[FEAT]: Support MCP Apps (SEP-1865) — Interactive UI rendering from MCP servers #3205

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opened 2026-02-28 06:33:26 -05:00 by deekerman · 0 comments

deekerman commented

2026-02-28 06:33:26 -05:00

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Originally created by @MarekFabinski on GitHub (Feb 24, 2026).

Summary

AnythingLLM already supports MCP servers as a tool client — this request is to
add support for MCP Apps (SEP-1865), the extension that allows
MCP servers to deliver sandboxed interactive UIs (HTML/JS iframes) directly
inside the chat interface.

What is it?

SEP-1865 is an official MCP extension co-authored by Anthropic and OpenAI
maintainers. It lets MCP tool servers return a
ui:// resource (rendered in a sandboxed iframe) instead of plain text,
with bidirectional JSON-RPC communication between the UI and the host.

Spec: https://modelcontextprotocol.io/community/seps/1865-mcp-apps-interactive-user-interfaces-for-mcp
Official SDK & repo: https://github.com/modelcontextprotocol/ext-apps

Use cases this unlocks

Inline forms, approval flows, and data pickers returned by agent tools
Live dashboards or results grids rendered inside the conversation
Rich outputs from connected enterprise systems (CRM, ERP, etc.)

Request

Detect ui:// resource payloads in MCP tool responses
Render them in a sandboxed iframe within the chat message area
Pass user interactions back to the agent as tool output
Works in both Desktop and Docker deployments

Originally created by @MarekFabinski on GitHub (Feb 24, 2026). ## Summary AnythingLLM already supports MCP servers as a tool client — this request is to add support for **MCP Apps (SEP-1865)**, the extension that allows MCP servers to deliver sandboxed interactive UIs (HTML/JS iframes) directly inside the chat interface. ## What is it? SEP-1865 is an official MCP extension co-authored by Anthropic and OpenAI maintainers. It lets MCP tool servers return a `ui://` resource (rendered in a sandboxed iframe) instead of plain text, with bidirectional JSON-RPC communication between the UI and the host. - Spec: https://modelcontextprotocol.io/community/seps/1865-mcp-apps-interactive-user-interfaces-for-mcp - Official SDK & repo: https://github.com/modelcontextprotocol/ext-apps ## Use cases this unlocks - Inline forms, approval flows, and data pickers returned by agent tools - Live dashboards or results grids rendered inside the conversation - Rich outputs from connected enterprise systems (CRM, ERP, etc.) ## Request - Detect `ui://` resource payloads in MCP tool responses - Render them in a sandboxed iframe within the chat message area - Pass user interactions back to the agent as tool output - Works in both Desktop and Docker deployments