feat: Progress Support for Long Running Tool Calls ⏳

[pulkitsharma07]

Progress Support for Long Running Tool Calls

progress_flow.mov

The MCP Inspector now fully supports the Model Context Protocol Progress Flow specification, which enables:

• Optional progress tracking for long-running operations
• Added new configuration settings to the MCP Inspector for supporting this:
  • MCP_REQUEST_TIMEOUT_RESET_ON_PROGRESS: Controls whether timeouts reset on progress notifications. Default: true
  • MCP_REQUEST_MAX_TOTAL_TIMEOUT: Sets maximum total timeout for requests with progress notifications. Default: 60000 ms

Other Changes

1. Run tool button now shows as a spinner while the tool is running (and becomes disabled).
2. Improves error handling for callTool exceptions.
3. Some minor code-refactoring, to improve readability.
4. Progress notifications are now handled little differently than other notifications, check .onprogress hook in useConnection

Testing

• Used the everything MCP Server's longRunningOperation tool.
• To enable progress notifications set MCP_REQUEST_TIMEOUT_RESET_ON_PROGRESS to true (default).
  • if tool response duration is less than MCP_REQUEST_MAX_TOTAL_TIMEOUT then tool call will succeed.
  • otherwise, it will fail with MCP error -32001: Maximum total timeout exceeded
    
• Increased MCP_REQUEST_MAX_TOTAL_TIMEOUT to 200000 (200 seconds) and verified if duration is set to 150 seconds, the tool execution completes fine.

• Disabled MCP_REQUEST_TIMEOUT_RESET_ON_PROGRESS and verified that tool correctly times out.

Related Issues

• Fixes Usability issue for long-running tasks #223

[pulkitsharma07]

Hi, @cliffhall, pinging this for review (apologies if already checking)

[cliffhall]

Tested locally and this works great. Verified max timeout works. Only one beef with the makeRequest renaming.

[cliffhall]

One more suggestion here.

These configuration variable names are really not looking good, particularly with wrapping.

Could we show just words like:

• Request Timeout
• Reset Timeout on Progress
• Max Timeout with Progress
• Proxy Full Address

The env var to use could be in the tooltip or just in the README.

[pulkitsharma07]

Fully agree with that. The env var by itself is not descriptive, so I have added a label in configItem, and used that in the UI. The description remains in the tooltip.

[cliffhall]

Much better looking.