'everything' server notification/progress does not seem to work correctly #2621

When using the 'everything' server, testing the longRunningOperation should send progress notifications, I can see them in the EventStream in the Chrome network tab, but he MCP Inspector doesn't react to them, the tool ends with the final response.

I've been trying to implement progress notifications in an MCP server, but I can't get it to work, the intention was to get Claude to react to progress notifications, but I don't even think Claude implements progress notifications because it doesn't send a progressToken. After digging into it and finding the everything server which implements progress, I cannot see what the intention of this functionality is. Having it only available from custom MCP servers to custom MCP clients doesn't seem all that useful, but I also realise all of this is in the very early stages.

To Reproduce
Steps to reproduce the behavior:

1. Start everything server npx @modelcontextprotocol/server-everything streamableHttp
2. Start MCP Inspector npx @modelcontextprotocol/inspector
3. Connect inspector to http://localhost:3001/mcp
4. Start the longRunningOperation tool

Expected behavior
I would at least expect the MCP inspector to show that the progress notifications are working. There is a window in the inspector for Server Notifications which doesn't show anything, I would expect them to appear here.

Logs
n/a