# Pay Guard

> Pre-payment allow/warn/block for x402 + Seller Wallet Reputation. Deterministic, no LLM.

## Endpoints
- POST https://seenly-pay-guard.vercel.app/api/guard — $0.01 USDC — $0.01 USDC per call on Base mainnet.
- POST https://seenly-pay-guard.vercel.app/api/reputation — $0.02 USDC — $0.02 USDC per call on Base mainnet.

## Pay Guard body
```json
{"domain":"example.com","max_price_usd":0.05,"challenge":{"payTo":"0x...","amount":"10000","network":"eip155:8453","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","resource":"https://example.com/api"}}
```
Returns `{verdict: allow|warn|block, reasons, checks}`. Missing Agentropolis data → **warn** (not block).

## Reputation body
```json
{"payTo":"0x...","domain":"optional.example.com"}
```
Returns distinct buyers, top-buyer share, wash flags, first/last settlement, verified domains, trust score. Says when coverage is limited.

## Payment
Unpaid → HTTP 402 with PAYMENT-REQUIRED (x402 v2 exact, USDC Base). Settles only on 2xx. 422 before payment on bad input.

## Free daily allowance (opt-in)
- 5 free calls per caller per UTC day (caller = client network: IPv4 /24, IPv6 /64), and at most 150 free calls per day across all callers. Shared across /api/guard and /api/reputation.
- Opt in per request with header "X-Free-Allowance: use" (or ?free=1). Without it you always get the normal x402 402.
- Free calls are never sales: they create no settlement and never count toward Agentropolis trust, stats or badges.
- Example: curl -s https://seenly-pay-guard.vercel.app/api/guard -H 'content-type: application/json' -H 'X-Free-Allowance: use' -d '{"domain":"example.com","max_price_usd":0.05,"challenge":{"payTo":"0xeee...","amount":"10000","network":"eip155:8453","resource":"https://example.com/x"}}'


## Discovery
- https://seenly-pay-guard.vercel.app/openapi.json
- https://seenly-pay-guard.vercel.app/.well-known/x402
- https://seenly-pay-guard.vercel.app/.well-known/kits.json
- https://seenly-pay-guard.vercel.app/kit.json
- https://seenly-pay-guard.vercel.app/.well-known/agent-card.json