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Identity & Enrichment · x402 · early usage

Keccak Merkle tree and proof builder — generate indexed sorted-pair inclusion proofs wi…

Keccak Merkle tree and proof builder — generate indexed sorted-pair inclusion proofs with domain separation and explicit odd-node promotion.

by chain-tools.use.x402atlas.com · discovered, not yet claimed by its owner · updated 2026-10-01

30d calls3
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

Keccak Merkle tree and proof builder — generate indexed sorted-pair inclusion proofs with domain separation and explicit odd-node promotion.

Tags: merkle-proof · merkle-tree · keccak256 · proof-generation · blockchain-development · bazaar

Call contract

Method
POST
Input
json
Output
json
Last paid call
2026-10-01
Input example from Bazaar metadata
{
  "leaves": [
    "0x616c706861",
    "0x62657461",
    "0x67616d6d61"
  ]
}
Output example
{
  "algorithm_version": "keccak256-sorted-pairs-v1",
  "leaf_count": 3,
  "leaf_hashes": [
    "0x180a512e153366b1510bf090b11069c19394ab868093ef5290ead07f1fbb3386",
    "0x5b3931176fc5f22736bfc5393315c63244f57e672b5017c675220ec7de504ae6",
    "0xe51a809d0bd7c39f11aa7f9ff0ba85099028c7d56f42313f3bb5495a7b967146"
  ],
  "operation": "merkle-build",
  "proofs": [
    {
      "index": 0,
      "steps": [
        {
          "hash": "0x5b3931176fc5f22736bfc5393315c63244f57e672b5017c675220ec7de504ae6"
        },
        {
          "hash": "0xe51a809d0bd7c39f11aa7f9ff0ba85099028c7d56f42313f3bb5495a7b967146"
        }
      ]
    },
    {
      "index": 1,
      "steps": [
        {
          "hash": "0x180a512e153366b1510bf090b11069c19394ab868093ef5290ead07f1fbb3386"
        },
        {
          "hash": "0xe51a809d0bd7c39f11aa7f9ff0ba85099028c7d56f42313f3bb5495a7b967146"
        }
      ]
    },
    {
      "index": 2,
      "steps": [
        {
          "hash": "0xbfa0350c48ccd55fb3a8315a6d6bfc41877772eaebfcba73cb195984df5b3d32"
        }
      ]
    }
  ],
  "root": "0x40a0fa2d0ce898ef138c3403645be77705df9d485ecc137b02b35eb9fdeaaf94",
  "warnings": []
}

Use with an agent

  1. Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
  2. Inspect. Fetch /resources/28639.json for the price and payment options.
  3. Pay. Call GET https://chain-tools.use.x402atlas.com/merkle/build. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
  4. 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, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price
$0.01 / request
Protocol
x402 v2
Auth
No account or API key. Pay per request.
Networks
Base, Polygon, Arbitrum One
Demand
3 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

SchemeNetworkAssetAmountPay toTimeout
exactBase
eip155:8453		USDC$0.010x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2300s
exactPolygon
eip155:137		USDC$0.010x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2300s
exactArbitrum One
eip155:42161		USDC$0.010x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2300s
accepts[] (raw JSON)
[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)
{
  "properties": {
    "example": {
      "additionalProperties": false,
      "properties": {
        "_atlas": {
          "additionalProperties": false,
          "description": "Atlas documentation and related-route metadata added after deployment",
          "properties": {
            "docs": {
              "description": "Documentation URL for this bridge",
              "format": "uri",
              "maxLength": 512,
              "type": "string"
            },
            "related": {
              "description": "Bounded related Atlas routes",
              "items": {
                "additionalProperties": false,
                "description": "One related Atlas route",
                "properties": {
                  "bridge": {
                    "description": "Related bridge name",
                    "maxLength": 64,
                    "type": "string"
                  },
                  "docs": {
                    "description": "Related bridge documentation URL",
                    "format": "uri",
                    "maxLength": 512,
                    "type": "string"
                  },
                  "summary": {
                    "description": "Short capability summary",
                    "maxLength": 256,
                    "type": "string"
                  },
                  "url": {
                    "description": "Related route URL",
                    "format": "uri",
                    "maxLength": 512,
                    "type": "string"
                  }
                },
                "required": [
                  "bridge",
                  "url",
                  "docs",
                  "summary"
                ],
                "type": "object"
              },
              "maxItems": 3,
              "type": "array"
            }
          },
          "required": [
            "docs"
          ],
          "type": "object"
        },
        "algorithm_version": {
          "const": "keccak256-sorted-pairs-v1",
          "description": "Atlas domain-separated sorted-pair profile",
          "type": "string"
        },
        "leaf_count": {
          "description": "Number of original leaves",
          "maximum": 1024,
          "minimum": 1,
          "type": "integer"
        },
        "leaf_hashes": {
          "description": "Domain-separated leaf hashes in original order",
          "items": {
            "description": "Leaf hash",
            "pattern": "^0x[0-9a-f]{64}$",
            "type": "string"
          },
          "maxItems": 1024,
          "minItems": 1,
          "type": "array"
        },
        "operation": {
          "const": "merkle-build",
          "description": "Stable route operation",
          "type": "string"
        },
        "proofs": {
          "description": "Exactly one proof for every original index",
          "items": {
            "additionalProperties": false,
            "properties": {
              "index": {
                "description": "Zero-based original leaf index",
                "maximum": 1023,
                "minimum": 0,
                "type": "integer"
              },
              "steps": {
                "description": "Sibling hashes in leaf-to-root order; odd promotions add no step",
                "items": {
                  "additionalProperties": false,
                  "properties": {
                    "hash": {
                      "description": "Sibling node hash; direction is unnecessary because pairs sort by hash",
                      "pattern": "^0x[0-9a-f]{64}$",
                      "type": "string"
                    }
                  },
                  "required": [
                    "hash"
                  ],
                  "type": "object"
                },
                "maxItems": 10,
                "type": "array"
              }
            },
            "required": [
              "index",
              "steps"
            ],
            "type": "object"
          },
          "maxItems": 1024,
          "minItems": 1,
          "type": "array"
        },
        "root": {
          "description": "Tree root",
          "pattern": "^0x[0-9a-f]{64}$",
          "type": "string"
        },
        "warnings": {
          "description": "Always empty",
          "items": {
            "description": "Warning",
            "type": "string"
          },
          "maxItems": 0,
          "type": "array"
        }
      },
      "required": [
        "operation",
        "algorithm_version",
        "leaf_count",
        "root",
        "leaf_hashes",
        "proofs",
        "warnings"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}
Example shape — generated from the schema, not a captured live response
{
  "example": {
    "_atlas": {
      "docs": "https://example.com",
      "related": [
        {
          "bridge": "string",
          "docs": "https://example.com",
          "summary": "string",
          "url": "https://example.com"
        }
      ]
    },
    "algorithm_version": "string",
    "leaf_count": 0,
    "leaf_hashes": [
      "string"
    ],
    "operation": "string",
    "proofs": [
      {
        "index": 0,
        "steps": [
          {
            "hash": "string"
          }
        ]
      }
    ],
    "root": "string",
    "warnings": [
      "string"
    ]
  },
  "type": "string"
}

Examples

curl
curl "https://chain-tools.use.x402atlas.com/merkle/build"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://chain-tools.use.x402atlas.com/merkle/build");
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://chain-tools.use.x402atlas.com/merkle/build")
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
chain-tools.use.x402atlas.com
Endpoint
https://chain-tools.use.x402atlas.com/merkle/build
Machine-readable
/resources/28639.json