Eicitation Context request timeout via streamable-http transport "MCP error -32001: Request timed out"

[longcld]

Question

I got "MCP error -32001: Request timed out" when using elicitation context method via "streamable-http" transport. But it's work successfully with sse or stdio transport.

The workflow are:

1. Calling the elicitation tool from client
2. Server already receive the request calling tool and return the elicitation format
3. On client, fill information and send back to the server.
   --> The server not receive the input information then return "MCP error -32001: Request timed out"

Additional Context

mcp==1.16.0
python=3.13

[maxisbey]

Please supply a minimal reproducible example code snippet that we can run to reproduce the issue. Would make it easier for us to look into it :)

[longcld]

#server.py

from mcp.server.fastmcp import Context, FastMCP
from mcp.server.session import ServerSession

from pydantic import Field, BaseModel

import asyncio
# from type_catalog.server import mcp as type_catalog_mcp

mcp = FastMCP("test", stateless_http=True, port=4001)


class UserInfo(BaseModel):
    name: str = Field(..., description="The user's name")
    age: int = Field(..., description="The user's age")

@mcp.tool()
async def pattern_example(ctx: Context) -> str:
    result = await ctx.elicit(
        message="Please provide your name",
        schema=UserInfo
    )

    if result.action == "accept" and result.data:
        return f"Hi {result.data.name}"
    elif result.action == "decline":
        return "No name provided"
    else:  # cancel
        return "Operation cancelled or no name provided"

if __name__ == "__main__":
    mcp.run(transport="streamable-http")

• Then i start the server with python3 server.py and a MCP Inspector Client to interact mcp dev server.py.
• On the MCP Inspector Client UI, i connected to the server via "http://0.0.0.0:4001/mcp" and call the "pattern_example" tool. I fill the user name and age then press Submit. And finally it return "MCP error -32001: Request timed out" after about 10 seconds.

Thanks for your help.

[longcld]

I did the same for the SSE protocol and it worked perfectly; only the streamable-http protocol throws a timeout exception.