Claude Skills vs Custom GPTs vs Projects: Which to Use
2026-10-30
Short answer: a Claude Skill teaches Claude how to do one kind of task, and Claude loads it in any chat when your request matches. A Project, in Claude or ChatGPT, is a workspace that keeps files, instructions and chats together for one body of work. A custom GPT is a separate assistant you switch to, and OpenAI is retiring custom GPTs in favour of plugins, which carry skills.
This guide is for people who use Claude or ChatGPT in the browser or app, not in a terminal. It covers five things: Claude Skills, Claude Projects, ChatGPT custom GPTs, ChatGPT Projects and ChatGPT's own skills. Every claim comes from Anthropic's or OpenAI's own docs and help centers, as of Oct 30, 2026.
The five, one at a time
Claude Skills
What it is: a folder with a SKILL.md file of instructions, plus optional files and scripts. In Anthropic's words, Skills teach Claude how to do something.
What it keeps: the instructions and any files you bundle. Until a request matches, Claude sees only the skill's name and description. Then it reads the rest.
Who can use it: Anthropic's help center lists Free, Pro, Max, Team and Enterprise plans, with code execution and file creation turned on. You upload a skill as a zip file. Claude uses it automatically when it fits, or you call it with / or the + button.
Sharing: on Team and Enterprise, you can share a skill with specific people (they get view-only access and receive your updates) or publish it to your organisation. Owners can provision skills for everyone. On other plans, each person uploads their own.
Limits: a skill's name can be up to 64 characters and its description up to 1,024. Skills you upload to claude.ai don't carry over to Claude Code or the API.
Claude Projects
What it is: a self-contained workspace with its own chat history and knowledge base.
What it keeps: files you add for Claude to refer to, project instructions (such as a tone or a role to take), and the chats inside the project. Anthropic's comparison lists a project as always loaded inside that project.
Who can use it: all plans. Free users can create up to five projects. On paid plans, when a project's knowledge nears its context limit, Claude switches to retrieval (RAG), which Anthropic says can expand capacity by up to 10 times.
Sharing: on Team and Enterprise, with specific people or the whole organisation, as Can view or Can edit.
ChatGPT custom GPTs
What it is: a separate version of ChatGPT with its own instructions, knowledge files and optional actions, which you open and chat with.
Status: being retired. OpenAI's help center says existing GPTs stay usable until the retirement date. In affected Enterprise workspaces (except FedRAMP), new GPT creation ended on Oct 26, 2026. The standard retirement date is Dec 11, 2026, with Feb 11, 2027 for FedRAMP workspaces and Enterprise workspaces with a qualifying, approved deferral. At retirement, custom GPTs and their GPT pages become inaccessible. Past conversations stay accessible.
Migrating: OpenAI's replacement is a plugin. Migration turns the GPT's instructions into a skill and brings over its knowledge files and connected apps. The selected model doesn't carry over, custom actions must be rebuilt, conversation starters don't transfer one-to-one, and the new plugin starts private. After migration, the original GPT becomes read-only.
ChatGPT Projects
What it is: like a Claude Project, a workspace with its own instructions, files and chats.
What it keeps: files, instructions and chats for one body of work. OpenAI's Projects help article lists the file limits for each plan and the memory options, including project-only memory, which keeps a project's chats from drawing on conversations outside it.
Sharing: you can share a project with collaborators; OpenAI's Projects help article covers who can share on each plan.
ChatGPT skills and plugins
OpenAI confirms that ChatGPT has skills in the same SKILL.md format Codex uses. Its help center lists Skills in ChatGPT for eligible Business, Enterprise, Healthcare and Edu users. Plugins bundle skills and apps, and OpenAI's docs say plugin skills work in ChatGPT on the web, desktop and mobile. What you can install depends on your plan and workspace.
Like Claude, ChatGPT can pick a skill automatically when its description matches, or you can call one with an @ mention. OpenAI notes that an installed skill won't run on every request.
Side by side
| Claude Skill | Project (Claude or ChatGPT) | Custom GPT | |
|---|---|---|---|
| What it is | How to do one kind of task | A workspace for one body of work | A separate assistant |
| What it keeps | Instructions, files, scripts | Instructions, files, its own chats | Instructions, knowledge files, actions |
| When it's used | Any chat, when your request matches, or when you call it | Every chat inside the project | Only when you open it |
| Sharing | Team and Enterprise | Claude: Team and Enterprise. ChatGPT: collaborators | Being replaced by plugins |
| Status, Oct 30, 2026 | Available | Available | Retiring, standard date Dec 11, 2026 |
When to use which
Use a skill for a method you repeat across different work: your weekly report format, your house style for client emails, how you check an invoice. You write it once and it turns up wherever the task does.
