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 SEP was authored by MCP Core Maintainers at OpenAI and Anthropic, together with the MCP-UI creators and lead maintainers of the MCP UI Community Working Group.
Standardization for interactive interfaces#
Currently, MCP servers are limited to exchanging text and structured data with hosts. While this works well for many use cases, it creates friction when tools need to present visual information or gather complex user input.
For example, consider a data visualization MCP server that returns chart data as JSON. The host application must interpret that data and render it. Handling all kinds of specialized data in this scenario translates to a significant burden for client developers, who would need to build their own logic to render the UI. As more UI requirements come up, like the need to collect multiple related settings from users, the complexity balloons. Alternatively, without UI support, these interactions become awkward exchanges of text prompts and responses.
The MCP community has been creative in working around these limitations, but different implementations using varying conventions and architectures make it harder for servers to work consistently across clients. This lack of standardization creates a real risk of ecosystem fragmentation - something we’re working to proactively prevent.
Building together#
The MCP-UI project, created by Ido Salomon and Liad Yosef and maintained by a dedicated community, spearheaded the vision of agentic apps with interactive interfaces. The project developed patterns for delivering rich user interfaces as first-class MCP resources, proving that agentic apps fit naturally within the MCP architecture. The project is backed by a large community and provides rich SDKs, adopted at leading companies and projects such as Postman, Shopify, Hugging Face, Goose, and ElevenLabs.
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