Skills
Reusable instruction packs an AI agent loads only when a task calls for them. A skill is a folder with a text file inside, named SKILL.md, that explains how to do one kind of task your way, plus any files it needs. A prompt is for one chat. A skill is for every time that task comes up.
In plain English
A skill is a recipe card the agent keeps in a drawer. It doesn’t read every card every time. It skims the titles, and when a task matches, it pulls that card and follows it.2 Your way of doing the thing, written down once.
In the real world
- A
skillsfolder in a Claude Code project, one subfolder per task. - Anthropic’s own document skills, which let Claude fill PDF forms and edit spreadsheets.1
- A “brand voice” skill so every draft sounds like the company instead of the model.
When to use it
- Any task you’ve explained to the AI more than twice.
- Procedures with steps and a format: reports, reviews, onboarding docs.
When not to use it
- One-off tasks. That’s a prompt.
- Facts that change weekly. A skill is a procedure, not a news feed.
Good, bad, ugly
- Good: write the procedure once, stop re-explaining it.
- Bad: someone has to write and maintain the cards.
- Ugly: a skill nobody updated, quietly applying last year’s process to this year’s work.
Key facts
- Introduced
- October 2025, by Anthropic, for Claude and Claude Code
- A skill is
- A folder with a SKILL.md text file inside, plus any files or small programs it needs
- Versus a prompt
- A prompt is for this chat. A skill is for every time this kind of task comes up.
Common questions
Do I need to code to make a skill?
No. The simplest skill is a folder with one text file describing how to do a task your way. Scripts are optional.
How does the agent know when to use one?
Each skill has a short description. The agent reads the descriptions, and loads the full instructions only when a task matches. Anthropic's docs call this loading on demand.
What's a good first skill?
The thing you explain to the AI every week. Your brand voice, your report format, your meeting-notes template.
References
- Equipping agents for the real world with Agent SkillsAnthropic Engineering · 2025-10-16View source
- Agent Skills overviewAnthropic, Claude Platform DocsView source