Evidence row 266755

What was observed

{
  "count": 3,
  "tools": [
    {
      "description": "The current value of one official figure by key — a tax threshold, rate, allowance, fee, deadline, limit or policy rate — with the date it was verified, the official source URL, the period it applies to and a signature. Keys are `<country>/<topic>/<fact>`, e.g. `uk/income-tax/personal-allowance`, `uk/national-insurance/primary-threshold`, `us/social-security/wage-base`, `de/income-tax/grundfreibetrag`, `uk/bank-rate`, `eu/ecb/deposit-facility`, `uk/gov/passport-renewal-adult/fee-online-uk`. A loose key is resolved when unambiguous; otherwise the answer lists candidate keys. `max_age` (e.g. `30d`) marks the answer `stale` when the verification is older than that. Several keys separated by commas return a batch. Covers UK, US and German rates and thresholds, UK vehicle tax and MOT rules, UK government service fees, UK exam dates and central-bank policy rates; `coverage` lists the rest.",
      "inputSchema": {
        "properties": {
          "as_of": {
            "description": "optional YYYY-MM-DD: the value in force that day",
            "format": "date",
            "type": "string"
          },
          "key": {
            "description": "one key, or several separated by commas (max 50), e.g. uk/income-tax/personal-allowance",
            "type": "string"
          },
          "max_age": {
            "description": "optional freshness bar: 30d, 12w, 6m, 1y or ISO 8601 (P30D)",
            "type": "string"
          },
          "period": {
            "description": "optional period label instead of as_of, e.g. 2025-26",
            "type": "string"
          }
        },
        "required": [
          "key"
        ],
        "type": "object"
      },
      "name": "get_fact"
    },
    {
      "description": "Ranked canonical fact keys for a plain-language question or a guessed key — \"NI primary threshold\", \"ECB deposit rate\", \"passport renewal fee\" — each with label, unit, period and verification date, and the full record of the top match when it is unambiguous. The keys feed `get_fact`. Filter by `namespace` (`uk`, `us`, `de`, `eu`).",
      "inputSchema": {
        "properties": {
          "limit": {
            "description": "default 5",
            "maximum": 20,
            "minimum": 1,
            "type": "integer"
          },
          "namespace": {
            "description": "optional jurisdiction filter",
            "enum": [
              "de",
              "eu",
              "jp",
              "uk",
              "us"
            ],
            "type": "string"
          },
          "q": {
            "description": "question or guessed key",
            "type": "string"
          }
        },
        "required": [
          "q"
        ],
        "type": "object"
      },
      "name": "resolve_fact"
    },
    {
      "description": "What has changed in Data Butler's verified datasets since a date — pass your training-cutoff date to learn which UK tax/NI/benefit thresholds, exam-spec facts, official vehicle datasets (UK DVSA, French RappelConso and Japanese MLIT recalls), software end-of-life dates (Node.js, Python, Ubuntu, Debian, Android, iOS, macOS, Windows, Java, Go, Ruby, PHP, PostgreSQL, React — cycles that reached end of life or whose dates moved), central-bank policy rates (Bank of England, Fed, ECB), US federal tax thresholds (IRS inflation adjustments, Social Security wage base, retirement and HSA limits), German tax and social-insurance thresholds (Grundfreibetrag, Beitragsbemessungsgrenzen, Zusatzbeitrag, Mindestlohn, Kindergeld), UK vehicle tax (VED) rates and MOT rules, UK exam dates (results days, summer timetable paper dates, entry deadlines and late-fee dates, announced specification changes), calendar facts (public holidays for the UK, US, Germany and France; tax-year and daylight-saving rules for nine countries — new years published, holidays added or moved), UK government service fees and rules (passports, ETA, Universal Credit, eVisa), Japanese vehicle statutory costs (車検 inspection fees, 自賠責 insurance rates) and Japanese minimum wages by prefecture, 協会けんぽ health insurance rates, 雇用保険料率 and income-tax deductions changed after your knowledge ends. Each entry: from → to, effectiveFrom, official source, verifiedDate, and a maintainer note (e.g. which Budget). Areas: uk-rates, uk-exams, vehicles, software-eol, policy-rates, us-rates, de-rates, uk-vehicle-rules, uk-exam-dates, calendar, uk-gov-process, jp-vehicle-costs, jp-living-costs, or all. Coverage starts 2026-08-31. The same changelog is published for humans at https://databutler.dev/changes, with feeds at https://databutler.dev/changes.rss and https://databutler.dev/changes.atom. Output is a Verified Changes protocol document (verified-changes/0.1, spec https://databutler.dev/protocol); an entry whose figure is a Verified Fact carries factKey for get_fact.",
      "inputSchema": {
        "properties": {
          "area": {
            "description": "default all",
            "enum": [
              "uk-rates",
              "uk-exams",
              "vehicles",
              "software-eol",
              "policy-rates",
              "us-rates",
              "de-rates",
              "uk-vehicle-rules",
              "uk-exam-dates",
              "calendar",
              "uk-gov-process",
              "jp-vehicle-costs",
              "jp-living-costs",
              "all"
            ],
            "type": "string"
          },
          "since": {
            "description": "ISO date YYYY-MM-DD, e.g. your training cutoff",
            "type": "string"
          }
        },
        "required": [
          "since"
        ],
        "type": "object"
      },
      "name": "what_changed_since"
    }
  ]
}

