Skill Claude CodeCodex
Enforce markdown formatting and structure conventions when writing or editing .md files. Use when creating markdown documents, editing AGENTS.md files, writing documentation, or reviewing markdown for consistency.
Skill Claude CodeCodex
Enforce shell script style conventions when writing or editing .sh files. Use when creating shell scripts, modifying existing scripts, or reviewing shell code for style and portability.
Skill Claude CodeCodex
Create or update portable agent skills in .agents/skills/. Use when asked to create a skill, improve an existing skill, build a slash command, or set up a reusable workflow. Guides through skill design, writes SKILL.md with proper frontmatter, and creates supporting files.
Hook Claude Code
Runs when a session starts on startup, executing claude.sh. From nevir/agentfill.
Settings file Claude Code
Agent settings declaring 1 hook event (SessionStart) and 3 allowed tools.
Instructions file CodexOpenCode
AGENTS.md instructions for nevir/agentfill, covering agentfill project, documentation, test suite context, pre-commit checklist and after modifying src/ files.
Agent
Aider is a terminal-based AI pair programming tool. It does not have a skills system comparable to the Agent Skills specification, but uses a conventions system (read:) for loading context files and coding standards.
Agent
Claude Code is Anthropic's official CLI for Claude. It features a comprehensive hooks system, native Agent Skills support, and a plugin mechanism for extensibility.
Agent
OpenAI Codex CLI is OpenAI's command-line coding agent. It features full native support for the Agent Skills specification, a built-in skill installer, and environment variable configuration for custom skill directories.
Agent
GitHub Copilot CLI is GitHub's command-line coding agent. It features full Agent Skills support (announced December 2025), custom agents, and automatic loading of cross-agent context files including AGENTS.md and .claude/skills/.
Agent
Cursor provides both an IDE and a standalone CLI agent. These are independent products with different capabilities.
Agent
Gemini CLI is Google's command-line interface for Gemini. It features a comprehensive hooks system, native Agent Skills support (experimental), and a robust extension system for extensibility.
Agent
When creating tests for AGENTS.md support, follow these principles to ensure tests are reliable, portable, and maintainable.
Skill Claude CodeCodex
Use this skill when asked about the global skill code.
Skill Claude CodeCodex
Use this skill when asked about the magic skill code or secret skill phrase.