Claude Skills are folders of instructions, and sometimes scripts and templates, that Claude opens up when a task calls for them. Instead of explaining your formatting preferences or a document style every single time, you save that knowledge once as a skill, and Claude reaches for it automatically when it's relevant.
If you've noticed "Skills" under Customize in Claude or Cowork and weren't sure what it meant, here's the plain-English version: what skills do, the ones Claude already comes with, and how to turn one on or build your own.
The quick answer
A skill is a folder with an instructions file, called SKILL.md, at minimum. Many skills also include scripts, reference documents, or templates alongside it. Claude reads each skill's short description first, and only opens the rest of the folder when your request matches what that description says the skill is for. That's the whole mechanic: a description that tells Claude when to use something, and a folder that tells Claude how.
Why this matters if you're new to Claude
Without skills, every conversation starts from zero. If you want Claude to build a spreadsheet the way your team formats them, or write in a specific tone, you'd normally explain that from scratch each time, or paste the same reference material into the chat over and over.
A skill fixes that. You save the instructions once. Claude checks its available skills at the start of a task, matches your request against each one's description, and loads the right one on its own. There's no command to type to trigger it. You ask for the thing you want, and Claude notices a skill applies.
The skills Claude already comes with
Anthropic ships several skills by default, covering some of the most common document requests: better Excel spreadsheets, professional Word documents, PowerPoint presentations, and PDF creation and editing. These need Code execution and file creation turned on to run. Once that's on, ask Claude to build a PowerPoint about your Q3 results, and it reaches for the PowerPoint skill without you naming it.
How to turn skills on
- Go to Settings > Capabilities (Free, Pro, and Max plans) or Organization settings > Skills (Team and Enterprise), and turn on Code execution and file creation. Skills won't run without it.
- Open Customize > Skills to see your full list.
- Toggle individual skills on or off. Disabled skills stay out of Claude's reach until you switch them back on.
Building your own skill
You're not limited to Anthropic's defaults. If you keep asking Claude to do something a specific way, a report format, brand guidelines, a recurring analysis, you can package those instructions into your own skill. At minimum that's one SKILL.md file with a short description and the steps to follow, zipped into a folder and uploaded through Customize > Skills.
The description matters most. Claude scans every skill's description to decide whether it applies to what you just asked, so a vague one means Claude never finds it. "Use for formatting reports" is weak. "Use when creating monthly sales reports for the leadership team: formats revenue by region and flags anything down more than 10%" gets triggered when it should, because it names the exact situation.
Sharing skills with a team
On Team and Enterprise plans, you can share a skill you've built with specific colleagues or your whole organization, and admins can provision skills so they show up for everyone automatically. Recipients get a view-only copy. They can turn it on and use it, but not edit the contents, and if you update the original later, everyone using it gets the update automatically.
Should you build one?
If you're brand new to this, start with the skills Anthropic already turned on. Pay attention to when you're repeating the same instructions or reference material across conversations. That repetition is the signal a skill would help. Anthropic's own advice for getting started: begin with the pre-built skills, then write your own once you understand how they trigger.
Skills and a CLAUDE.md file solve a related problem in different ways. A CLAUDE.md file loads every single session in a project, so it works best short and universal. A skill loads only when it's relevant, which keeps a specific format or workflow out of the way until it's needed. If you're setting up a coding project with Claude, how to write a CLAUDE.md file covers the other half of that setup. And if you're still getting oriented in Cowork generally, our beginner's guide to Claude Cowork is the place to start.
Sources:
support.claude.com, "Use skills in Claude" ·
claude.com/blog, "Lessons from building Claude Code: How we use skills"
