inspector immediately shuts down

[BSVogler]

Hi!

So I installed the MCP Python SDK with uv and basically built a hello world. It works in Claude. But whenever I launch the

npx @modelcontextprotocol/inspector python main.py or mcp inspector main.py it prints Starting MCP inspector...

and then just shuts down. I was expecting that it prints some url, opens the browser or stays open etc. Am I doing something wrong? I read the documentation but it only shows a screenshot and not shows the expected behavior.