ONCE — Exactly-Once Reliability for AI Agent Actions for VS Code

io.github.gsterlingpress/once

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

client:VS Code transport:streamable-http

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

.vscode/mcp.json

{
  "servers": {
    "once": {
      "type": "http",
      "url": "https://optimistic-compassion-production.up.railway.app/mcp"
    }
  }
}

Requires agent mode. MCP: Open User Configuration puts the same block in every workspace. VS Code docs