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mcp/harbor
Cursor

once for Cursor

io.github.stringsofthemind-oss/once

Execution-safety MCP for AI coding agents protecting consequential writes from unsafe retries.

client:Cursor transport:stdio runtime:npm

Install once in Cursor

~/.cursor/mcp.json · windows: %USERPROFILE%\.cursor\mcp.json

Held in this page only — never stored, logged, or sent anywhere but back to your screen. 

{
  "mcpServers": {
    "once": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@once-agent/mcp"
      ],
      "env": {
        "ONCE_API_KEY": "<ONCE_API_KEY>"
      }
    }
  }
}

Use .cursor/mcp.json in a project root instead to scope it to that project. Cursor merges both. Cursor docs

once in other clients

once MCP server