Allowance Engine

MCP server

https://www.allowanceengine.com/sdk/mcp.mjs is a stdio MCP server. It loads agent.mjs from the same folder and exposes the agent's arm as three tools.

mkdir arm-mcp && cd arm-mcp && npm init -y && npm i @solana/web3.js
curl -O https://www.allowanceengine.com/sdk/agent.mjs -O https://www.allowanceengine.com/sdk/mcp.mjs

Claude Code:

claude mcp add arm -e OWNER=<wallet> -e ARM=0 -e AGENT_KEY=<secret> \
  -e FACILITATOR=https://www.allowanceengine.com/api/x402 -- node $(pwd)/mcp.mjs

Claude Desktop or any MCP client:

{
  "mcpServers": {
    "arm": {
      "command": "node",
      "args": ["/absolute/path/arm-mcp/mcp.mjs"],
      "env": { "OWNER": "<wallet>", "ARM": "0", "AGENT_KEY": "<secret>", "FACILITATOR": "https://www.allowanceengine.com/api/x402", "MAX_PER_CALL": "0.5" }
    }
  }
}

Tool	Input	Does
`arm_status`	none	Balance, budget left, daily cap, spent today, calls, allow-list.
`paid_fetch`	`url`, `method`, `body`	Fetches a URL and pays its 402 from the arm.
`pay`	`to`, `amount_usdc`	Gasless USDC payment to an allow-listed address.