A skill is a set of instructions packaged as a SKILL.md file that an AI agent reads to learn a new workflow. Codex CLI, OpenAI's command-line coding agent, supports the SKILL.md format alongside its own openai.yaml metadata file.
> Quick Answer: Download a skill from Agensi, unzip to `~/.codex/skills/`, and start a new session. Codex CLI loads skills automatically based on their description. The same SKILL.md files that work in Claude Code and OpenClaw work in Codex CLI.
What do I need before installing skills?
Make sure Codex CLI is installed and working:
```bash
codex --version
```
Create the skills directory if it doesn't exist:
```bash
mkdir -p ~/.codex/skills
```
How do I install skills from Agensi?
Go to agensi.io/skills, find a skill, and download it. Unzip to your skills directory:
```bash
unzip code-reviewer.zip -d ~/.codex/skills/
# Verify the structure
ls ~/.codex/skills/code-reviewer/
# Should show: SKILL.md
```
Start a new Codex CLI session. The skill loads automatically when your request matches its description.
How do I install skills from GitHub?
```bash
# Clone the repo
git clone https://github.com/username/my-skill.git
# Copy the skill folder
cp -r my-skill ~/.codex/skills/
# Verify
cat ~/.codex/skills/my-skill/SKILL.md | head -10
```
Always check the SKILL.md before installing GitHub-sourced skills. Agensi marketplace skills are security-scanned; GitHub skills are not.
How do I add project-level skills?
For team-shared skills, put them in `.codex/skills/` in your project root:
```bash
mkdir -p .codex/skills
cp -r ~/.codex/skills/team-review .codex/skills/
git add .codex/skills/
git commit -m "add team code review skill"
```
Everyone who clones the repo gets the skill automatically.
What about the openai.yaml file?
Codex CLI supports an optional `openai.yaml` file alongside SKILL.md. This file adds Codex-specific metadata like UI hints and MCP tool dependencies. It's not part of the SKILL.md standard and other agents ignore it.
You don't need openai.yaml for skills to work in Codex CLI. The SKILL.md file alone is sufficient. The yaml file just adds optional Codex-specific features.
Can I use Claude Code and OpenClaw skills in Codex CLI?
Yes. SKILL.md is a cross-agent standard. Copy any skill from another agent's directory and it works:
```bash
# From Claude Code
cp -r ~/.claude/skills/code-reviewer ~/.codex/skills/
# From OpenClaw
cp -r ~/.openclaw/skills/test-generator ~/.codex/skills/
```
No modification needed. The core SKILL.md instructions are fully portable across all compatible agents.
For the full path reference, read Where Are Codex CLI Skills Stored?.
---
*Browse security-scanned skills for Codex CLI, Claude Code, OpenClaw, and more on Agensi.*
