Our verdict: Claude Skills are the most capable and the safest bet, because the other two are moving to the same shape. Heavy ChatGPT users should build a plugin, not a GPT, and Gems still make sense if your work lives in Google Drive, as long as you know they're on the way out.
Claude has Skills, ChatGPT has GPTs and Gemini has Gems. All three let you package instructions, reference files and sometimes code, then reuse them in any chat. By October 2026 they're converging: OpenAI is retiring custom GPTs in favor of plugins, and Google is turning Gems into skills.
Claude Skills
ChatGPT GPTs
ChatGPT Plugins
Gemini Gems
The move to skills, by date
Existing GPTs and Gems keep working until their dates. After that, GPT pages become inaccessible, while Gems convert into skills automatically.
The 4 options at a glance
Claude Skills- Plain files you can keep in git
- Can run scripts, not just describe steps
- Same skill works in Claude Code
The catch: writing one takes some comfort with markdown.
ChatGPT Plugins- Bundles skills and connected apps
- Built by chatting with Plugin Creator
- Shared with Codex
The catch: skills target business workspaces first.
Gemini Gems- Drive files as live knowledge
- Shows up in the Workspace side panel
- Simple name-and-instructions setup
The catch: becoming skills from November 2026.
ChatGPT GPTs- Largest library through the GPT Store
- Up to 20 knowledge files, 512 MB each
- Custom actions via your own APIs
The catch: retiring December 11, 2026.
Cost and status
Prices checked October 15, 2026, on each company's own pricing page. Status checked October 23, 2026, on each company's help pages.
| System | Cost to build | Best for | Status in October 2026 |
|---|---|---|---|
| Claude Skills | Every plan, including Free; Pro is $20/mo | Developer workflows: files, scripts, git | Active in Claude apps and Claude Code |
| ChatGPT GPTs | Business, Enterprise and Edu workspaces only for new GPTs | Using GPTs that already exist | Retiring Dec 11, 2026, in favor of plugins |
| ChatGPT Plugins (with skills) | Plugin directory on every plan; Plus is $20/mo | ChatGPT users who need a GPT replacement | New; skills generally available on Business, Enterprise, Healthcare and Edu |
| Gemini Gems | Free with a Google account; Google AI Pro is $19.99/mo | Google Drive files as knowledge | Turning into skills on personal accounts from November 2026 |
What each one can do
| Feature | Skills | Plugins | Gems | GPTs |
|---|---|---|---|---|
| Build on a personal plan | ✓ | ✓ | ✓ | ✗ |
| Can include and run code | ✓ | ✓ | ✗ | Code Interpreter |
| Works in a coding tool | Claude Code | Codex | – | ✗ |
| Share with a team | Team, Enterprise | Business, Enterprise | ✓ | ✓ |
| Live Google Drive files | – | – | ✓ | – |
| Still supported in 2027 | ✓ | ✓ | Work accounts only | Approved deferrals |
– means the company hasn't said.
Claude Skills: the most capable
A Skill is a folder: a markdown file that says what it does, plus optional reference files and scripts. Claude loads it automatically when it's relevant. Because it's just files, you can commit it to git and review changes like code.
Skills work on Free, Pro, Max, Team and Enterprise once code execution is on, and Anthropic includes built-in skills for Excel, Word, PowerPoint and PDF. Skills you turn on in claude.ai also sync to Claude Code when you sign in with the same account. A GPT can describe a workflow, but a Skill can run it.
ChatGPT: plugins replace GPTs
Personal accounts (Free, Go, Plus and Pro) can no longer create or publish new GPTs, and OpenAI plans to retire custom GPTs on December 11, 2026. Existing GPTs work until then, and your old conversations stay accessible afterward.
The replacement is plugins, which you build by chatting with Plugin Creator. A plugin can hold skills (reusable instructions, examples and code) and connected apps like Slack. A built-in migration turns a GPT's instructions into a skill and copies its knowledge files over.
Gemini Gems: best for Google Drive, for now
Gems are a name, instructions and optional knowledge files. Their edge is Google's world: add Drive files as knowledge and the Gem always reads the latest version, and Gems you make on the web appear in the Gemini side panel in Workspace apps.
Google now has skills in Gemini chat for personal accounts, and Gems on those accounts go away starting November 2026, converting to skills automatically. Workspace business customers follow in March 2027 and education in June 2027.
What about Open WebUI and LibreChat?
Open WebUI and LibreChat let you build custom personas with prompts, knowledge files and tools against any model. They take more setup and skip the platform hooks, but nothing locks you in.
Which one should you use?
The verdict
Claude Skills are the best custom AI system in 2026: plain files, real scripts and the same skill in chat and Claude Code. Pick by where you already work, though, since ChatGPT plugins and Gemini skills are copying the format.
FAQ
What are Claude Skills?
Claude Skills are reusable, file-based packages of instructions, scripts and reference material that extend Claude's behavior. They work on every Claude plan, including Free, when code execution is on, and they also work in Claude Code. Unlike GPTs, Skills can include executable code.
What's the difference between Claude Skills and ChatGPT GPTs?
GPTs are built in a wizard inside ChatGPT, but personal accounts can no longer create new ones, and OpenAI plans to retire custom GPTs on December 11, 2026, in favor of plugins. Claude Skills are files you can version in git, they work across Claude apps and Claude Code, and they can run scripts. ChatGPT plugins with skills are OpenAI's closest match to Claude Skills.
Are Gemini Gems useful?
Yes, if you live in Google Workspace. You can add Google Drive files as knowledge and the Gem always reads the latest version. But Google is turning Gems on personal accounts into skills starting in November 2026, with work accounts following in 2027, so treat them as a short-term tool.
Can I share a Claude Skill with my team?
Yes. Skills are files, so you can share them through git or a shared folder. On Claude Team and Enterprise plans you can share a skill with specific colleagues or publish it to your organization, and owners can provision skills for everyone. There's no public Skills store in claude.ai, but Claude Code plugins can carry skills through plugin marketplaces.
Which custom AI system should I use in 2026?
Pick by where you live. Developer or Claude Code user: Skills. Heavy ChatGPT user: a plugin, since new GPTs are off on personal plans and custom GPTs retire December 11, 2026. Google Workspace user with data in Drive: Gems for now, knowing they become skills from November 2026. All three platforms are moving toward the same skills format.