Config path:

~/.elcro/mcp.json

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["-y", "@playwright/mcp@latest"]
    },
    "remote-example": {
      "url": "https://mcp.example.com/sse"
    }
  }
}

JSONC (comments) is accepted. Edit via Settings → Tools & MCPs or open the file from that panel.