Hello Dlubal Team,
I am using RFEM 6.14 (version 6.14.0005) with the student license and would like to use the RFEM MCP Server for AI-supported evaluation of FE stress results. After extensive tests with two different MCP clients, I have encountered two separate, reproducible compatibility issues which I describe below.
The first issue concerns the Cline extension in Visual Studio Code. When Cline calls a tool of the RFEM MCP Server, it automatically sends an additional parameter named task_progress internally, which is intended for Cline's own progress display. However, the RFEM MCP Server rejects this unknown parameter with the following error: "1 validation error for call[start_RFEM] task_progress – Unexpected keyword argument". This behavior is documented as a known bug in Cline (GitHub Issues #10426, #9684, and #8256 in the cline/cline repository) and affects several different MCP servers. A possible solution would be to adapt the RFEM MCP Server to ignore unknown additional parameters such as task_progress instead of rejecting the entire request. This would significantly improve compatibility with Cline and potentially other MCP clients with similar behavior.
The second issue concerns the Claude Code CLI from Anthropic. When using the SSE transport (endpoint /sse), the connection is reported as successful, but every tool call fails with the error "MCP error -32602: Invalid request parameters," even though the affected tools like health_check and start_RFEM do not expect any parameters. When using the Streamable HTTP transport (endpoint /mcp), Claude Code sends its requests to the path /messages/?session_id=..., resulting in a 404 error since this path is not served by the RFEM MCP Server. Both transport protocols are therefore incompatible with the current RFEM MCP Server.
In summary, both tested MCP clients – Cline and Claude Code CLI – are currently unable to reliably use the RFEM MCP Server. Since these are compatibility issues at the protocol level that cannot be resolved by configuration changes on my side, I would appreciate an assessment of whether and when a server-side adjustment is planned.
For completeness, my setup: RFEM 6.14.0005, student license, Windows 11, Cline (current version), Claude Code CLI 2.1.197, MCP Server version 2.14.0.
Thank you very much for your support!
Best regards,
Ruben