mcp-extensions README

The project's README from github.com/openai/mcp-extensions. As one markdown file: README.md.

OpenAI MCP Extensions

OpenAI MCP Extensions adds ChatGPT-specific capabilities to MCP so developers can build plugins that feel like native, first-class features.

Showcase

All examples below use the Bits & Bolts plugin, which you can try by installing the plugin.

Sidebar entrypoints

Allow users to access your app from the sidebar.

Opening an MCP App from the sidebar

File extension handlers

Render custom file viewers when users open a supported file type.

Opening a CAD file in a custom file viewer

Composer mentions

Let users search your plugin’s resources from the composer and add references to a message.

Searching for a CAD part with composer mentions

Extended forms

Let users select a CAD part using thumbnail choices.

Selecting a CAD part in a Bits & Bolts form

Get started

0. Try it out

Install the Bits & Bolts Remote plugin:

  1. Install Bits & Bolts Remote from the plugin directory.

  2. Select Bits & Bolts Remote in the sidebar to open the Parts Library.

    Bits & Bolts Remote selected in the sidebar with the Parts Library open

1. Create a plugin

Read the plugin documentation about how to create a plugin. Once you have a plugin…

2. Add the SDKs to your MCP server

Follow the SDK installation instructions for the current source:

3. Explore supported extensions

Read the spec to learn more about supported extensions.

License

This project is licensed under the Apache License 2.0.

mcp-extensions (openai/mcp-extensions)

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Mcp-extensions
What is this?A toolkit that adds ChatGPT-specific capabilities to the Model Context Protocol (MCP), letting plugin developers build features like sidebar entrypoints, custom file viewers, composer mentions, and rich forms that feel like native parts of ChatGPT.
Is this a standalone app or something I add to my own MCP server?It's a specification plus SDKs you add to an MCP server you already have (TypeScript: @openai/mcp-extensions, Python: openai-mcp-extensions), not a standalone application.
How do I add these extensions to my plugin?First build a basic MCP plugin following the plugin documentation, then install the matching SDK (@openai/mcp-extensions for TypeScript or openai-mcp-extensions for Python) and implement extensions from the spec.
Do I need an existing MCP server before using this?Yes, you need a working MCP plugin/server first; this package only layers ChatGPT-specific extensions on top of it.
Does this work with any MCP client, or only ChatGPT?The extensions are ChatGPT-specific — sidebar entrypoints, composer mentions, and the other showcased features are ChatGPT UI integrations, not generic MCP client behavior.
What is the Bits & Bolts plugin shown in the examples?It is the demo plugin used throughout the README to showcase each extension — a CAD parts library you can browse from ChatGPT's sidebar after installing it.
What kinds of UI extensions can I build?Sidebar entrypoints to open your app, custom viewers for specific file types, composer mentions to search your plugin's resources, and extended forms such as thumbnail-based selection fields.
Where is the full list of supported extensions documented?The README points to a spec document that lists all supported extensions in detail, referenced in the 'Explore supported extensions' step.
What are similar projects?headroom, evenfire, servers, gitagent, turnstone, aisuite, claude-context, tambo
Which topics is it in?spec, pypi, extension, plugin-system, chatgpt, model-context-protocol, sdk, mcp-server, plugin, openai, framework, agent
Creator
openai
Size
70.8 MB
Stars
1.1K
Updated
CommitOct 10Releasepython-v0.2.0Oct 10
Age
19d
Commits · 90 Days