mcp dev main.py的时候报错

Question

mcp dev main.py 执行的时候会去打开浏览器 如何禁止默认打开浏览器，因为在打开浏览器的时候会报错 错误如下:
Starting MCP inspector…
⚙️ Proxy server listening on localhost:6277
🔑 Session token: 114cb74b9e94e9eacecf084180f92097a9428af67c8eafd461cb95e5e215fd2e
Use this token to authenticate requests or set DANGEROUSLY_OMIT_AUTH=true to disable auth

🚀 MCP Inspector is up and running at:
http://localhost:6274/?MCP_PROXY_AUTH_TOKEN=114cb74b9e94e9eacecf084180f92097a9428af67c8eafd461cb95e5e215fd2e

!!! 在打开浏览器的时候出现错误 如何禁止下面的行为
🌐 Opening browser…
node:internal/child_process:420
throw new ErrnoException(err, ‘spawn’);
^

Error: spawn UNKNOWN
at ChildProcess.spawn (node:internal/child_process:420:11)
at Object.spawn (node:child_process:754:9)
at baseOpen (file:///C:/Users/yuanlidi/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/open/index.js:244:34)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5) {
errno: -4094,
code: ‘UNKNOWN’,
syscall: ‘spawn’
}

Node.js v22.17.0
Error:
🚀 MCP Inspector is up and running at:
http://localhost:6274/?MCP_PROXY_AUTH_TOKEN=114cb74b9e94e9eacecf084180f92097a9428af67c8eafd461cb95e5e215fd2e

🌐 Opening browser…
node:internal/child_process:420
throw new ErrnoException(err, ‘spawn’);
^

Error: spawn UNKNOWN
at ChildProcess.spawn (node:internal/child_process:420:11)
at Object.spawn (node:child_process:754:9)
at baseOpen (file:///C:/Users/yuanlidi/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/open/index.js:244:34)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5) {
errno: -4094,
code: ‘UNKNOWN’,
syscall: ‘spawn’
}

Answer 1

暮闲 2025-07-30 21:35:14

hello 同学你好，这个问题很好。通过 mcp dev main.py能调试，但是只能调试基于FastMCP初始化的MCP Server。
但是通常推荐并且我们课程的演示，都是自定义list_tools的方式启动MCP Server，这样能方便把每个mcp tool描述的更加清楚。
所以这里就有疑问，自定义的list_tools MCP Server也要用mcp的调试工具怎么办？

详细的步骤比较长，我整理为电子书了，对应为《5-12 自定义使用MCP官方调试工具》。