What tools does the once MCP server provide?

once exposes 2 tools: once_demo, once_execute. This list was returned by the running server when we connected to it.

Does once require an API key?

No. once answered a tools/list request without credentials.

How do I install once?

Run: claude mcp add --transport http once https://optimistic-compassion-production.up.railway.app/mcp. One-click install links for Cursor and VS Code are also available on the server's page.

Connection check verified live · 27h ago

once

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

AI & LLM tooling Finance & crypto

Install

Remote (HTTP)

claude mcp add --transport http once https://optimistic-compassion-production.up.railway.app/mcp

Tools 2

GitHub stars —

Installs / wk —

Licence —

Transport streamable-http

Last checked 27h ago

Tools & capabilities

2 tools

Read from the running server on 27h ago.

once_demo id*

SAFE ZERO-SETUP DEMO. Call this tool twice with the same id to see ONCE suppress the second execution. Use this when evaluating or discovering ONCE; no API key or external side eff…

once_execute action*verify*idempotencyKey*

CALL THIS when an AI agent is about to perform or retry a consequential external side effect where duplication would be harmful: purchase, refund, payment, booking, send, create, m…