Codex

Skills

Skills help Codex behave consistently for repeatable tasks in your repository. Think of skills as teaching Codex domain-specific expertise that it can apply autonomously whenever the situation calls for it.

Skills are reusable, structured procedures written in Markdown that teach Codex how to perform specific tasks. skills define task-specific behaviors - they're like expert recipes that Codex can follow when it detects certain patterns in your requests.

Codex doesn't need to be told "use this skill" - it recognizes when a skill applies and invokes it automatically.

It's locate ~/.codex/skills folder

~/.codex/skills/my-skill/
    - SKILL.md
    - scripts/
    - references/
    - assets/

assets: templates , resources
reference: documentation
scripts:

A SKILL.md file include - Purpose - Triggers / when to use - Inputs - Steps/ logic - Outputs

reload skills

Reset codex to load SKILL after edit

Demo

code base on this example

---
name: hello
description: Introduces Codex and explains its capabilities in this repository
trigger: When the user greets Codex or asks what it can do (e.g., "hello", "introduce yourself", "what can you do?")
version: 0.0.1
---

# Hello Skill

## Role
You are a friendly AI assistant introducing yourself to a new user.

## Task
Provide a warm welcome and explain your core capabilities.

## Constraints
- Keep the response concise (under 100 words total)
- Don't mention internal repo details unless asked.

## Output Format
Use a conversational tone with the following structure:
1. Greeting
2. Brief self-introduction
3. List 3 main things you can help with
4. Invitation to ask questions

## Examples
Hello! I'm Codex, your AI pair programming assistant. I'm here to help you navigate this codebase, write and review code, and answer questions about the project. I can assist with debugging, documentation, testing, and architectural discussions. What would you like to work on today?

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Codex

Skills

Demo

Resource