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.
View on GitHubJanuary 21, 2026
Select agents to install to:
npx add-skill https://github.com/JNLei/claude-tools/blob/main/plugins/skills/skill-developer/skills/skill-developer/SKILL.md -a claude-code --skill skill-developerInstallation paths:
.claude/skills/skill-developer/# 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 ### Two-Hook Architecture **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 - **Method**: Injects formatted reminder as context (stdout → Claude's input) - **Use Cases**: Topic-based skills, implicit work detection **2. Stop Hook - Error Handling Reminder** (Gentle Reminders) - **File**: `.claude/hooks/error-handling-reminder.ts` - **Trigger**: AFTER Claude finishes responding - **Purpose**: Gentle reminder to self-assess error handling in code written - **Method**: Analyzes edited files for risky patterns, displays reminder if needed - **Use Cases**: Error handling awareness without blocking friction **Philosophy Change (2025-10-27):** We moved away from blocking PreToolUse for Sentry/error handling. Instead, use gentle post-response reminders that don't block workflow but maintain code quality awareness. ### Configuration File **Location**: `.claude/skills/skill-rules.json` Defines: - All skills and their trigger conditions - Enforcement levels (block, suggest, warn) - File path patterns (glob) - Content detection patterns (regex) - Skip conditions (session tracking, file markers, env vars) --- ## Skill Types ### 1. Guardrail Skills **Purpose:** Enforce critica