# ReceiptSure

Deterministic Base transaction receipt verification against a declared intent, paid per call.

ReceiptSure is the other half of a transaction preflight: not what a transaction will do, but what it actually did. It fetches the receipt, decodes every Transfer, TransferSingle, TransferBatch and Approval log, and holds them against the transfers the caller said they intended — reporting each one as matched, missing or short, with the shortfall quantified in base units and in display units where the token's decimals are readable. It catches the cases a status code hides: a revert whose reason the receipt does not carry, a transaction that succeeded while moving nothing, a token that skimmed a fee on the way through, and funds leaving a declared sender for an address nobody named. There is no model anywhere in it, and a receipt it cannot read comes back as unknown rather than as approval.

## Payment

- Protocol: x402 V2, scheme `exact`, network `eip155:8453` (Base mainnet)
- Asset: USDC `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`
- No accounts, no API keys, no subscriptions.
- Failed calls are not charged. Only a successful, usable result settles.
- Payment authorization window: 60s

## Endpoints

### `POST /v1/tx/receipt-verify` — $0.01 per successful call

Check whether a mined Base transaction did what your agent meant it to do. Fetches the receipt, decodes its ERC-20, ERC-721 and ERC-1155 transfer and approval logs, and reports each declared movement as matched, missing or short, with the observed amount beside the expected one. Catches reverts, success with no effect, fee-on-transfer skims and transfers to recipients you never named. Returns unknown rather than guessing. Not a guarantee that a transaction was safe.

Unpaid request returns HTTP 402 with the challenge in the `PAYMENT-REQUIRED` header:

```bash
curl -i -sS -X POST https://receipt.schemasure.com/v1/tx/receipt-verify \
  -H 'content-type: application/json' \
  -d '{"tx_hash":"0x7f1c3a58e0b94d26c5af7318d0e42b96c1d85f0a3b72e648d9c05147ae2b6f30","expected_transfers":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","from":"0x9F2C5E4A8db1C3a7E6B0d4f8C1E2a5b7D9C0e3F4","to":"0x5d3e1a9b7c2f4e8a0b6d3c5f9e1a7b4d2c8f0a6e","amount":"10000"}]}'
```

