[Bug] MCP tool works and responds, but Claude Desktop pop-up shows "Could not attach to MCP server" #576
jigarvyasidea
started this conversation in
General
[Bug] MCP tool works and responds, but Claude Desktop pop-up shows "Could not attach to MCP server"
#576
Replies: 0 comments
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Uh oh!
There was an error while loading. Please reload this page.
-
Pre-submission Checklist
Discussion Topic
Everything is working properly:
MCP server is running
Configuration is valid
The tool works and gives correct responses when tested directly
The MCP tool itself is functioning fine.
But in Claude Desktop pop-up, it still shows:
So the tool is usable, but the Desktop client UI wrongly shows this error.
Steps to Reproduce
Start MCP server (works fine independently).
Add configuration in claude_desktop_config.json.
Restart Claude Desktop.
Test the tool → it responds correctly.
Open Desktop pop-up → error message appears:
Expected Behavior
Claude Desktop should:
Attach to the MCP server without error
Actual Behavior
MCP tool works and returns responses
But the Claude Desktop pop-up shows only an error message:
Additional Notes
Everything else works perfectly, only the pop-up shows a misleading error
Tool calls and responses are successful despite the error
Tried restart, absolute paths, different transports → still same result
Beta Was this translation helpful? Give feedback.
All reactions