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When is 2025-11-25 protocol version support expected? #800
Downstream MCP servers built with rmcp cannot surface tools in Claude Desktop's Cowork and Code modes because these modes require protocolVersion: "2025-11-25", but rmcp 1.4.0 only supports up to "2025-06-18".
The MCP handshake completes successfully — the client proceeds through initialize → notifications/initialized → tools/list — and all 22 tools work in standard Claude Desktop chat and Claude Code CLI. But Cowork and Code-in-Desktop apply a stricter version filter and silently exclude servers negotiating older protocol versions.
Evidence
I maintain engraph, a Rust MCP server built on rmcp. A user reported this in devwhodevs/engraph#20 with full MCP logs showing:
Is there a rough timeline for when rmcp will declare 2025-11-25 protocol support? This is currently the only thing blocking Rust-based MCP servers from working in Claude Desktop's newer modes.
Not asking for a commitment — just trying to understand if it's weeks away or months, so downstream projects can plan accordingly.
Thanks for bringing this up, @devwhodevs! I don't think those SEPs are blocking us from supporting 2025-11-25 since they're all optional extensions or future proposals. I've created PR #802 to add support for the protocol version.
@alexhancock@jamadeo Would it be okay if I remove the remaining open SEPs from the implementation project board? I don't see the same SEPs for the other SDKs, and I'm not sure how they were added in the first place.
Activity
DaleSeo commentedon Apr 10, 2026
Thanks for bringing this up, @devwhodevs! I don't think those SEPs are blocking us from supporting
2025-11-25since they're all optional extensions or future proposals. I've created PR #802 to add support for the protocol version.@alexhancock @jamadeo Would it be okay if I remove the remaining open SEPs from the implementation project board? I don't see the same SEPs for the other SDKs, and I'm not sure how they were added in the first place.