Evidence row 290921

What was observed

{
  "count": 2,
  "tools": [
    {
      "description": "List available KDP niche keywords ordered by demand score.\n\n    Use this to discover what Kindle publishing niches are available for\n    detailed research. Returns keywords ordered by demand score (highest first).\n\n    This endpoint is free — no payment required.\n\n    Args:\n        limit: Number of results to return (1-100, default 20)\n        offset: Pagination offset (default 0)\n    ",
      "inputSchema": {
        "properties": {
          "limit": {
            "default": 20,
            "title": "Limit",
            "type": "integer"
          },
          "offset": {
            "default": 0,
            "title": "Offset",
            "type": "integer"
          }
        },
        "title": "list_nichesArguments",
        "type": "object"
      },
      "name": "list_niches"
    },
    {
      "description": "Get detailed KDP niche intelligence for a specific keyword.\n\n    Returns demand score, competition score, Amazon BSR range, estimated\n    monthly revenue, review threshold, average book pricing, and data\n    freshness for the given Kindle publishing niche.\n\n    Pricing tiers (x402 USDC on Base network):\n      - $0.03 per query for cached/pre-seeded keywords\n      - $0.10 per query for live on-demand research (new keywords)\n\n    Use the free `list_niches` tool first to see available keywords.\n\n    Payment options:\n      1. Set the KDP_X_PAYMENT environment variable on the server for auto-pay.\n      2. Pass a valid x402 payment header via the x_payment argument.\n      3. If neither is set, the tool returns structured 402 payment instructions\n         that an x402-capable agent can use to construct and retry payment.\n\n    Args:\n        keyword: The KDP niche keyword to research (e.g. \"romance novels\", \"keto cookbook\")\n        x_payment: Optional base64-encoded x402 payment header. Takes precedence\n                   over the KDP_X_PAYMENT environment variable.\n    ",
      "inputSchema": {
        "properties": {
          "keyword": {
            "title": "Keyword",
            "type": "string"
          },
          "x_payment": {
            "default": "",
            "title": "X Payment",
            "type": "string"
          }
        },
        "required": [
          "keyword"
        ],
        "title": "research_nicheArguments",
        "type": "object"
      },
      "name": "research_niche"
    }
  ]
}

What the leaf hashes

{"body":"f276d0066cc61769653c86eb48855e7169d78f4c9225faf68314368934405321","id":290921,"kind":"mcp.tools","method":"probe.mcp/1","observed_us":1793047648282662,"prev":null,"subject":"f8381b3b-df4e-4e23-abb8-5766c6f8c2dd","subject_kind":"endpoint"}

Proof

Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of 2026-10-26 (296695 rows).

1. 0xd2ed4e5cea31b23c34d0354a180d9cee642123a5926d0401a77c2d9a97db36be
2. 0x2a3bcf6b9865050f062b17ce8e32f563ea6b0f702fd5e5f7edc0a214265e351d
3. 0x44deb6967def520931ad9477a7c9ef3b813e370fb4364987cb718f376b726e18
4. 0xb5866ef79d3f11e03f608fbd092927b7fda319e73792fc06ce4438c2a1b867f1
5. 0x4b2940e58e5235a2440f9df4cc78feaa6236819b5e5c757c315d3bca74bfa084
6. 0xf3004f2a53ae31d4c3e1a384e26adb9d3e6380c1ac22c369f9b61d642d1d4f2c
7. 0x4d6a23548810a2b7cb005f626acb8ec11e8e2da1809e0923d24380c69f9acffa
8. 0xd02ffcd1d3341d0f2878ea7f1f124b9a41d0cacbf11e53f4af6e70bdf003f0ce
9. 0xd65e1c4268c254c75099d68c1504a1cd79c8b8ec7c71dd13bab41759420b9878
10. 0x23281d709cf04c855d24d0ddda1eeee00e3764cd2f480e88d171dd0d6536c42d
11. 0xeaf3195c275963f3eeb4749105d68120537a7f4d52fd74b2b409cf37abd6484b
12. 0x9f6b360f1992898cb3f17e45d0bf5a96f946d7eaf9705a57af03c151a407d239
13. 0x889eefefef2d4457fe6114f397df813a5cbb85011a6f40309b54ddcd4aba3bd1
14. 0xefabf1105e09cf52c12c58e60cbb5048b9ac3f02631d1816a926e14bdd86fbdf
15. 0xe94ca5b798e9899ad611e57835af42266e20f53f44977e487d81365e30972beb
16. 0x703f95866af09c5e5d6ead7411e9a10f964a41a2aff64d4a55ff0053c023a023
17. 0xd0651cb9bc8155eb52b5247d506e74b8a935057dc190ba52091702ac25ed3a40
18. 0x9a9024edb5069d88a324facb310a5ce8e495214bbaa968f077bede437390194f
19. 0x9b9ce5b74b9bab5121612ef6b64920a8d453cbf311096a423eef9702747e868a

Day root

0xf43e8dcc3d451a4788b26be904c55e8c4c0fa75c9666796c51db38d37e2c0df8

Chained

0x702d5ac508f08b0d1accf36af25822d8e5660367494edd17a642fb61e158a57a

Published

On Arc Testnet, block 69251483: 0x495162f8936e19f0039918feebe6c307f327cd6bf8c37219620b1970041fa9ae