# CounterpartyCheck

One-call counterparty screen, agent-callable. Before your agent pays, onboards or trades with a wallet it doesn't know, one call runs the full check a compliance desk would: exact match against the ~500 crypto addresses on the US Treasury OFAC SDN list, an optional OFAC name/entity screen, on-chain wallet risk (GoPlus flags: sanctioned, mixer, phishing, money laundering) and a wallet profile (portfolio, first seen, activity, exchange contacts, address-poisoning signs). Returns one PASS / REVIEW / BLOCK with reasons and warnings, signed as an LSO Receipt (secp256k1 / EIP-191): ethers.verifyMessage must recover the signer published at /signer. $0.25 via x402 on Base or Solana (the same three checks bought separately cost $0.30). | Full catalog: lonestaroracle.xyz

Base URL: https://counterparty.lonestaroracle.xyz
Payment: x402 micropayment in USDC on Base (eip155:8453) or Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp); a 402 response returns payment terms.

## Endpoints
### GET /screen
Params: wallet (address; or name), name (optional), chain (optional: auto|eth|base|arb|poly|bsc, default auto = checks Ethereum and Base, profiles the active one). Aliases: address, agent, entity, q, network.
### GET /signer (free)
The receipt signer address and how to verify a receipt.

## Related services
- KYACheck (kya.lonestaroracle.xyz, $0.10) - OFAC + wallet risk only
- SanctionsScreen (sanctions.lonestaroracle.xyz, $0.05) - OFAC name/entity screening only
- WalletIntel (wallet.lonestaroracle.xyz, $0.15) - full wallet report

Agent manual (SKILL.md): https://counterparty.lonestaroracle.xyz/SKILL.md