I am working on develop my own MCP server and trying to invoke some tools using the Responses API. I am using FastMCP python package for the server which supports SSE and Streamable HTTP transport protocols. My server is deployed locally and i’ve been using ngrok so the OpenAI client will be able …

OpenAI MCP client starts to fail when moving from SSE to Streamable HTTP

vosdale July 1, 2025, 1:51am 7

How I fixed it: Add stateless_http=True to your FastMCP initialization:

mcp = FastMCP("bloomy-mcp", stateless_http=True)

9 Likes

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