# verify402

> Per-call truth checks for trading agents. Free pre-signing gate plus
> paid, evidence-backed verdicts: is this arbitrage real, is this token
> safe, is this quote fair, and how much can my size move.

Live: https://verify402.onrender.com
Quickstart: https://verify402.onrender.com/start
Interactive Docs: https://verify402.onrender.com/docs
MCP Information: https://verify402.onrender.com/mcp
Code: https://github.com/a32116150-ctrl/verify402

## Free, no key, no wallet

- POST /preflight — PASS / CAUTION / BLOCK for a payment or a chain
  transaction, with typed reasons, the checks that ran, the checks that
  did not, and a short-lived HMAC receipt (90s default).
- POST /preflight/verify — recompute a receipt. Tampered or expired
  receipts return valid: false.
- GET /findings — free published verdicts.
- GET /health — liveness and network configuration.
- GET /info — JSON capabilities and pricing.

## Paid, x402 exact, USDC on Base mainnet or Solana

Each paid call returns a verdict with reproducible evidence and an
evidence_bundle (requestHash, responseHash, pinnedBlock). The 402
challenge is authoritative for price and payee.

- POST /verify — 0.05 USDC. Is this cross-venue arbitrage real at one
  pinned block? Most common honest answer: no_edge.
- POST /safety — 0.10 USDC. Token gate: TRUST / CAUTION / AVOID, with a
  USD-sized sell probe against every venue.
- POST /route — 0.03 USDC. Every venue quoting tokenIn to tokenOut at
  one pinned block, best first.
- POST /quotecheck — 0.05 USDC. Audit someone else's quote: fair /
  overpaying / too_good_to_be_true / unknown.
- POST /depth — 0.05 USDC. Largest size that still clears your cost
  tolerance; capacityUsd.

## Machine-readable Manifests & Discovery

- /.well-known/verify402.json — Canonical machine-readable service manifest.
- /openapi.json — OpenAPI 3.1 contract with x-payment-info on every paid route.
- /.well-known/x402 — x402 capability manifest (draft-hawkins-x402-dns-discovery-02).
- /.well-known/agent-card.json — A2A agent card (ERC-8004).
- /sitemap.xml — XML sitemap for public documentation indexers.
- MCP bridge package: verify402-mcp (stdio transport)
  Install: npx -y verify402-mcp
  npm: https://www.npmjs.com/package/verify402-mcp
  Official MCP Registry: io.github.a32116150-ctrl/verify402-mcp

## Honest boundary & Security

No profit promises. The most common verdict is no_edge, and that
negative result is the product. Verdicts ship with the pinned
block and cryptographic hashes needed to reproduce or refute them.
A PASS on preflight does not mean a transaction is universally safe;
always inspect the 'notChecked' array for unverified assumptions.