client.set_roots not update the roots

[xxzero12]

Hi, is trying to test the root capability, somewhat the client set the root but the server still return old one

Ex:

Client.py

client = Client(
    "http://localhost:9000/sse", 
    sampling_handler=sampling_handler, 
    log_handler=log_handler,
    roots=[
        "file://home/projects/roots-example/frontend"
    ],
    message_handler=message_handler)

async def main():
    # Connection is established here
    async with client:
        await client.call_tool("get_forecast",{ "latitude": 47.6101, "longitude": -122.2015 })
        client.set_roots([
            "file://home/projects/roots-example/backend"
        ])
        await client.send_roots_list_changed()
        await client.call_tool("get_forecast",{ "latitude": 47.6101, "longitude": -122.2015 })

if __name__ == "__main__":
        asyncio.run(main())

Server.py

logging.basicConfig(level=logging.DEBUG)
mcp = FastMCP(name="Tutorial Server")


@mcp.tool()
async def get_forecast(latitude: float, longitude: float, ctx: Context) -> str:
    """Get weather forecast for a location.

    Args:
        latitude: Latitude of the location
        longitude: Longitude of the location
    """
    roots = await ctx.list_roots()
    await ctx.info(f"{roots}")
    await ctx.info(f"Info Message: Processing coordinates: {latitude}, {longitude}")

if __name__ == "__main__":
    mcp.run(transport="sse", host="127.0.0.1", port=9000)

Somewhat the result is like below

First call
DEBUG:mcp.server.sse:Sending message via SSE: root=JSONRPCRequest(method='roots/list', params=None, jsonrpc='2.0', id=1)
DEBUG:mcp.server.sse:Received JSON: b'{"jsonrpc":"2.0","id":0,"result":{"roots":[{"uri":"file://home/projects/roots-example/frontend"}]}}'
Second call(should return backend since set the root)
DEBUG:mcp.server.sse:Received JSON: b'{"method":"notifications/roots/list_changed","jsonrpc":"2.0"}'
DEBUG:mcp.server.sse:Sending message via SSE: root=JSONRPCRequest(method='roots/list', params=None, jsonrpc='2.0', id=1)
DEBUG:mcp.server.sse:Received JSON: b'{"jsonrpc":"2.0","id":1,"result":{"roots":[{"uri":"file://home/projects/roots-example/frontend"}]}}'

[felixweinberger]

Hi @xxzero12 thanks for this report - is this still a problem? Asking as it's been a while since this report.