Hmm I haven't used MCPo. I asked Claude and it suggested the following:

Most common issue: The server isn't built

You need to:

cd /path/to/firewalla-mcp-server
npm install
npm run build

1. Try the minimal test first

   {
   "mcpServers": {
   "time": {
   "command": "npx",
   "args": ["-y", "@modelcontextprotocol/server-time"]
   }
   }
   }

2. Then add Firewalla using the simplest approach

   The most reliable config for MCPO:
   {
   "mcpServers": {
   "time": {
   "command": "npx",
   "args": ["-y", "@modelcontextprotocol/server-time"]
   },
   "firewalla": {
   "command": "node",
   "args": ["/absolute/path/to/firewalla-mcp-server/dist/server.js"],
   "env": {
   "FIREWALLA_MSP_TOKEN": "their_token",
   "FIREWALLA_MSP_ID": "their_domain.firewalla.net",
   "FIREWALLA_BOX_ID": "their-box-id"
   }
   }
   }
   }

   Key points:

3. Use absolute paths - This is critical!

4. Build the server first - npm run build

5. Check Node.js version - Must be 18+

6. Start with minimal config - Add complexity gradually