Hermes Plant MCP Server

Runnable MCP server and integration examples for Hermes Plant: deterministic finance and quant APIs that AI agents call and pay for per call over x402. No API keys, no shared secrets, no hallucinated math.

What's here: a runnable stdio MCP bridge for registry crawlers and local clients, plus drop-in examples in curl, TypeScript, Python, CrewAI, LangChain, and MCP client configs for Claude Desktop / Cline / Cursor.

What is Hermes Plant?

A hosted catalog of deterministic finance + quant endpoints AI agents call and pay for per call:

Agents discover endpoints through OpenAPI, llms.txt, the x402 manifest, the API catalog, MCP metadata, or agent skills. Pricing is metered per call in USDC on Base mainnet.

Related MCP server: @1ly/mcp-server

How an x402 call works

┌────────┐                          ┌───────────────┐                ┌──────────────┐
│ Client │ ── POST /endpoint ─────▶ │ Hermes Plant  │                │  Facilitator │
│        │                          │               │                │ (Coinbase)   │
│        │ ◀── 402 + challenge ─── │               │                │              │
│        │                          │               │                │              │
│        │ ── POST + signature ──▶ │               │ ─ verify ────▶ │              │
│        │                          │               │ ◀─ ok ─────── │              │
│        │ ◀── 200 + result ────── │               │ ─ settle ───▶  │              │
└────────┘                          └───────────────┘                └──────────────┘

1. Client makes an HTTP request.

2. Server replies with 402 Payment Required + a PAYMENT-REQUIRED header carrying the price, network, asset, recipient, and a server-issued nonce.

3. Client parses the challenge, signs a USDC transfer authorization locally, replays the request with a PAYMENT-SIGNATURE header.

4. Server verifies the signature via the facilitator, runs the work, settles the payment on-chain, returns 200 OK with the result and a PAYMENT-RESPONSE header.

The full spec lives at github.com/x402-foundation/x402.

Discovery surfaces

These let any agent (or human) self-onboard without help:

• hermesplant.com/llms.txt — agent-readable catalog

• hermesplant.com/openapi.json — full OpenAPI 3.1

• hermesplant.com/.well-known/x402 — x402 manifest (facilitator, network, payTo)

• hermesplant.com/.well-known/api-catalog — RFC 9727 API catalog

• hermesplant.com/.well-known/mcp/server-card.json — MCP server descriptor

• hermesplant.com/mcp — Streamable-HTTP MCP endpoint

Quickstart

Pick the runtime that matches your stack:

MCP server registry build

This repo includes a root glama.json and root Dockerfile for MCP registry crawlers:

docker build -t hermesplant-mcp-server .
docker run --rm -i hermesplant-mcp-server

The container starts the stdio MCP bridge in mcp-server/, which exposes Hermes Plant discovery tools and hosted MCP metadata without requiring API keys.

Wallet setup

Every example assumes:

• A funded wallet on Base mainnet (chain id 8453).

• A small USDC balance for paying per-call fees (typical call: $0.01–$0.50).

• An EOA private key (any standard EVM wallet — MetaMask, Coinbase Smart Wallet, Privy, Dynamic, etc.) — examples read it from WALLET_PRIVATE_KEY.

For testing without real funds, point your client at Base Sepolia (84532) and use the testnet x402 facilitator at https://x402.org/facilitator. Hermes Plant supports both — its /.well-known/x402 manifest declares the active network.

Status

These examples target the production deployment at hermesplant.com. Endpoint signatures may evolve — always cross-reference openapi.json and the /.well-known/x402 manifest before going to production.

Contributing

Issues and PRs welcome. New runtime? New framework? Open a PR with one working example and a tight README.

License

MIT — see LICENSE.