# BriefGuard

BriefGuard is a deterministic, stateless acceptance-audit API for agents and builders. It maps supplied requirements to supplied evidence, flags missing proof and ambiguous language, and returns a stable fingerprint. It does not execute or independently verify the underlying artifact.

## Endpoints

- `POST /api/preview` — free; at most five requirements.
- `GET /api/audit` — free machine contract and limits.
- `POST /api/audit` — full audit for up to 80 requirements; exact 5.25 USDC via x402 v2 on Base mainnet.
- `GET /openapi.json` — OpenAPI 3.1 contract.
- `GET /.well-known/x402` — x402 payment and input metadata.
- `GET /manifest.json` — portable `agent402/manifest@1` provider manifest.

## Payment

Send the JSON request once. A client without payment receives HTTP 402 and a `PAYMENT-REQUIRED` header. Sign the exact USDC authorization described there, retry with `PAYMENT-SIGNATURE`, and read the settlement transaction from `PAYMENT-RESPONSE`.

## Privacy and limits

No storage, no cookies, no model calls, and no secret credentials are needed. Request bodies are capped at 64 KB. Do not submit confidential information.