Hermes Plant MCP Server

Runnable MCP server and integration examples for Hermes Plant, the Agent Commerce Assurance layer that lets AI agents preflight, approve, and prove consequential actions. Start with a one-cent action-safety check, route only high-risk actions into signed review evidence, and pay per call over x402.

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.

Install the Action Safety skill

Install the public, fail-closed Action Safety skill for Codex, Claude Code, Cursor, and other Agent Skills-compatible clients:

npx skills@1.5.18 add JesseGdotIO/hermesplant-mcp-server --skill protect-agent-action

The skill calls the one-cent quick gate before an exact consequential action, binds the result to that unchanged action, and escalates high or critical risk only when the additional $0.25 is authorized. Review triage is never treated as human approval and the skill never expands the caller's permissions.

Source: skills/protect-agent-action · Install guide and trust boundary

Use the hosted MCP connector

For the complete production tool surface, use the canonical Hermes Plant — Agent Commerce Assurance connector on Glama. It exposes Action Safety, Spend Assurance, signed evidence, payment-policy checks, and the component x402 tools through the live Streamable HTTP endpoint.

This repository is the portable, no-secret discovery bridge. It lets registry crawlers and local clients inspect the live catalog and payment contracts without signing a wallet message or spending funds. The hosted connector is the buyer-facing path for invoking the production tools.

Glama registry

This repo is arranged for Glama to build and inspect the MCP server without secrets or funded wallets:

• glama.json declares the GitHub maintainer.
• The root Dockerfile starts the stdio MCP server in mcp-server/.
• npm run smoke:mcp lists all local MCP tools and fetches the live x402 manifest.
• GitHub Actions validates the MCP server, Docker image, shell examples, and no-spend TypeScript/Python client contracts with their real dependencies.

A Glama release is still an account-side action, not a GitHub release. After claiming the server in Glama, use the Dockerfile admin page to deploy the build, wait for the build test to pass, then publish a Glama release version. That release unlocks Glama's Server Coherence and Tool Definition Quality scoring.

Complementary MCP servers

Hermes Plant governs consequential actions and payments; these independent servers cover adjacent layers of an agent stack:

• SINT Protocol — capability authorization and policy enforcement before execution.
• AgentPay MCP — non-custodial wallet execution with spend limits and approval queues.
• Agent Security Scanner MCP — repository, package, prompt, and skill security scanning.

These links describe functional complementarity, not partnerships or endorsements.

Start with an assurance workflow

Use the free API key for up to 250 calls/month, the $29/month Agent API Pass for regular volume, or per-call USDC on Base. Public proof and machine-readable contracts are available at hermesplant.com/proof and hermesplant.com/openapi.json.

Component catalog

Nineteen hosted x402 endpoints remain available as composable utilities:

Agents discover endpoints through OpenAPI, llms.txt, the x402 manifest, the API catalog, MCP metadata, or agent skills. The workflow links above carry source-specific attribution so registry traffic can be evaluated against paid calls instead of impressions.

How an x402 call works

Client                    Hermes Plant                 Facilitator
  |                            |                            |
  | POST /endpoint             |                            |
  |--------------------------->|                            |
  | 402 Payment Required       |                            |
  | + PAYMENT-REQUIRED         |                            |
  |<---------------------------|                            |
  | sign payment locally       |                            |
  | POST /endpoint             |                            |
  | + PAYMENT-SIGNATURE        |                            |
  |--------------------------->| verify signature           |
  |                            |--------------------------->|
  |                            | ok                         |
  |                            |<---------------------------|
  | 200 OK + result            | settle payment             |
  |<---------------------------|--------------------------->|

1. Client makes an HTTP request.
2. Server replies with 402 Payment Required plus a PAYMENT-REQUIRED header carrying the price, network, asset, recipient, and timeout.
3. Client parses the challenge, signs a USDC transfer authorization locally, and replays the request with a PAYMENT-SIGNATURE header.
4. Server verifies the signature via the facilitator, runs the work, settles the payment on-chain, and returns 200 OK with the result plus 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: