OpenAI has published an open-source toolkit that lets developers give MCP servers features that exist only inside ChatGPT. MCP is Anthropic’s protocol for tool calling, and the new openai/mcp-extensions repository adds four hooks on top of it: sidebar entry points, viewers for particular file types, resource lookup inside the message composer, and forms that offer thumbnail choices.
The TypeScript package, @openai/mcp-extensions, covers MCP servers and Apps. The Python package, openai-mcp-extensions, covers servers only. The project uses the Apache License 2.0. A written spec lists every supported extension, and a separate patterns document collects best practices.
OpenAI’s demo plugin, Bits & Bolts, puts the forms to work: a user picks a CAD part from thumbnails inside a Parts Library. The repository does not say whether other MCP clients will recognize these extensions. That answer decides whether a plugin built this way travels beyond ChatGPT or stays tied to it, so teams should settle it before investing.
Published by OpenAI on GitHub in the openai/mcp-extensions repository.
