What are Agent Skills?

Agent Skills are folders of instructions and scripts that teach Claude and other AI agents how to do a task your way, loaded only when needed.

An Agent Skill is a folder with a SKILL.md file that teaches an AI agent how to do one kind of task. The agent reads only the skill's name and description until a task needs it, then loads the full instructions and any scripts.

Also called Claude Skills, Agent Skill, SKILL.md, Anthropic Agent Skills.

A skill is a playbook the AI keeps on the shelf. It is a folder with one required file, SKILL.md, which holds a short name and description at the top and plain instructions below. The folder can also hold scripts, templates and reference files.

Skills load in three steps, which Anthropic calls progressive disclosure:

At start-up the agent reads only each skill's name and description, about 100 tokens per skill.
When your request matches a description, it reads the full SKILL.md.
While it works it opens extra files or runs bundled scripts only if the instructions point to them. A script's code never enters the chat; only its output does.

That is why you can install dozens of skills without slowing the AI down. It is also why the description matters most: it decides when the skill fires.

Anthropic launched Skills in Claude on October 16, 2025, and published the format as an open standard in December 2025 at agentskills.io. In October 2026 Agent Skills became a project of the Linux Foundation's Agentic AI Foundation, alongside MCP. Other agents read the same format, and OpenAI's ChatGPT and Codex plugins can bundle skills too.

Related:Model Context Protocol (MCP)SubagentsSlash commands

Agent Skills let you teach an AI agent a task once and reuse it in every chat. You write the steps in a SKILL.md file, and Claude picks the skill up on its own when your request matches. The one thing to know first: a skill can run code, so only install skills from people you trust and read them before you do.

Claude already ships with skills for Word, Excel, PowerPoint and PDF files. You can add your own in Claude Code by dropping a folder into ~/.claude/skills/, or in the Claude app by uploading a zip in Customize > Skills on any plan, Free through Enterprise, with code execution turned on. Skills you add in one place do not copy to the others. Browse ready-made ones in our skills directory, or follow how to install Claude skills and how to create one.

Good for

Anyone who keeps pasting the same instructions into Claude
Developers using Claude Code, Codex or other coding agents
Teams that want reports, decks or reviews done the same way every time
People who want Claude to make Word, Excel, PowerPoint and PDF files

Comparison

Use a skill to teach the AI how you want a task done, and an MCP server to give it access to an app. Use a plain prompt for one-off requests.

Option	What it is	Loads	Runs code	Reaches your apps
Agent SkillThis page	Instructions folder	When relevant	Bundled scripts	No
MCP server	Connector program	When connected	Yes	Yes
Prompt	Chat text	Every time pasted	No	No

Code

SKILL.md

---
name: weekly-report
description: Writes the team's weekly status report. Use when the user asks for a weekly report, status update or Friday summary.
---

# Weekly report

## Steps
1. Ask which week and which team, if not given.
2. Group the work into Shipped, In progress and Blocked.
3. Keep each item to one line, with the owner's name.
4. End with the top risk for next week.

## Example
Shipped: Login page redesign (Ana)

Our example skill. The name must match the folder and use lowercase letters, numbers and hyphens.

Often compared with

Model Context Protocol (MCP)
Subagents
Slash commands

Questions

What are Agent Skills?

Folders of instructions, scripts and files that teach an AI agent how to do one task. Each has a SKILL.md file, and the agent loads it only when your request calls for it.

How do Claude skills work?

Claude reads every skill's short description at the start. When you ask for something that matches, it reads that skill's full instructions and runs any scripts it points to. Skills you never use cost almost nothing.

Are Claude skills just prompts?

Not quite. The instructions are text like a prompt, but a skill loads by itself when it is relevant, can carry scripts and reference files, and stays available across chats. A prompt has to be pasted into each chat.

When did Claude skills come out?

Anthropic launched Skills on October 16, 2025. It published the format as an open standard in December 2025, and the Agentic AI Foundation took it on as a project in October 2026.

What is the Agent Skills standard?

An open format, documented at agentskills.io, that any agent can read. It sets the folder layout and the SKILL.md header: a name of up to 64 lowercase characters and a description of up to 1,024 characters.

What is the difference between Agent Skills and MCP?

MCP connects an AI to outside apps and data, like your Notion or GitHub. A skill teaches the AI how to do a task, like writing a report in your format. They work well together: a skill can explain how to use an MCP server.

Which plans can use skills in Claude?

Every plan, Free through Enterprise, once code execution is turned on. In the Claude app you turn skills on and upload your own in Customize > Skills. Claude Code reads skills from folders on your computer, and the Claude API needs the code execution tool.

Do skills sync between Claude, Claude Code and the API?

No. A skill uploaded to the Claude app is not available in the API or Claude Code, and the reverse. Add it separately in each place you use it.

Are Agent Skills safe?

Only as safe as their author. A skill can tell Claude to run code or call tools, so a bad one could leak data. Anthropic advises using skills you wrote or got from Anthropic, and reading every file in any other skill first.

Can ChatGPT or other agents use skills?

Yes. The format is open and many agents read it. OpenAI's plugins for ChatGPT and Codex can include skills next to an MCP server.

Sources

Docs, issue trackers and discussions this page is built from.

Show all 8

Agent Skills Overview · agentskills.io
Introducing Agent Skills · claude.com
Specification · agentskills.io
Agent Skills · platform.claude.com
Agentic AI Foundation Announces Four New Projects · aaif.io
Plugins quickstart · developers.openai.com
Use skills in Claude · support.claude.com
What is the Model Context Protocol (MCP)? · modelcontextprotocol.io