#906 - Add watchPaths option to McpHub for file change detection

[01Rian]

Context

#906

The core issues are:

1. Hardcoded path detection (build/index.js) prevents watching files in alternate directories
2. File watchers overwrite each other due to reusing the same Map key
3. No support for flexible path configurations beyond the hardcoded pattern
4. Inability to watch multiple files or directories without custom configuration

Implementation

1. Added support for multiple file watchers per server in the McpHub class

   • Changed the fileWatchers map to store arrays of watchers instead of a single watcher
   • Updated the setupFileWatcher method to maintain multiple watchers per server
   • Modified the removeAllFileWatchers method to handle arrays of watchers

2. Fixed issue where custom watchPaths watchers would overwrite the fallback build/index.js watcher

   • Previous implementation used the server name as a key, causing one watcher to replace the other
   • Now multiple watchers can coexist for the same server, each monitoring different paths

3. Added proper error handling to file watcher callbacks

   • Made change event callbacks async functions
   • Added try/catch blocks around await this.restartConnection(name) calls
   • Included detailed error logging that identifies which watcher and path triggered the error

4. Improved logging to distinguish between different types of watchers

   • Added clear console messages to indicate which watcher detected a change
   • Included the changed file path in error messages for easier debugging

Screenshots

before	after

How to Test

Configure an MCP server with explicit watchPaths:

{
  "mcpServers": {
    "my-server": {
      "type": "stdio",
      "command": "node",
      "args": ["./dist/index.js"],
      "watchPaths": ["./dist/**/*.js"]
    }
  }
}

Get in Touch

---

Important

Adds watchPaths option to McpHub for custom file change detection and server restart.

• Behavior:
  • Adds watchPaths option to BaseConfigSchema in McpHub.ts for custom file path watching.
  • Implements file watchers in setupFileWatcher() to restart servers on file changes.
• Configuration:
  • Updates BaseConfigSchema to include watchPaths as an optional array of strings.
• Testing:
  • Example configuration provided for testing with watchPaths in MCP server setup.

^{This description was created by for c5202d4. It will automatically update as commits are pushed.}

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[mrubens]

Thank you for the contribution!

[hannesrudolph]

@01Rian Do you happen to have discord? would love to include you in our contributors private channel. My username is hrudolph if you can please reach out to me.

[01Rian]

@hannesrudolph Yes, I sent you a private message on discord.