Description
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
I tried to create my custom/demo MCP Server using the python-sdk. mcp server got installed in the claude desktop app.
INFO Added server 'FastMCP' to Claude config claude.py:137 INFO Successfully installed FastMCP in Claude app cli.py:486
After the installation, when i tried to open the Claude Desktop app in my mac, i got the below error and application never opened.
`
[07/03/25 09:05:11] INFO Added server 'FastMCP' to Claude config claude.py:137
INFO Successfully installed FastMCP in Claude app cli.py:486
Uncaught Exception:
Error: dialog module can only be used after app is ready
at checkAppInitialized (node:electron/js2c/browser_init:2:22982)
at messageBox (node:electron/js2c/browser_init:2:24872)
at Object.showMessageBox (node:electron/js2c/browser_init:2:21217)
at T8e (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index-BV1dxcNB.js:107:9470)
at Ar (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index-BV1dxcNB.js:107:9969)
at Object. (/Applications/Claude.app/Contents/Resources/app.asar/.vite/build/index-BV1dxcNB.js:261:7978)
at Module._compile (node:internal/modules/cjs/loader:1738:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1904:10)
at Module.load (node:internal/modules/cjs/loader:1472:32)
at Module._load (node:internal/modules/cjs/loader:1289:12)
`
Example Code
#main.py file.
from mcp.server.fastmcp import FastMCP
#create an MCP Server
mcp = FastMCP()
# add an additon tool
@mcp.tool()
def add(a: int, b: int ) -> int:
return a + b
#add dynamic greeting resource
@mcp.resource("greeting://{name}")
def get_greeting(name: str) -> str:
return f"Hello, {name}!"Python & MCP Python SDK
mcp[cli]>=1.10.1