What the leaf hashes

{"body":"ae699a9b1ad6b9d0491f5085ae647f3c4171138476aaa373f22bec4074c02fd5","id":266755,"kind":"mcp.tools","method":"probe.mcp/1","observed_us":1793035517479685,"prev":null,"subject":"81117107-4bef-4787-8fdf-b3a3eea8de04","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. 0x3031e10d182d8cbb953a91b0ad5ed11547c57852d75b403e3e696689d0678d11
2. 0xab643d8b351438d37c11e21ba5adc60b8808af4bf850f23338ddb1857c0134be
3. 0x702443c001e0627c8b74dbcf5959debb6b6ed5bdf48f497ca1153e805411e771
4. 0x2135478a56b11ca6290aab255042b173918db4440c01689bacd23e08ca828856
5. 0xfa598d7c5805add2e19cc1b89f9b3f8bc3ccb0cdecfc8d513c04fd82be1cf3e0
6. 0x8f23f126948bbddcbcf7b797b7ac3d1c7c4ebaeb38949260280a6df549b8da03
7. 0xe90af66235d2cc0f9493fc0f80698b6cdf88da6c881f846583536991fc44990c
8. 0x026dd6b1e4a6d5e84058c0d73bff885d38025cf22c25b29fbf607c1e86dd181a
9. 0x4c3f3c54cb86f615c8f89498ef5aa0197e36f3c3340d5b27d8cc5216ae000be0
10. 0xfc41c6565c167c5fee646cb3779bde7c2fc51d01a9e07093c87ead9e962c2976
11. 0x66b4d790d6ae725a0af009d5a6edacaec5a6147d597bc8410a97be11d56a00d1
12. 0xd85c7204d76d26255c94ef4caa12c05addd08238caa5cdc3888ea60b74e6b940
13. 0x36a44931b230976c04691d90bf3a25ed4111d74c78b672850d8025a911ca88dd
14. 0x683955a5b2250ad50568d022a6580d8739b6aff1356779d72a773b088e7c289c
15. 0x610738e0c43687aded83c613c73de8b5226c73c375858a167436461c522ea213
16. 0x06d71bfa7d8b41d62c8836efc2c601e1cc3772d9453596b2ae4950887f3310ca
17. 0x8c756542e482157df0c36464d75c937b845e4423dbbcfad08f0cf8d5a16b9a13
18. 0x20704208aa6923d6b2450ef74ede87a6e0265d46447926038fe9506e9e154b2d
19. 0x9b9ce5b74b9bab5121612ef6b64920a8d453cbf311096a423eef9702747e868a

Day root

0xf43e8dcc3d451a4788b26be904c55e8c4c0fa75c9666796c51db38d37e2c0df8

Chained

0x702d5ac508f08b0d1accf36af25822d8e5660367494edd17a642fb61e158a57a

Published

On Arc Testnet, block 69251483: 0x495162f8936e19f0039918feebe6c307f327cd6bf8c37219620b1970041fa9ae