{
  "x402Version": 2,
  "id": 2219,
  "slug": "2219",
  "resource": "https://agent-arcade.use.x402atlas.com/twenty-four/check",
  "description": "Twenty-Four answer check — verifies a 24-game arithmetic expression with exact rational math against the deterministic daily challenge.",
  "type": "http",
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:8453",
      "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "amount": "5000",
      "maxTimeoutSeconds": 300
    },
    {
      "scheme": "exact",
      "network": "eip155:137",
      "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
      "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
      "amount": "5000",
      "maxTimeoutSeconds": 300
    },
    {
      "scheme": "exact",
      "network": "eip155:42161",
      "payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
      "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
      "amount": "5000",
      "maxTimeoutSeconds": 300
    }
  ],
  "outputSchema": {
    "bazaar": {
      "category": "games",
      "info": {
        "input": {
          "body": {
            "answer": "12*((9-13)+6)",
            "challenge_id": "sha256:91ea634735ae4ff57c83ef8f3f08fdecf0b146d41582264bdcbb64b560f36cce",
            "date": "2026-07-01",
            "difficulty": "normal",
            "generation_version": "v1"
          },
          "bodyType": "json",
          "method": "POST",
          "type": "http"
        },
        "output": {
          "example": {
            "challenge_id": "sha256:91ea634735ae4ff57c83ef8f3f08fdecf0b146d41582264bdcbb64b560f36cce",
            "correct": true,
            "feedback": {
              "message": "correct: the expression evaluates to exactly 24",
              "numbers_used": [
                12,
                9,
                13,
                6
              ]
            },
            "game": "twenty-four",
            "proof": {
              "exact_value": "24",
              "normalized_expression": "(12 * ((9 - 13) + 6))",
              "numbers_used": [
                12,
                9,
                13,
                6
              ]
            },
            "score": 100,
            "valid": true
          },
          "type": "json"
        }
      },
      "schema": {
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "properties": {
          "input": {
            "additionalProperties": false,
            "properties": {
              "body": {
                "additionalProperties": false,
                "description": "Twenty-Four answer-check request using the identity from a daily challenge.",
                "properties": {
                  "answer": {
                    "description": "Twenty-Four arithmetic expression using each supplied number exactly once with + - * / and parentheses, evaluating to exactly 24",
                    "maxLength": 256,
                    "type": "string"
                  },
                  "challenge_id": {
                    "description": "The challenge_id from the daily envelope (sha256:...)",
                    "pattern": "^sha256:[0-9a-f]{64}$",
                    "type": "string"
                  },
                  "date": {
                    "description": "UTC challenge date (YYYY-MM-DD)",
                    "format": "date",
                    "pattern": "^\\d{4}-\\d{2}-\\d{2}$",
                    "type": "string"
                  },
                  "difficulty": {
                    "description": "Challenge difficulty",
                    "enum": [
                      "normal"
                    ],
                    "type": "string"
                  },
                  "generation_version": {
                    "description": "Pinned generator version of the referenced challenge",
                    "enum": [
                      "v1"
                    ],
                    "type": "string"
                  }
                },
                "required": [
                  "challenge_id",
                  "generation_version",
                  "date",
                  "difficulty",
                  "answer"
                ],
                "type": "object"
              },
              "bodyType": {
                "enum": [
                  "json",
                  "form-data",
                  "text"
                ],
                "type": "string"
              },
              "method": {
                "enum": [
                  "POST"
                ],
                "type": "string"
              },
              "type": {
                "const": "http",
                "type": "string"
              }
            },
            "required": [
              "type",
              "method",
              "bodyType",
              "body"
            ],
            "type": "object"
          },
          "output": {
            "properties": {
              "example": {
                "additionalProperties": false,
                "description": "Twenty-Four answer-check verdict.",
                "properties": {
                  "challenge_id": {
                    "description": "Canonical ID of the checked challenge",
                    "type": "string"
                  },
                  "correct": {
                    "description": "The expression solves the challenge (equals 24 exactly)",
                    "type": "boolean"
                  },
                  "feedback": {
                    "additionalProperties": false,
                    "description": "Validity feedback; never contains a solution the client did not produce",
                    "properties": {
                      "message": {
                        "type": "string"
                      },
                      "numbers_used": {
                        "items": {
                          "type": "integer"
                        },
                        "type": "array"
                      }
                    },
                    "required": [
                      "message",
                      "numbers_used"
                    ],
                    "type": "object"
                  },
                  "game": {
                    "description": "Twenty-Four game identity.",
                    "enum": [
                      "twenty-four"
                    ],
                    "type": "string"
                  },
                  "proof": {
                    "additionalProperties": false,
                    "description": "Present only when correct: the client's own verified expression, normalized, with its exact value",
                    "properties": {
                      "exact_value": {
                        "type": "string"
                      },
                      "normalized_expression": {
                        "type": "string"
                      },
                      "numbers_used": {
                        "items": {
                          "type": "integer"
                        },
                        "type": "array"
                      }
                    },
                    "required": [
                      "normalized_expression",
                      "exact_value",
                      "numbers_used"
                    ],
                    "type": "object"
                  },
                  "score": {
                    "description": "Informational score: 100 correct, 0 otherwise",
                    "type": "integer"
                  },
                  "valid": {
                    "description": "The expression follows the rules",
                    "type": "boolean"
                  }
                },
                "required": [
                  "challenge_id",
                  "game",
                  "valid",
                  "correct",
                  "score",
                  "feedback"
                ],
                "type": "object"
              },
              "type": {
                "type": "string"
              }
            },
            "required": [
              "type"
            ],
            "type": "object"
          }
        },
        "required": [
          "input"
        ],
        "type": "object"
      },
      "tags": [
        "twenty-four",
        "24-game",
        "math-puzzle",
        "arithmetic",
        "reasoning",
        "agent-benchmark",
        "answer-check"
      ]
    }
  },
  "tags": [
    "bazaar"
  ],
  "sourceHost": "agent-arcade.use.x402atlas.com",
  "lastUpdated": "2026-09-15T06:32:15.56Z",
  "quality": {
    "calls30d": 8,
    "uniquePayers30d": 5,
    "lastCalledAt": "2026-09-15T06:32:15.444Z"
  },
  "liveness": {},
  "verified": false,
  "featured": false,
  "provider": {
    "host": "agent-arcade.use.x402atlas.com",
    "manifest_name": "agent-arcade.use.x402atlas.com",
    "source": "cdp-mirror",
    "source_manifest_url": "https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources",
    "submitted_at": "2026-09-18T22:00:31.484Z"
  }
}