ONCE — Exactly-Once Reliability for AI Agent Actions for Cursor

io.github.gsterlingpress/once

Prevent duplicate AI-agent side effects with idempotency, verification, and durable receipts.

client:Cursor transport:streamable-http

Install ONCE — Exactly-Once Reliability for AI Agent Actions in Cursor

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

{
  "mcpServers": {
    "once": {
      "url": "https://optimistic-compassion-production.up.railway.app/mcp"
    }
  }
}

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