Short answerMCP is an open standard for connecting AI apps to outside tools and data. OpenAI says a plugin needs an MCP server when it requires live data, authentication or controlled actions, and the server defines the tools ChatGPT can use. That is the route to rebuild Actions.
What MCP is
The official introduction calls MCP an open-source standard for connecting AI applications to external systems, like a USB-C port for AI. Servers can offer tools, resources and prompts.
How OpenAI uses it for plugins
- The server defines the tools available to ChatGPT and Codex.
- It should run at a stable HTTPS endpoint supporting MCP streamable HTTP.
- OpenAI says to enforce authorization in the server for every request.
Turning an Action into an MCP tool
- List each Action operation (schema mapping).
- Implement each as a tool with a clear description and input schema.
- Handle authentication on the server.
- Connect it to a plugin and test: testing.
This is developer work. For a scoped estimate, ask for an audit.
Not sure it is simple enough to do yourself?
Tell us what your GPT does, whether it uses Actions and how many files it has. We will say what will break and what a rebuild involves. The audit is free.
Request a free auditRelated guides
Sources
- Model Context Protocol: introduction
- OpenAI docs: Build an MCP server for plugins
- OpenAI developers: Plugin architecture
Pages describing other companies' products reflect their public documentation on the date shown and can go out of date.