Today we’re introducing the proposal for the MCP Apps Extension (SEP-1865) to standardize support for interactive user interfaces in the Model Context Protocol. This extension addresses one of the most requested features from the MCP community and builds on proven work from MCP-UI and OpenAI Apps SDK - the ability for MCP servers to deliver interactive user interfaces to hosts. MCP Apps Extension introduces a standardized pattern for declaring UI resources, linking them to tools, and enabling bidirectional communication between embedded interfaces and the host application. ...

The MCP Bundle format (MCPB) is now part of the Model Context Protocol project. This distribution format simplifies how developers package and share local MCP servers, enabling users to install them across any compatible client, including the Claude desktop app, Claude Code, and MCP for Windows. What are MCP Bundles? MCP Bundles are ZIP archives containing a local MCP server and a manifest.json that describes the server and its capabilities. The format is similar to Chrome extensions (.crx) or VS Code extensions (.vsix), enabling end users to install local MCP servers with a single click. ...

Many of us are still exploring the nooks and crannies of MCP and learning how to best use the building blocks of the protocol to enhance agents and applications. Some features, like Prompts, are frequently implemented and used within the MCP ecosystem. Others may appear a bit more obscure but have a lot of influence on how well an agent can interact with an MCP server. Server instructions fall in the latter category. ...

Update (November 11, 2025): The specification release candidate (RC) date has been shifted from November 11th to November 14th, 2025. The specification release date remains to be November 25th, 2025. Release Timeline The next version of the Model Context Protocol specification will be released on November 25th, 2025, with a release candidate (RC) available on November 11th, 2025. We’re building in a 14-day RC validation window so client implementors and SDK maintainers can thoroughly test the protocol changes. This approach gives us the focused time we need to deliver critical improvements while applying our new governance model to the process. ...

Today, we’re launching the Model Context Protocol (MCP) Registry—an open catalog and API for publicly available MCP servers to improve discoverability and implementation. By standardizing how servers are distributed and discovered, we’re expanding their reach while making it easier for clients to get connected. The MCP Registry is now available in preview. To get started: Add your server by following our guide on Adding Servers to the MCP Registry (for server maintainers) Access server data by following our guide on Accessing MCP Registry Data (for client maintainers) Single source of truth for MCP servers In March 2025, we shared that we wanted to build a central registry for the MCP ecosystem. Today we are announcing that we’ve launched https://registry.modelcontextprotocol.io as the official MCP Registry. As part of the MCP project, the MCP Registry, as well as a parent OpenAPI specification, are open source—allowing everyone to build a compatible sub-registry. ...