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:

Endpoint	Use it for	Hosted path
DealAnalyzer	DCF, IRR, XIRR, NPV	/agent-services/dealanalyzer
Waterfall	LP/GP private-equity distribution waterfalls	/agent-services/waterfall
Options	Black-Scholes pricing + Greeks	/agent-services/options
Bond	Yield, duration, convexity	/agent-services/bond
CashflowLens	Cash-flow projection + sensitivity	/agent-services/cashflowlens
PortfolioGuard	Portfolio risk scoring	/agent-services/portfolioguard
WalletGuard	Wallet AML + sanctions screening	/agent-services/walletguard
EmailGuard	Email reputation + risk	/agent-services/emailguard
DestructGuard	Block destructive AI-agent commands	/agent-services/destructguard
MCP risk	Score MCP server risk before connecting	/agent-services/mcp-risk
Evidence	Evidence-bundle for paid calls	/agent-services/evidence
Payment policy	Inspect/score an x402 payment policy	/agent-services/payment-policy
ReviewQueue	Human-in-the-loop approval routing	/agent-services/reviewqueue

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.

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:

Runtime	Folder	Notes
curl / Bash	curl/	Pure shell; useful for inspecting the 402 handshake
TypeScript	typescript/	Uses x402-fetch + @modelcontextprotocol/sdk
Python	python/	Uses the x402 package
CrewAI	crewai/	Finance-agent crew calling Hermes endpoints
LangChain	langchain/	LangChain Tool wrapping Hermes
MCP config	mcp-config/	One-paste config for Claude Desktop / Cline / Cursor
MCP server	mcp-server/	Runnable stdio MCP bridge for discovery, server-card inspection, and hosted-tool listing

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.