Use a project for one ongoing piece of work with its own material: a client, a book, a grant application. The files and instructions are there in every chat in that project, and nowhere else.
Use both when you have both. Anthropic describes skills as working in any conversation and any project, so a project can hold the client's documents while a skill holds the way you write the report.
If you rely on a custom GPT, plan its move now. Check when migration is available for your account under My GPTs, then test the new plugin against the prompts you use most, because the model and custom actions don't carry over.
If your GPT's instructions are mostly a method, they can also become a Claude Skill: put the instructions in a SKILL.md, write a description saying when to use it, add the files, zip the folder and upload it. Or start from a skill someone has already published. You can search Skill Store 33 by the task, and each skill page shows its source, licence and verification state.
Gemini users have the same choice coming: Google is turning Gems into skills, starting Nov 17, 2026 for personal accounts. Our guide to which AI tools support agent skills has the details.
For how skills compare with tools for coders, see our guide to agent skills vs MCP servers vs prompts.
FAQ
Are Claude Skills the same as custom GPTs?
No. A custom GPT is a separate assistant you open and chat with. A Claude Skill is a set of instructions and files that Claude loads inside any chat when your request matches it, and several skills can work together.
Is OpenAI getting rid of custom GPTs?
Yes. OpenAI's help center says it is retiring custom GPTs and moving their creators to plugins. The standard retirement date is Dec 11, 2026, with later dates for FedRAMP workspaces and some approved Enterprise deferrals. Past chats stay accessible.
Can I use a skill inside a Claude Project?
Yes. Anthropic describes Projects as always-on context for one body of work, and skills as capabilities that work in any conversation or project. A project can hold the files and a skill can hold the method.
Can I share a Claude Skill with my team?
On Team and Enterprise plans, yes. You can share a skill with specific people or publish it to your organisation, and owners can provision skills for everyone. On other plans, each person uploads skills to their own account.
Let your agent search Skill Store 33
Skill Store 33 runs a public MCP server at https://mcp.ss33.ai. Connect it once and your agent can search about 60,000 skills by task, read what each one does, and fetch the one that fits. In Claude Code, run:
claude mcp add --transport http skill-store https://mcp.ss33.ai
Without an account your agent gets 5 searches a minute. A free account gives you a key with 60 searches a minute: create one on your account page, then add it to the connection as an Authorization: Bearer <key> header.
Sources
Anthropic, Agent Skills overview: https://platform.claude.com/docs/en/agents-and-tools/agent-skills/overview (read Oct 30, 2026)
Claude Help Center, Use skills in Claude: https://support.claude.com/en/articles/12512180-using-skills-in-claude (read Oct 30, 2026)
Claude Help Center, What are projects?: https://support.claude.com/en/articles/9517075-what-are-projects (read Oct 30, 2026)
Anthropic, Skills explained: How Skills compares to prompts, Projects, MCP, and subagents: https://claude.com/blog/skills-explained (read Oct 30, 2026)
OpenAI Help Center, Custom GPT retirement and migration FAQ: https://help.openai.com/en/articles/20001519-custom-gpt-retirement-and-migration-faq (Oct 30, 2026)
OpenAI, Moving your custom GPT workflows to plugins: https://learn.chatgpt.com/docs/migrate-custom-gpts (read Oct 30, 2026)
OpenAI Help Center, Projects in ChatGPT: https://help.openai.com/en/articles/10169521-projects-in-chatgpt (Oct 30, 2026)
OpenAI Help Center, Skills in ChatGPT: https://help.openai.com/en/articles/20001066-skills-in-chatgpt (Oct 30, 2026)
OpenAI, Build skills: https://learn.chatgpt.com/docs/build-skills (read Oct 30, 2026)
Gemini Apps Help, About the transition from Gems to skills: https://support.google.com/gemini/answer/18560919 (read Oct 30, 2026)
This article was created with the help of AI (AI-Assisted). Every product claim was checked against the official docs in the Sources list. ReadyAI is accountable for the content.