MCP Apps (UI) support preview

Last week, the team behind MCP-UI, Anthropic, and OpenAI announced a collaboration to create MCP Apps, a new standard to bring interactive UI to MCP clients. This collaboration was inspired by the work done on the open source MCP-UI project, and OpenAI's Apps SDK announced earlier this month.

MCP Apps is still in its earliest stages. The collaboration is still in proposal phase in the @modelcontexprotocol repo as an enhancement proposal, SEP-1865. Olivier Chafik of Anthropic has been leading the initial development of the official SDK.

The MCPJam team spent this week building the first working client prototype that supports MCP Apps, and fixing up the official SDK. We're excited to have the community try out the preview.

Example in the official SDK

We recently merged a PR that fixes the build of the official SDK, and now the example MCP Apps server works. Here's how to set up the example server:

1. Clone the official SDK
2. Run npm i
3. In your terminal, navigate to the /examples/simple-server directory.
4. Run npm run build, then npm run start
5. You should see that the MCP Apps server is now starting at localhost:3001/mcp

Connect to the example MCP server on MCPJam. You should be able to view the widget metadata.

MCPJam Apps Preview

It's planned that in the near future, the frontier chat interfaces like Claude and ChatGPT will be adopting MCP Apps. As of now, there are no existing clients that support MCP Apps as the SDK and the spec is still in the works.

We built the first MCP client prototype that supports MCP Apps. MCPJam client follows the spec defined in SEP-1865 such as resource handling, tool calling, send follow up message, etc. We hope the MCPJam client preview will help with accelerating the development of the MCP Apps SDK.

This is what MCPJam looks like with the official MCP Apps example server from the SDK:

Help us accelerate MCP Apps

MCPJam is an open source MCP inspector. In addition to MCP Apps preview, we also have full support for MCP-UI and OpenAI Apps SDK.

What we currently have is a preview of what's been built in the SDK so far. The SEP is still evolving as well as the SDK. We're looking for help from the community to develop our MCP Apps support.

Having dev tools like MCPJam will help with maturing the SDK and providing a reference for future MCP client implementers to support MCP Apps.

Here's our GitHub repo: https://github.com/MCPJam/inspector

Please also consider joining our Discord community, where we have frequent discussion MCPJam and anything MCP related.