context.report_progress not sending notifications on streamable-http

[abdhx]

Initial Checks

• I confirm that I'm using the latest version of MCP Python SDK
• I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue

Description

Hello 👋

It seems like context.report_progress is not sending any notifications on streamable-http.
I checked and the reason is that related_request_id is not specified in the underlying function.

A fix that work on my side in the file src/mcp/server/fastmcp/server.py:

async def report_progress(self, progress: float, total: float | None = None, message: str | None = None) -> None:

# <---- non important code is skipped here --->

await self.request_context.session.send_progress_notification(
    progress_token=progress_token,
    progress=progress,
    total=total,
    message=message,

    # ADD this line to fix the issue
    related_request_id=self.request_id,
)

I created a PR to add that line.

Example Code

from mcp.server.fastmcp import Context, FastMCP

mcp = FastMCP("StatelessServer", stateless_http=True)

@mcp.tool()
async def example(ctx: Context) -> str:
    await ctx.report_progress(0, None, "This does not work")
    await ctx.session.send_progress_notification(
        ctx.request_context.meta.progressToken, 0, None, "But this works perfectly", ctx.request_id
    )
    return "Done"

mcp.run(transport="streamable-http")

Python & MCP Python SDK

mcp 1.9.4
Python 3.13.3
uv 0.7.13

[catbbblack]

yes,v1.10.1 has the same question.

[lukebuehler]

can also confirm progress notifications still don't work on 1.10.1 with streamable http

[catbbblack]

i try send post request directy to server without using clientAPI, i get the return progress. you can try it later @lukebuehler
such as {"jsonrpc": "2.0", "method": "tools/call", "params": {"name": "xxx", "argument": {}, "_meta":{"progress_token": "0"}}, "request_id": "0"}
note that: if you use the newest sdk, you need to modify the source code