””ā”€ā”€ references/           # Extended documentation

Recent Additions

July 2026

Offensive Security (new category):

  • cybersecurity ā€” Unified OSS-only cybersecurity skill with progressive disclosure. Fuses 7 community skills (mukul975 business-logic/XSS/host-header/forced-browsing/open-redirect, rysweet/amplihack cybersecurity-analyst, Aradotso security-detections-mcp) ported to fully open-source tooling (OWASP ZAP, Dalfox, ffuf, Nuclei, mitmproxy, interact.sh, Semgrep, Sigma). Covers threat modeling (STRIDE/PASTA/VAST, MITRE ATT&CK), web-vuln testing, SAST, code audit, AI/LLM-app security, and detection engineering. Live-target testing is gated behind an authorization disclaimer; static analysis, code review, and threat modeling are always available. Cross-references the 5 existing defensive security plugins (csrf-protection, xss-prevention, vulnerability-scanning, security-headers-configuration, defense-in-depth-validation) for remediation. Integrates 20 Aradotso dev-security skills across 5 grouped reference docs.

May 2026

Supply Chain Security (cross-cutting):

  • dependency-upgrade expanded with Socket CLI integration ā€” proactive malicious package detection, typosquatting alerts, and CI/CD security gates. New 418-line reference guide, 2 GitHub Actions templates, and expanded supply chain security comparison (3 tools)
  • 31 skills now include "Secure Installation" guidance ā€” contextually-tailored security sections across all high-risk skill categories (scaffolding, MCP/agent SDKs, multi-provider installs, Docker, CI/CD). Covers 8 Bun skills, 5 Nuxt skills, 6 Cloudflare skills, 4 AI/agent skills, and 8 frontend/tooling skills
  • Supply chain security is now a first-class cross-cutting concern woven into the skill collection ā€” not a standalone topic

February - April 2026

Full-Stack Frameworks:

  • nuxt-v5 (v1.0.0) - Full Nuxt 5 support with 4 skills (core, data, server, production), 3 diagnostic agents, and interactive setup wizard
  • threejs (v1.0.0) - 3D web graphics: scenes, geometries, shaders, animations, post-processing

Infrastructure:

  • JSON schema validation - Automated plugin.json validation with CI support
  • GitHub issue templates - Skill-specific issue templates for bug reports, feature requests, and submissions

Plugin Enhancements:

  • mutation-testing - Added Bun native runner support
  • dependency-upgrade - Added supply chain security content

December 2025 - January 2026

Frontend Expansion:

  • nuxt-studio (v1.0.0) - Visual CMS for Nuxt Content with live preview, OAuth auth, and R2 storage integration
  • maz-ui (v1.0.0) - 50+ Vue/Nuxt components with theming, i18n, form generation, and 14 composables

Developer Workflow:

  • plan-interview (v2.0.0) - Adaptive interview-driven spec generation with autonomous quality review
  • turborepo (v2.8.0) - Updated to official Vercel skill with enhanced monorepo build optimization

Mobile Development:

  • react-native-skills (v1.0.0) - React Native & Expo best practices with performance optimization patterns

Enhanced Authentication:

  • better-auth (v2.2.0) - Expanded to 18 framework integrations with 30+ authentication plugins

āš ļø Important: Token Limits

Skill Visibility Constraint

Claude Code has a 15,000 character limit for the total size of skill descriptions in the system prompt. This limit also applies to commands and agents.

What this means:

  • Not all 139 skills may be visible in Claude's context at once
  • Skills are loaded based on relevance and available token budget
  • You can verify how many skills Claude currently sees by asking: "How many skills do you see in your system prompt?"

Checking Visible Skills

To verify which skills are currently loaded:

# Ask Claude Code directly
"Check what skills/plugins you see in your system prompt"

Claude will report something like: "85 of 139 skills visible due to token limits"

Workaround: Increase Token Budget

You can double the headroom for skill descriptions by setting an environment variable:

# Increase limit to 30,000 characters
export SLASH_COMMAND_TOOL_CHAR_BUDGET=30000

# Then launch Claude Code
claude

This gives you approximately 2x more skill visibility in the system prompt.

Note: This is a temporary workaround. The Claude Code team is working on better solutions for skill discovery and loading.

Token Efficiency

MetricManual SetupWith SkillsSavings
Average Tokens12,000-15,0004,000-5,000~65%
Typical Errors2-4 per service0 (prevented)100%
Setup Time2-4 hours15-45 minutes~80%

Across all 139 skills: 400+ documented errors prevented.

Contributing

Prerequisites for Contributors

Install the official plugin development toolkit:

/plugin install plugin-dev@claude-code-marketplace

This provides:

  • /plugin-dev:create-plugin command (8-phase guided workflow)
  • 7 comprehensive skills (hooks, MCP, structure, agents, commands, skills)
  • 2 specialized agents (agent-creator, plugin-validator)

Quick Steps

  1. Create skill directory in plugins/
  2. Add SKILL.md with YAML frontmatter
  3. Run ./scripts/sync-plugins.sh
  4. Submit pull request

See CONTRIBUTING.md and PLUGIN_DEV_BEST_PRACTICES.md for detailed guidelines.

Documentation

DocumentPurpose
START_HERE.mdStart here! Quick navigation guide
PLUGIN_DEV_BEST_PRACTICES.mdRepository-specific best practices (marketplace, budget, quality)
MARKETPLACE.mdFull skill catalog and installation guide
MARKETPLACE_MANAGEMENT.mdTechnical infrastructure (plugin.json, scripts, validation)
CLAUDE.mdProject context and development standards
CONTRIBUTING.mdContribution guidelines

Links

Built with ā¤ļø by Claude Skills Maintainers

View source on GitHub