fosterrx-verify-mcp-server

A read-only MCP server that verifies Foster Rx certificates using public material only: the world-readable certificate envelope and the Ed25519 trust anchor published at https://fosterrx.com/.well-known/angis-signing-key-v1.pub.

No credential exists anywhere in this codebase. That is not a deployment choice but the product's argument in server form: verification that required Foster Rx's permission would not be verification. This repository being public and auditable is part of the same argument.

Tools

Tool	What it does
fosterrx_verify_certificate	Real Ed25519 verification of the signed canonical bytes against the live trust anchor. Verdicts: verified / signature_invalid / not_found / tool_fault.
fosterrx_get_certificate_record	The full signed canonical, decoded verbatim. No verification performed; nothing renamed or improved on.
fosterrx_get_trust_anchor	The published public key, plus instructions for verifying with no Foster Rx software at all.

Verdict discipline

• not_found is not invalid. An unpublished certificate is a fact about the public register, never a claim about any artifact.
• tool_fault is not invalid. A network failure or malformed input is a fact about this tool's run and says nothing about the certificate.
• signature_invalid is asserted only after Ed25519 arithmetic failed over the signed bytes under the published key.
• Both issued identifier shapes are accepted (FRXS-<16 hex> and FRXS-<uuid>); a pattern inferred from only one of them has previously rejected every real certificate.

Run

npm ci && npm run build
PORT=8080 node dist/index.js     # MCP endpoint at POST /mcp, health at /healthz

Deploy (Cloud Run)

gcloud run deploy fosterrx-verify-mcp --source . \
  --region us-east4 --project fosterrx-prod --allow-unauthenticated

Public, unauthenticated, by design: it can only read what the world can already read.

Verify with your own AI

This server is public. Anyone can register it and verify any published Foster Rx certificate — no account, no permission:

1. In Claude (or any MCP client): add a custom connector with URL https://fosterrx-verify-mcp-630726936307.us-east4.run.app/mcp
2. Ask: verify FRXS-5330F9E368BA4536
3. The reader gets the cryptographic verdict — not the issuer's word.