Copilot Cowork Skills: What They Are and How to Create Your Own
Skills are what make Copilot Cowork actually useful. They're the capabilities Cowork draws on to complete your tasks, from drafting emails to building PowerPoint decks to doing deep research. Some are built in, and you can create your own to teach Cowork how *you* work.
Think of skills as specialized instructions. Built-in skills handle common tasks. Custom skills teach Cowork your preferences, your processes, or your domain expertise.
What are skills in Copilot Cowork?
A skill is a set of instructions that tells Cowork how to do something. When you ask Cowork to summarize your inbox or build a slide deck, it loads the relevant skills automatically and uses them to complete the task. You can see which skills are active in the side panel while Cowork works.
There are three types of skills:
- Built-in skills ship with Cowork and cover common tasks like email, documents, and scheduling.
- Custom skills are ones you create to teach Cowork your preferences or processes.
- Plugin skills come from plugins you add from the Microsoft 365 App Store.
Built-in skills
Cowork comes with 13 built-in skills that cover the most common work tasks:
| Skill | What it does |
|---|---|
| Word | Creates and edits Word documents |
| Excel | Builds spreadsheets, analyzes data, creates charts |
| PowerPoint | Builds and edits slide decks |
| Reads and extracts information from PDFs | |
| Drafts, sends, and manages Outlook emails | |
| Scheduling | Books meetings and manages invites |
| Calendar Management | Organizes your calendar, finds free time, resolves conflicts |
| Meetings | Prepares agendas, summarizes past meetings, tracks action items |
| Daily Briefing | Summarizes your day: what's coming, what needs attention |
| Enterprise Search | Finds information across your organization's data |
| Communications | Drafts messages for Teams, announcements, newsletters |
| Deep Research | Does multi-source research with citations |
| Adaptive Cards | Creates interactive cards for Teams and Outlook |
You don't need to turn these on. Cowork loads them automatically based on what your task needs.
Why create custom skills?
Built-in skills are generic. Custom skills make Cowork work the way *you* work. Some examples:
- Email voice skill teaches Cowork your writing style so drafts sound like you, not a robot.
- Design skill captures your team's visual style (colors, fonts, layouts) for decks and documents.
- Business process skill encodes how you run a specific workflow (monthly close, client onboarding, etc.) so Cowork can run it the same way every time.
- Customer requests skill scans meeting transcripts, Teams chats, notes, and emails for customer feature requests.
- Leadership status update skill drafts concise, skimmable status updates for leadership with progress, risks, and asks.
- Skeptic skill pressure-tests a request for clarity before Cowork acts, so the work is high-quality on the first try.
In Microsoft's GA demo, Charles Lamanna showed an email voice skill he built using Cowork itself. It learned from his last 2,000 sent emails and gets more personalized the more he uses it.
How to create a custom skill
There are four ways to create a custom skill:
Option 1: Use the guided flow
- Open Cowork and select Customize in the left navigation.
- Go to the Skills tab.
- Click Create new.
- Cowork walks you through writing the skill in a conversation. Describe what you want the skill to do, and it helps you write the instructions.
- Give it a name and description, then save.
Option 2: Drag and drop
If you already have a skill file (.md, .zip, or .skill), just drag and drop it into the Skills tab. Cowork uploads and validates it automatically.
Option 3: Ask Cowork to build it
You can ask Cowork directly in chat:
Prompt
Create a personal skill that captures how I write emails. Learn my tone, greetings, and sign-off from my sent messages, and use that style whenever you draft emails for me. Save it as a reusable skill.
Cowork builds and saves the skill for you.
Option 4: Write a SKILL.md file
For full control, create a SKILL.md file manually and upload it or save it to OneDrive.
The SKILL.md format
A skill file is a Markdown file with YAML frontmatter. Here's the structure:
---
name: Email Voice
description: Use this skill when drafting emails to match my personal writing style.
---
When drafting emails for me:
- Use a warm but professional tone
- Start with "Hi [name]," not "Dear"
- Keep paragraphs short (2-3 sentences max)
- End with "Best," followed by my name
- Avoid corporate jargon like "synergy" or "circle back"
The frontmatter requires two fields:
- name is what the skill is called (shows up in the Skills tab).
- description is when Cowork should use this skill. This is important: a good description helps Cowork pick the right skill for each request.
Everything after the frontmatter is the instructions. Write them like you're explaining to a smart colleague.
File limits
| Type | Limit |
|---|---|
| Single .md file | 1 MB |
| Archive (.zip or .skill) | 10 MB compressed, 50 MB uncompressed |
| Files per archive | 100 files |
| Total custom skills | 50 |
If your skill needs companion files (templates, reference docs, examples), bundle them in a .zip or .skill archive with the SKILL.md at the root.
Where skills are stored
Custom skills sync to your OneDrive at /Documents/Cowork/skills/<skill-name>/. You can edit them there directly, and Cowork picks up changes on the next conversation.
Sharing skills
You can share skills with others in your organization:
- Open the skill's detail page in the Skills tab.
- Click Share in the top-right.
- Choose Specific users in your organization and add people by name or email.
- Click Apply.
You stay the owner, so any edits you make flow automatically to everyone you've shared with.
Tips for writing good skills
- Write a clear description. Explain *when* Cowork should use this skill, not just what it does.
- Be specific in instructions. Vague instructions get vague results.
- Test in a new conversation. Start fresh to see how the skill behaves without prior context.
- Turn off unused skills. In the Sources picker, disable skills you don't need to keep results focused.
- Iterate. Skills improve over time as you refine the instructions.
Managing skills in the Customize page
The Customize page (left nav → Customize → Skills tab) is where you manage all your skills:
- Your skills shows custom skills you created or added via plugins.
- Built-in shows the 13 skills that ship with Cowork.
- Search and filter to find specific skills.
- Click any skill to edit, download, share, or delete it.
The bottom line
Built-in skills handle the basics. Custom skills make Cowork work like *you* work: your tone, your processes, your preferences. Start with the guided flow or ask Cowork to build a skill for you, and iterate from there. For more on what Cowork can do, see our complete guide or browse Copilot Cowork tips.
Frequently asked questions
What are skills in Copilot Cowork?
Skills are instructions that tell Cowork how to do specific tasks. Built-in skills handle common work like email and documents. Custom skills teach Cowork your preferences, writing style, or business processes.
How many custom skills can I create?
You can create up to 50 custom skills. Each skill file can be up to 1 MB, or 10 MB if bundled as an archive with companion files.
Do I need to know how to code to create a skill?
No. You can use the guided flow in the Customize page, or just ask Cowork in chat to create a skill for you. If you want full control, you can write a SKILL.md file in Markdown, but it's not required.
Where are custom skills stored?
Custom skills sync to your OneDrive at /Documents/Cowork/skills/. You can edit them there directly, and Cowork picks up changes on the next conversation.
Can I share skills with my team?
Yes. Open a skill's detail page, click Share, and add specific people from your organization. You stay the owner, so any edits you make flow automatically to everyone you've shared with.
What's the difference between skills and plugins?
Skills are instructions that teach Cowork how to do something. Plugins connect Cowork to external systems and data sources. Plugins can include skills, but they also add connectors to outside services like Dynamics 365 or Salesforce. If you have a Claude or Open-Plugin package, Cowork auto-converts it when you upload.