OpenAI Codex Adds Official Skills Support, Echoing Claude’s Open Agent Standard

Codex Skills Overview

Codex Skills are reusable components that bundle Instructions , Scripts , and Resources . They enable Codex to perform specific workflows such as reading Linear tasks, converting PDFs to Markdown, or analyzing database schemas. Skills conform to the open Agent Skills standard.

Standard Skill Layout

SKILL.md

– metadata (name, description) and the instruction set. scripts/ (optional) – executable scripts. references/ (optional) – documentation or reference material. assets/ (optional) – templates or other resources.

Execution Model

Codex uses a progressive disclosure mechanism: at startup it loads only the names and descriptions of all available Skills, conserving tokens. The full instruction set is fetched only when a Skill is invoked.

Skills can be invoked:

Explicit call – reference a Skill in the prompt with the $ prefix (e.g., $skill-name) or via the /skills command.

Implicit call – Codex automatically activates a Skill when the task description matches the Skill’s description.

Skill Scope Hierarchy

REPO level – $CWD/.codex/skills for project‑specific Skills.

REPO ROOT level – shared Skills for the whole repository.

USER level – ~/.codex/skills for personal tools usable across projects.

SYSTEM level – built‑in Skills shipped with Codex.

Built‑in System Skills

$skill-installer

– installs Skills from GitHub. Example to add Linear support:

$skill-installer linear

$skill-installer notion-spec-to-implementation

– generates implementation code from a Notion API spec. $skill-creator – guides the user to create a SKILL.md file and optional scripts. $plan – performs research, produces a detailed execution plan, then carries out the steps.

GitHub Copilot Support

GitHub Copilot now supports Agent Skills. Skills placed in a repository’s .claude/skills directory are automatically recognized by Copilot, allowing the same Skill set to be used with Claude Code, Codex, and Copilot.

"If you’ve already set up skills for Claude Code in the .claude/skills directory in your repository, Copilot will pick them up automatically."

Current Copilot Skill coverage includes:

Copilot Coding Agent

Copilot CLI

Agent mode in VS Code Insiders (full VS Code support slated for January)

Remaining Inconsistencies

User‑level Skill directories differ: Claude Code uses ~/.claude/skills while Codex uses ~/.codex/skills. Installation conventions also vary across AI tools; the Agent Skills standard aims to unify these differences.