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90
MCP live MCP 2025-11-25 streamable-http

ONCE — Exactly-Once Reliability for AI Agent Actions

io.github.gsterlingpress/once

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

Watch this dependency Share evidence report
Uptime
100.0%
5 direct probes · 30d
Response
764ms
last probe
Tools
2
callable
Resources
0
readable
Prompts
0
available
Primary URL
https://optimistic-compassion-production.up.railway.app/mcp
Score: 90/100
Handshake verified by our own probe.
pass Answers the MCP handshake 50/50
The handshake and the list calls succeeded on the primary URL.
pass Lists tools, resources or prompts 30/30
2 tools, 0 resources, 0 prompts returned.
partial 3 or more catalogue items 0/10
2 items in total; 3 or more earns these points.
How to earn +10 points
Expose at least three tools, resources or prompts
Split a catch-all tool into focused ones, or publish your docs and templates as resources and prompts.
Docs →
pass Describes itself 10/10
93 characters; more than 30 earns these points.

Tools · 2

once_demo

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 effect is required.

once_execute

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, modify, submit, or de…

How to use

Claude Desktop or claude.ai: add a custom connector (Customize → Connectors; on Team and Enterprise plans an owner adds it under Organization settings → Connectors) with this server URL: https://optimistic-compassion-production.up.railway.app/mcp

Cursor or Cline: add to your MCP config:

{
  "mcpServers": {
    "once_\u2014_exactly-once_reliability_for_ai_agent_actions": {
      "url": "https://optimistic-compassion-production.up.railway.app/mcp",
      "transport": "streamable-http"
    }
  }
}