What is the 500-line rule for Claude Code skills?

The 500-line rule is an Anthropic best practice recommending that main SKILL.md files remain under 500 lines to maintain focus and context window efficiency, utilizing reference files for more granular details.

What is the purpose of the UserPromptSubmit hook?

The UserPromptSubmit hook allows the system to proactively suggest relevant skills to Claude before it processes a user's prompt, injecting context based on detected intent.

How can I debug a skill that isn't activating?

You can debug activation by setting the SKILL_DEBUG=true environment variable or using the 'yarn lint:skill' and 'dev:skill' commands to view the underlying matching logic.

How do triggers work in Claude Code skills?

Skills are activated via keyword matching (exact substrings) or intent patterns (regex matching) defined in the skill-rules.json configuration file.

Writing Claude Code Skills

Name: Writing Claude Code Skills
Author: Activer007

byActiver007

0•

Learning & Documentation

Provides comprehensive guidance for creating, managing, and debugging custom skills in Claude Code following Anthropic's official best practices.

This skill serves as a meta-framework for developers looking to extend Claude Code's capabilities. It provides the architectural patterns needed to build efficient, auto-activating skills, covering everything from YAML frontmatter and the 500-line rule to complex regex intent patterns and hook system mechanics. By implementing progressive disclosure and standardized validation techniques, it ensures that custom AI enhancements remain maintainable, performant, and perfectly aligned with Claude's operational constraints.

Key Features

01Standardized YAML frontmatter and metadata structure

02UserPromptSubmit hook implementation mechanics

03Automated skill activation debugging tools

04Anthropic 500-line rule enforcement guide

05Custom trigger and intent pattern templates

060 GitHub stars

Use Cases

01Building domain-specific knowledge bases for specialized engineering teams

02Standardizing AI behavior and documentation patterns across a codebase

03Debugging and refining complex skill activation triggers in Claude Code

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add activer007/ordinary-claude-skills writing-skills

For use in Claude.ai and ChatGPT

Download Skill