Backport MCP Apps support to older protocol versions
Author: pjmsmithgoogleCreated Sep 16, 2026Updated Sep 16, 2026
Labelstype: feature request
Prerequisites
- Search the current open issues
What are you trying to do that currently feels hard or impossible?
Recently MCP Apps support was added to mcp-toolbox but only for protocol version 2026-07-28. Not all clients have adopted version 2026-07-28 yet and support for MCP Apps is included in in "legacy" protocol versions. Gemini Enterprise is one client that communicates using version 2024-11-05 which would block any tools from displaying UI resources in Gemini Enterprise.
Suggested Solution(s)
We should backport support to older protocol versions, understanding that those versions do not have a mechanism for advertising server capabilities.
Alternatives Considered
No response
Additional Details
No response
Source: googleapis/mcp-toolbox