What is a Claude skill?

What is a Claude skill?

A skill (also called an Agent Skill) is a capability you add to Claude, Anthropic’s AI assistant. In practice, it is a folder with a text file, SKILL.md, that describes a method: the questions to ask, what to produce and the rules to follow.

A skill doesn’t change the model or train it on your data. It is a method sheet sitting next to Claude: until it is needed, only its name and description are read. When your request matches, Claude reads the whole sheet and follows it.

A skill lets you:

• apply a method without explaining it again in every conversation;
• always get the same format: a sheet, an email, a plan, a table;
• enforce rules, for example writing “to be confirmed” instead of inventing a missing piece of information.

What does a SKILL.md file look like?

A SKILL.md file starts with a two-field header: name, the skill’s name, and description, which says when to use it. The rest of the file is the method itself, in plain text, with headings and lists.

Here is the start of a real skill, follow-ups, from the Clients Pack:

---
name: follow-ups
description: Writes follow-ups to a prospect or client who hasn't
  answered a proposal or hasn't paid an invoice, in three levels
  (gentle, firm, final). Use when the user says "they're not
  answering", "follow up", "unpaid invoice" or "no news".
---

# Follow-ups

You write polite, effective follow-ups. You write the message; you
don't calculate late fees and you don't give legal advice.

## Required information
Ask, all at once:
- Type of follow-up: unanswered proposal or unpaid invoice.
- Date of the last exchange or of the due date […]
…

The description is the most important line: it is what Claude compares with your request. The folder name must stay identical to the name line.

What is the difference between a skill, a prompt and a Project?

A prompt has to be pasted into every conversation. Personal preferences apply to all your conversations. A Project groups documents and instructions for one topic. A skill is a method for a specific task, which Claude uses on its own whenever your request matches, in any conversation.

They work together: a Project can hold a client’s context, and a skill the method for writing them a follow-up.

How does Claude know which skill to use?

Claude compares your request with the description of every installed skill. When one matches, it loads that skill, applies its method and tells you it is using it. There is no command to remember: you describe your situation in your own words.

• To pick the skill yourself, name it: “Use the follow-ups skill for this client.”
• To list installed skills, ask: “Which skills do you have available?”
• If a skill doesn’t trigger, describe a concrete situation rather than a keyword. The troubleshooting section covers the other cases.

Where do Claude skills work?

Skills work on claude.ai (in the browser and the apps) and in Claude Code, with a Claude plan that supports them. Terms may change: check Anthropic’s current plans.

• claude.ai: upload the skill’s zip in Settings › Capabilities › Skills. Code execution must be turned on. On a Team or Enterprise plan, an administrator may need to allow skills.
• Claude Code: copy the skill’s folder into ~/.claude/skills/ for all your projects, or into .claude/skills/ for a single project.
• For developers: skills can also be used with Anthropic’s API (see its documentation).

Every step is in the installation guide, for Mac, Linux and Windows.

Should you write your own skills or use a pack?

You can write your own skills: it is a text file, in a public format. A pack saves you the writing and the trial and error: the methods are already written, with the questions to ask, the format to produce and the rules to follow.

Are there ready-made Claude skill packs?

Yes. MethodoSkills-AI offers 51 skills in 10 packs, one per need, written in English and also available in French. Claude replies in the language of your conversation.

• Clients PackFind, propose, follow up
• Content PackStay visible
• Organization PackRun your day-to-day
• First Steps PackGo freelance
• Job Search PackFrom resume to offer
• E-commerce PackSell online
• Students PackRevise and present
• Managers PackTalk to your team
• Everyday Life PackLetters, quotes, budget
• Nonprofits PackVolunteer paperwork

Frequently asked questions.