Payments · x402 · early usage

Write an on-chain attestation (Ethereum Attestation Service on Base) that binds a call…

by agent402.tools · discovered, not yet claimed by its owner · updated 2026-10-13

30d calls51

30d payers2

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Write an on-chain attestation (Ethereum Attestation Service on Base) that binds a call you paid for to the bytes you received: the tool slug, sha256 of the JSON response, the settlement chain and transaction, the payer, the time served and the price, signed by this server's wallet. Give it the settlement transaction from the PAYMENT-RESPONSE (or Payment-Receipt) header of any settled call; the attestation UID and its public page on base.easscan.org come back.

Tags: agent · attestation · eas · provenance · receipt · bazaar · builder-code · payment-identifier

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-13

Input example from Bazaar metadata

{
  "tx": "0x2f1fecade9bd945e7817c11e5a34cafe6b349dd8c92a7587efed1de476bddfeb"
}

Output example

{
  "attestTx": "0x9c8b7a6f5e4d3c2b1a0f9e8d7c6b5a4f3e2d1c0b9a8f7e6d5c4b3a2f1e0d9c8b",
  "attestationUrl": "https://base.easscan.org/attestation/view/0x5b4d0c1e8f7a4c2d9e0b6a3f1c8d7e6b5a4f3e2d1c0b9a8f7e6d5c4b3a2f1e0d",
  "attester": "0xa11ce0000000000000000000000000000000a402",
  "block": "50829611",
  "chain": "eip155:8453",
  "data": {
    "payer": "0xb0b0000000000000000000000000000000000b0b",
    "priceUsd": 0.01,
    "responseSha256": "0x7d2a9b1c4e6f8a0b2c4d6e8f0a1b3c5d7e9f1a3b5c7d9e1f3a5b7c9d1e3f5a7b",
    "servedAt": "2026-09-03T15:16:06.000Z",
    "settlementNetwork": "eip155:8453",
    "settlementTx": "0x2f1fecade9bd945e7817c11e5a34cafe6b349dd8c92a7587efed1de476bddfeb",
    "slug": "crypto-price"
  },
  "eas": "0x4200000000000000000000000000000000000021",
  "existing": false,
  "schema": "string slug,bytes32 responseSha256,string settlementNetwork,string settlementTx,string payer,uint64 servedAt,uint64 priceMicroUsd",
  "schemaUid": "0x2a4e6c8d0f1b3a5c7e9d1f3b5a7c9e1d3f5b7a9c1e3d5f7b9a1c3e5d7f9b1a3c",
  "uid": "0x5b4d0c1e8f7a4c2d9e0b6a3f1c8d7e6b5a4f3e2d1c0b9a8f7e6d5c4b3a2f1e0d",
  "verify": {
    "attestation": "fetch the UID on https://base.easscan.org (or read EAS 0x4200000000000000000000000000000000000021 on Base): attester must be this server's wallet, schema must match",
    "payment": "follow settlementTx on eip155:8453: the payer paid this server's payTo",
    "responseDigest": "sha256 over the exact JSON bytes you received for that call; compare with responseSha256"
  }
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/27949.json for the price and payment options.
Pay. Call GET https://agent402.tools/api/attest. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, Polygon, Arbitrum One, eip155:143, Avalanche, eip155:1329, Optimism, eip155:4663, eip155:42220, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.05 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Polygon, Arbitrum One, eip155:143, Avalanche, eip155:1329, Optimism, eip155:4663, eip155:42220
Demand: 51 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.05	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Polygon eip155:137	USDC	$0.05	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Arbitrum One eip155:42161	USDC	$0.05	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:143 eip155:143	0x754704Bc059F8C67012fEd69BC8A327a5aafb603	50000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Avalanche eip155:43114	0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E	50000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:1329 eip155:1329	0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392	50000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Optimism eip155:10	0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85	51000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:4663 eip155:4663	0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168	50000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:42220 eip155:42220	0xcebA9300f2b948710d2653dD7B07f33A8B32118C	50000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "50000",
    "amountUsd": 0.05,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "50000",
    "amountUsd": 0.05,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "50000",
    "amountUsd": 0.05,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:143",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x754704Bc059F8C67012fEd69BC8A327a5aafb603",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:43114",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:1329",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:10",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
    "amount": "51000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:4663",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42220",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xcebA9300f2b948710d2653dD7B07f33A8B32118C",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {},
  "type": "string"
}

Examples

curl

curl "https://agent402.tools/api/attest"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://agent402.tools/api/attest");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://agent402.tools/api/attest")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: agent402.tools
Endpoint: https://agent402.tools/api/attest
Machine-readable: /resources/27949.json