# Skill Developer

Create and manage Claude Code skills following Anthropic best practices.

- Repository: https://github.com/diet103/claude-code-infrastructure-showcase (10043 stars)
- Category: Testing
- License: MIT
- Last updated: 2026-07-13
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add diet103/claude-code-infrastructure-showcase --skill skill-developer -g -a claude-code -y`
Codex: `npx skills add diet103/claude-code-infrastructure-showcase --skill skill-developer -g -a codex -y`
Cursor: `npx skills add diet103/claude-code-infrastructure-showcase --skill skill-developer -g -a cursor -y`
Gemini CLI: `npx skills add diet103/claude-code-infrastructure-showcase --skill skill-developer -g -a gemini-cli -y`

## Description

Create and manage Claude Code skills following Anthropic best practices. Use when creating new skills, modifying skill-rules.json, understanding trigger patterns, working with hooks, debugging skill activation, or implementing progressive disclosure. Covers skill structure, YAML frontmatter, trigger types (keywords, intent patterns, file paths, content patterns), enforcement levels (block, suggest, warn), hook mechanisms (UserPromptSubmit, PreToolUse), session tracking, and the 500-line rule.

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

# Skill Developer Guide

## Purpose

Comprehensive guide for creating and managing skills in Claude Code with auto-activation system, following Anthropic's official best practices including the 500-line rule and progressive disclosure pattern.

## When to Use This Skill

Automatically activates when you mention:
- Creating or adding skills
- Modifying skill triggers or rules
- Understanding how skill activation works
- Debugging skill activation issues
- Working with skill-rules.json
- Hook system mechanics
- Claude Code best practices
- Progressive disclosure
- YAML frontmatter
- 500-line rule

---

## System Overview

### Hook Architecture (five wired hooks)

**1. UserPromptSubmit Hook** (Proactive Suggestions)
- **File**: `.claude/hooks/skill-activation-prompt.ts`
- **Trigger**: BEFORE Claude sees user's prompt
- **Purpose**: Suggest relevant skills based on keywords + intent patterns (regex or optional AI classification)
- **Method**: Injects formatted reminder as context (stdout → Claude's input)
- **Enforcement**: Only `enforcement: "block"` skills are marked MANDATORY; `suggest`/`warn` skills always appear as recommendations

**2. PreToolUse Hook - Skill Verification Guard** (Enforcement)
- **File**: `.claude/hooks/skill-verification-guard.ts`
- **Trigger**: BEFORE Edit/MultiEdit/Write executes
- **Purpose**: Enforce mandatory skill activation (two-try model) and guardrail file/content patterns; optional AI edit analysis
- **Method**: Exit code 2 + stderr blocks the tool; only `enforcement: "block"` skills can block

**3. PostToolUse Hook - Edit Tracker**
- **File**: `.claude/hooks/post-tool-use-tracker.sh`
- **Trigger**: AFTER Edit/MultiEdit/Write completes
- **Purpose**: Track edited files and repos (feeds build checks and the error-handling reminder)

The rest: https://github.com/diet103/claude-code-infrastructure-showcase/blob/HEAD/.agents/skills/skill-developer/SKILL.md