openfang-rail
Deterministic business-identity validation (IBAN, LEI, VAT, UK company number) and rental due-diligence checks, paid per call via x402 — gasless EIP-3009 USDC on Base. Non-custodial, no accounts, no API keys: agents pay directly from their wallets, and every result carries a signed, offline-verifiable XDR-1 receipt.
Live endpoint: https://rail.akrivis.in · 28 tools · first N calls/day free, then from $0.000999/call (dynamic — idle prices decay toward the floor, demand bumps them; live quotes at /health).
Endpoints
| Path | What it is |
|---|---|
POST /mcp |
MCP server (JSON-RPC 2.0: initialize, tools/list, tools/call) |
POST /v1/tools/{tool}/call |
REST entry point, body {"input": { ... }} |
GET /.well-known/x402.json |
x402 discovery (resources, prices, example inputs) |
GET /.well-known/mcp.json |
MCP discovery (tool schemas, receipt signer) |
GET /.well-known/agent.json |
A2A agent card |
GET /health |
live quotes + tool count |
GET /playground |
browser form: try any tool on the free tier |
GET /leaderboard, GET /profile/{address} |
buyer stats (on-chain identity only — no signups) |
Quickstart (HTTP)
# free tier — no payment needed
curl -s https://rail.akrivis.in/v1/tools/iban-check/call \
-H 'content-type: application/json' \
-d '{"input":{"iban":"GB82WEST12345698765432"}}'
When the free tier is exhausted the API answers 402 with a payment challenge (EIP-3009 TransferWithAuthorization for USDC on Base). Sign the voucher with your wallet, retry with the payment header, and the response includes the settlement result plus a signed receipt. Any x402 client library handles this dance; the canonical flow is documented at the x402 protocol.
Quickstart (stdio / Docker)
The rail is a hosted HTTP MCP endpoint. mcp-bridge.mjs is a zero-dependency stdio↔HTTP bridge for hosts that only speak MCP over stdio (Glama, Docker MCP Toolkit, desktop client configs):
docker build -t openfang-rail .
docker run -i --rm openfang-rail
{
"mcpServers": {
"openfang-rail": {
"command": "docker",
"args": ["run", "-i", "--rm", "openfang-rail"]
}
}
}
The container holds no secrets and no local state — it proxies protocol traffic to the hosted endpoint, whose free tier applies. Point it elsewhere with MCP_ENDPOINT.
Receipts
Every tool result carries an XDR-1 receipt: a canonical, keccak-hashed field set signed by the rail's key (published in /.well-known/mcp.json). Anyone can verify a receipt offline — no trust in the server needed after the fact. See worker/RECEIPTS.md.
Repository layout
worker/— the Cloudflare Worker serving the API, MCP endpoint, discovery files, console and playground (worker/src/), plus QA harness (qa.mjs,qa_live.mjs) and a red-team suite (worker/redteam/)engine/— Rust (workers-rs) compute plane: batch XDR-1 receipt verification (/verify-batch), key recovery, and a measured benchmark endpoint; deployed via GitHub Actionswell-known/— the discovery documents served at/.well-known/*
License
MIT
