Claude Code skills vs Codex skills

Both Claude Code and OpenAI Codex are skill-based agent-augmentation systems. They share a lot of concepts, and a well-authored skill can serve both. Here is how they line up.

The shared concept

A skill is a packaged instruction set with a trigger description, primary guidance (usually a SKILL.md), optional references, and optional scripts. When a user's request matches the trigger, the agent pulls the skill into context and follows it. This pattern works the same on both platforms: the agent does not memorize every task; it loads the right skill when it needs one.

Skills also travel in bundles: a collection of related skills installed as a single plugin. Bundling keeps distribution simple and makes it easier to version related skills together.

Claude Code skills

• Installed via the Claude Code plugin system. Users add a marketplace, then run /plugin install <bundle>.
• Skill metadata targeted to Claude lives inagents/claude.yaml inside each skill directory.
• The Claude Code CLI handles trigger matching, reference loading, and invocation automatically. Users rarely need to call a skill by name.
• Bundles can include hooks and slash commands alongside skills, which lets a bundle extend Claude Code behavior beyond per-request skill use.

Codex skills

• Consumed by OpenAI Codex agents (CLI and IDE surfaces). Users load skill bundles into the Codex workspace and the agent picks them up on trigger.
• Skill metadata targeted to Codex lives inagents/openai.yaml, letting a single skill directory publish both Claude and Codex frontmatter side by side.
• Codex leans on OpenAI's function-calling and tool-use primitives under the hood, so scripts inside a skill are executed through those mechanisms rather than through Claude Code's plugin host.
• Bundles install the same way in practice — one unit of distribution — but without the Claude-specific plugin subcommands.

Key differences at a glance

• Install surface. Claude Code has a native marketplace and/plugin install flow; Codex integrates skills through its own agent configuration.
• Metadata file. agents/claude.yaml for Claude Code, agents/openai.yaml for Codex.
• Extra primitives. Claude Code bundles also ship hooks and slash commands; Codex bundles focus on skills plus scripts.
• Platform model. Claude Code is a full desktop CLI with long-lived context; Codex runs inside the broader OpenAI agent stack.

How this marketplace serves both

Every skill in Alison's LLM Skills Marketplace is authored to target both platforms. Each skill directory contains its ownagents/claude.yaml andagents/openai.yaml, plus a shared SKILL.md, references, and scripts. That means one install works for Claude Code, and the same content drops into a Codex workspace without rewriting. Browse the full skill catalog or read what agent skills are if you are new to the concept.

Deciding whether to adopt a marketplace at all? See why use a skills marketplace. Ready to install? Follow the install-from-GitHub guide.

Official documentation

• Anthropic Claude Code docs: docs.claude.com
• OpenAI Codex docs: platform.openai.com/docs