Do ChatGPT, Claude, Gemini and Copilot all support skills now?
Yes. As of October 2026, ChatGPT, Claude, Gemini and Microsoft 365 Copilot Cowork all read the same SKILL.md format, so the real difference between ChatGPT skills and Claude skills is not the file but the app around it: who gets skills, how you add and share them, and what limits apply.
The format is the open Agent Skills standard: a folder with a SKILL.md file holding a name, a description and instructions, plus optional scripts and reference files. Claude, ChatGPT and Gemini all document loading only the name and description at first and reading the rest when a request matches. That's why one well-written skill can work across apps.
This page compares them. For step by step guides, see Claude Skills, ChatGPT skills and Gemini skills.
How do the four compare side by side?
Each row comes from the vendor's own docs, linked in the sections below, read on 28 October 2026.
| Claude | ChatGPT | Gemini app | Copilot Cowork | |
|---|---|---|---|---|
Reads SKILL.md |
Yes | Yes | Yes | Yes |
| Add your own | Upload a .zip in Customize, Skills | Skills, Create, upload from your computer; or ask skill-creator | Upload SKILL.md, a folder or a .zip; or create in the app |
Customize, Skills: create, or upload .md, .zip or .skill |
| Where skills live | Your Claude account; separate copies for Claude Code and the API | Your ChatGPT workspace, and in plugins | Customize, Skills in Gemini | OneDrive /Documents/Cowork/skills/<name>/ |
| Runs on its own when relevant | Yes | Yes | Yes, for active skills | Yes, found at session start |
| Call by hand | Name the skill in your request | Type @ |
Type / (moving to @) |
Not covered here |
| Sharing | Team and Enterprise: with colleagues; groups on Enterprise (help center; see note below) | Only you or specific people; admins control publishing | Coming, per Google | With specific users in your organization |
| Upload check | Optional content scanning on Enterprise | Scanned before use; may be marked Needs Review or Blocked | Not described | Automatic quality and safety report |
| Download or export | Not covered here | Not covered here | More, Download as .zip | It's a file in your OneDrive |
"Not covered here" means the vendor's help pages we read didn't describe it, not that the feature is missing. One caveat on Claude: the help center describes sharing on Team and Enterprise, while Anthropic's developer overview still says claude.ai custom skills are individual to each user. Check your own plan's settings.
Which plans can use skills in each app?
| App | Who gets skills, per the vendor |
|---|---|
| Claude | Free, Pro, Max, Team and Enterprise, with code execution turned on |
| ChatGPT | Eligible Business, Enterprise, Healthcare and Edu users, subject to workspace settings |
| Gemini app | People 18 and over on a personal Google Account with Keep Activity on; no Google AI subscription listed |
| Copilot Cowork | Work or school accounts (generally available); personal accounts in preview |
The sources: Anthropic's Use skills in Claude article (its developer docs list custom skill uploads on Pro, Max, Team and Enterprise); OpenAI's Skills in ChatGPT help article; Google's create and manage skills and Gems transition pages; and Microsoft's Copilot Cowork overview.
What are the limits in each app?
| Limit | Claude | ChatGPT | Gemini app | Copilot Cowork |
|---|---|---|---|---|
| Number of skills | Not stated in the app; up to 20 per API request | Not stated | Unlimited, 100 active | 50 custom skills |
| Size | API: 30 MB per skill, uncompressed | API: 50 MB per zip, 25 MB per file, 500 files | 100 MB per skill | SKILL.md up to 1 MB; 20 companion files; 10 MB per skill |
| Name | Up to 64 characters, lowercase, digits, hyphens | Agent Skills spec | Lowercase with hyphens | Name and description required |
| Description | Up to 1,024 characters | Agent Skills spec | Up to 1,024 characters | Too long and the skill never loads |
| Network for scripts | App: depends on settings; API: none | Not described for the app | No internet access | Not described |
Claude's limits come from its Agent Skills overview and Skills API guide; OpenAI's from its API skills guide; Copilot's from Use Copilot Cowork.
Can you move one SKILL.md between them?
Yes. Each app has a documented way in:
- Claude: zip the skill folder, then upload the .zip in Customize, Skills.
- ChatGPT: upload it from the Skills page. OpenAI's Build skills docs say its skills "build on the open agent skills standard."
- Gemini: upload the
SKILL.md, a folder or a .zip from gemini.google.com or the Mac app. Google says you can import skills made on other platforms this way. - Copilot Cowork: upload a .md, .zip or .skill file from Customize, or put the folder in OneDrive under
/Documents/Cowork/skills/.
Inside Claude itself, skills don't sync everywhere either. Anthropic's docs say skills uploaded to claude.ai must be uploaded to the API separately. Anthropic's help center adds that recent versions of Claude Code load the skills you've enabled in claude.ai when you sign in with the same account.
What breaks when a skill moves to another app?
The format travels; the content sometimes doesn't. Check these before you rely on a moved skill:
- Scripts that need the internet. Gemini blocks them and Claude's API container has no network access.
- Tool names. "Run this terminal command" means something in Claude Code and nothing in the Gemini app. Write instructions that describe the goal, not one app's tool.
- File types. Gemini rejects .docx and .xlsx reference files. Markdown, CSV and PDF are the safe choices.
- Names. Claude's rules are strict: lowercase letters, digits and hyphens, up to 64 characters, matching the folder, and not containing "anthropic" or "claude". A name that passes Claude's rules is the safest choice for the other apps too.
- App-only extras. OpenAI reads an optional
agents/openai.yaml, and Claude Code reads extra header fields. Don't rely on them outside the app that defines them.
What happens to GPTs and Gems that become skills?
Both older formats are being folded into skills:
| Custom GPTs (OpenAI) | Gems (Google) | |
|---|---|---|
| Becomes | A plugin; the instructions become a skill | A skill |
| Key date | Retire December 11, 2026 | Read-only 17 November 2026, removed 17 December 2026 (personal accounts) |
| Other dates | Follow your workspace's own notice, per OpenAI's admin docs | Workspace business March 2027, education June 2027 |
| What doesn't carry over | Custom actions, the selected model, conversation starters | Files over 100 MB, audio, video, archives, older Office files |
The OpenAI dates are from its retirement FAQ and migration guide; our custom GPTs guide has more. The Google dates are from the Gems transition FAQ. Projects are a separate feature in both ChatGPT and Claude; see ChatGPT Projects vs Claude Projects.
Which should you use?
Pick by where you already work, not by the skill format, since the format is shared:
- Claude if you also use Claude Code or the API and want the same skills on your desktop and in your terminal.
- ChatGPT if your company runs on a ChatGPT Business, Enterprise or Edu workspace and you want admins to control sharing.
- Gemini if you want skills on a personal Google account (Google lists no subscription requirement), or you're moving Gems before the deadline.
- Copilot Cowork if your work lives in Outlook, Teams and OneDrive and you want skills that act on it.
Where should you keep the master copy of your skills?
Outside any one app. Every vendor above stores your skills in its own account, workspace or folder, and GPTs and Gems show that those can change on the vendor's schedule. Kipt keeps your prompts and skills as Markdown in a private GitHub repo you own, imports skills from a GitHub link, a folder or a .zip, and installs every skill into Claude Code or Codex with npx skills add https://github.com/<you>/<repo>.git --all -g. From that one copy you can upload the same SKILL.md to each app above.