Obol MCP

The MCP server that lets any AI agent discover, pay for, and call APIs per request in USDC — gasless, sub-cent, no accounts, no API keys. Built on x402 + Circle Gateway.

obol-arc.web.app · Docs · Marketplace

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What is Obol?

Obol is the marketplace where AI agents buy from agents. Providers list any HTTP API with a per-call price; agents discover those services and pay automatically per request in USDC.

• Monetize any API — list an endpoint, set a price, get paid per call. You keep 100% (0% commission).
• Gasless nanopayments — agents sign off-chain EIP-3009 authorizations (zero gas); Circle Gateway batch-settles. Payments from $0.000001.
• No accounts, no API keys — the agent's wallet is its identity.
• One integration unlocks the whole directory.

This package is the MCP server — add it to Claude, Cursor, or any MCP-compatible agent and it can find services, pay, and call them automatically.

Install

npx -y @superbigroach/obol-mcp

Configure (MCP client)

Add to your MCP config (e.g. Claude Desktop claude_desktop_config.json, Cursor, etc.):

{
  "mcpServers": {
    "obol": {
      "command": "npx",
      "args": ["-y", "@superbigroach/obol-mcp"],
      "env": {
        "OBOL_API_KEY": "obl_sk_live_<your-key>",
        "OBOL_AGENT_KEY": "0x<agent-wallet-private-key>"
      }
    }
  }
}

• OBOL_API_KEY — get one at obol-arc.web.app/settings. Required for listing + metered calls.
• OBOL_AGENT_KEY — the agent wallet's private key, used to sign gasless payment authorizations. Only needed for paying (pay_and_call); discovery and listing work without it. Fund the wallet with testnet USDC at faucet.circle.com.

Never commit your keys. Use environment variables.

Tools

Tool	What it does
find_service	Search the directory for an API by capability/category.
pay_and_call	Pay the per-call price and invoke the endpoint — gas-free.
get_balance	Check your USDC balance.
deposit	Fund your Gateway balance once for gasless spending.
list_service	Publish your own API to the marketplace and earn per call.

Example

You: "Find a weather API and get the forecast for New York."

Agent (via Obol MCP):
  → find_service("weather")
  → pay_and_call(weatherUrl, { lat: 40.71, lon: -74.01 })   # pays $0.001 USDC, gasless
  → "It's 29°C with 13 km/h winds in New York."

See examples/ for runnable snippets.

How payments work

1. An unpaid request returns HTTP 402 Payment Required with a price.
2. The agent signs an off-chain EIP-3009 authorization (zero gas) and retries.
3. The result is served immediately; Circle Gateway batch-settles on-chain.

Per-call gas is $0 because settlement is batched — that's what makes sub-cent payments viable. Read more →

Pricing

• Listing is free. Obol takes 0% commission per call — sellers keep 100%.
• Optional Featured / Scale subscriptions add directory visibility (never a cut of your transactions).

Links

• Website: https://obol-arc.web.app
• Docs: https://obol-arc.web.app/docs
• npm: https://www.npmjs.com/package/@superbigroach/obol-mcp
• MCP: https://modelcontextprotocol.io
• x402: https://x402.org · EIP-3009: https://eips.ethereum.org/EIPS/eip-3009

License

MIT © Obol