Example successful response:

```json
{
  "ok": true,
  "verdict": "block",
  "confidence": 1,
  "risk_codes": [
    "AMOUNT_MISMATCH",
    "FEE_ON_TRANSFER_SKIM"
  ],
  "evidence": [
    {
      "code": "AMOUNT_MISMATCH",
      "severity": "critical",
      "detail": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E received 9900 base units, short of the declared 10000 by 100 base units.",
      "source": "intent-match",
      "data": {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
        "expected_base_units": "10000",
        "observed_base_units": "9900",
        "delta_base_units": "-100",
        "shortfall_base_units": "100",
        "shortfall_display": null,
        "decimals": null,
        "symbol": null
      }
    },
    {
      "code": "FEE_ON_TRANSFER_SKIM",
      "severity": "medium",
      "detail": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4 sent 10000 base units of 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 but 0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E received 9900. The missing 100 (1.00%) went to 1 other address(es) in the same transfer chain, which is the signature of a fee-on-transfer token.",
      "source": "skim",
      "data": {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
        "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
        "sent_base_units": "10000",
        "received_base_units": "9900",
        "skimmed_base_units": "100",
        "implied_fee_bps": 100,
        "plausible_fee_ceiling_bps": 1000,
        "other_recipients": [
          {
            "to": "0x4CbE9fd4a2B7c0e1D8f3A6b9C2E5d8F1A4B7C0e3",
            "amount": "100"
          }
        ]
      }
    }
  ],
  "result": {
    "tx_hash": "0x7f1c3a58e0b94d26c5af7318d0e42b96c1d85f0a3b72e648d9c05147ae2b6f30",
    "chain": "eip155:8453",
    "receipt": {
      "status": "success",
      "block_number": "0x1f4a2c0",
      "transaction_index": 12,
      "gas_used": "0xd6d8",
      "from": "0x9F2C5E4A8db1C3a7E6B0d4f8C1E2a5b7D9C0e3F4",
      "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "contract_address": null,
      "log_count": 2,
      "detail": "mined in block 0x1f4a2c0 with status 1 and 2 log(s)"
    },
    "revert": {
      "reverted": false,
      "reason": null,
      "kind": null,
      "raw": null,
      "detail": "the receipt reports status 1, so the transaction was applied"
    },
    "effect": {
      "has_logs": true,
      "decoded_logs": 2,
      "undecodable_logs": 0,
      "unrelated_logs": 0,
      "silent_success": false,
      "detail": "2 log(s): 2 transfer(s), 0 approval(s), 0 unrelated event(s), 0 that did not decode"
    },
    "expected_transfers": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "asset_kind": "erc20",
        "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
        "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
        "amount": "10000",
        "token_id": null
      }
    ],
    "transfer_checks": [
      {
        "expected": {
          "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
          "asset_kind": "erc20",
          "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
          "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
          "amount": "10000",
          "token_id": null
        },
        "status": "amount_mismatch",
        "amounts": {
          "expected_base_units": "10000",
          "observed_base_units": "9900",
          "delta_base_units": "-100",
          "shortfall_base_units": "100",
          "decimals": null,
          "symbol": null,
          "expected_display": null,
          "observed_display": null,
          "shortfall_display": null
        },
        "matched_log_indexes": [
          0
        ],
        "detail": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E received 9900 base units, short of the declared 10000 by 100 base units."
      }
    ],
    "observed_transfers": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "asset_kind": "erc20",
        "event": "Transfer",
        "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
        "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
        "amount": "9900",
        "token_id": null,
        "operator": null,
        "log_index": 0
      },
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "asset_kind": "erc20",
        "event": "Transfer",
        "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
        "to": "0x4CbE9fd4a2B7c0e1D8f3A6b9C2E5d8F1A4B7C0e3",
        "amount": "100",
        "token_id": null,
        "operator": null,
        "log_index": 1
      }
    ],
    "observed_approvals": [],
    "fee_on_transfer": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "from": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4",
        "to": "0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E",
        "sent_base_units": "10000",
        "received_base_units": "9900",
        "skimmed_base_units": "100",
        "implied_fee_bps": 100,
        "implied_fee_percent": "1.00%",
        "skimmed_display": null,
        "plausible_fee": true,
        "other_recipients": [
          {
            "to": "0x4CbE9fd4a2B7c0e1D8f3A6b9C2E5d8F1A4B7C0e3",
            "amount": "100"
          }
        ],
        "detail": "0x9f2C5E4a8DB1C3A7e6b0d4f8C1e2A5b7d9c0E3f4 sent 10000 base units of 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 but 0x5D3e1a9b7c2f4E8A0b6d3c5F9E1A7b4D2C8f0a6E received 9900. The missing 100 (1.00%) went to 1 other address(es) in the same transfer chain, which is the signature of a fee-on-transfer token."
      }
    ],
    "unexpected_recipients": [],
    "denylist_hits": [],
    "tokens": [
      {
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "symbol": null,
        "decimals": null,
        "detail": "no RPC configured, so token metadata could not be read"
      }
    ],
    "unresolved": [],
    "rpc": {
      "receipts_configured": true,
      "reads_configured": false,
      "detail": "receipts are read from the configured Base endpoints; token metadata is best-effort and never changes a verdict"
    }
  },
  "policy_version": "2026-09-19",
  "request_hash": "sha256:50864960b295fd6c1d41ddf29b9da8397286701a16480b7184a14444f0ecf1d3",
  "data_versions": {
    "denylist": "2026-08-03.1",
    "event_abis": "2026-09-19.1",
    "policy": "2026-09-19",
    "chain": "eip155:8453",
    "fee_plausibility_bps": "1000"
  },
  "warnings": [
    "No Base RPC endpoint is configured for token reads, so symbols and decimals are absent and every amount is reported in base units only. This affects presentation, never a verdict."
  ]
}
```

## Result contract

Every response is the shared portfolio envelope: `ok`, `verdict`, `confidence`, `risk_codes`,
`evidence`, `result`, `policy_version`, `request_hash`, `data_versions`, `warnings`.

`verdict: "unknown"` is a real answer, not a failure. It means the service could not determine
the result and says why in `evidence`. It is never silently reported as a safe or clean outcome.

## Service level

- Target P50: 700 ms
- Target P95: 2500 ms

## Data handling

- Caller content is processed transiently and never retained.
- No training on customer content.
- Subprocessors: base-rpc.publicnode.com (Base JSON-RPC; receives the transaction hash and token addresses being read), mainnet.base.org (Base JSON-RPC; receives the transaction hash and token addresses being read), base.gateway.tenderly.co (Base JSON-RPC; receives the transaction hash and token addresses being read)

## Machine-readable surfaces

- https://receipt.schemasure.com/openapi.json
- https://receipt.schemasure.com/.well-known/x402.json
- https://receipt.schemasure.com/.well-known/pricing.json
- https://receipt.schemasure.com/.well-known/benchmarks.json
- https://receipt.schemasure.com/.well-known/data-handling.json
- https://receipt.schemasure.com/apis.json
- https://receipt.schemasure.com/SKILL.md