Evidence row 566789

What was observed

{
  "count": 4,
  "tools": [
    {
      "description": "Compute the WCAG 2.x contrast ratio between a text (foreground) color and a background color, with pass/fail for AA, AA large text, AAA, AAA large text and non-text UI (3:1). Handles translucent colors. Read-only. Same engine as GET /api/contrast.",
      "inputSchema": {
        "additionalProperties": false,
        "properties": {
          "background": {
            "description": "Background color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
            "maxLength": 64,
            "minLength": 1,
            "type": "string"
          },
          "foreground": {
            "description": "Text / foreground color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
            "maxLength": 64,
            "minLength": 1,
            "type": "string"
          }
        },
        "required": [
          "foreground",
          "background"
        ],
        "type": "object"
      },
      "name": "check_contrast"
    },
    {
      "description": "Contrast ratio for every pair of 2 to 12 colors (up to 66 pairs), highest first, each flagged against the chosen WCAG level. Use it to see which brand colors can be used together for text. Read-only. Same engine as GET /api/palette.",
      "inputSchema": {
        "additionalProperties": false,
        "properties": {
          "colors": {
            "description": "2 to 12 CSS colors.",
            "items": {
              "description": "Palette color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
              "maxLength": 64,
              "minLength": 1,
              "type": "string"
            },
            "maxItems": 12,
            "minItems": 2,
            "type": "array"
          },
          "level": {
            "default": "aa",
            "description": "WCAG target: aa 4.5:1 (default), aa-large 3:1, aaa 7:1, aaa-large 4.5:1, ui 3:1 (non-text).",
            "enum": [
              "aa",
              "aa-large",
              "aaa",
              "aaa-large",
              "ui"
            ],
            "type": "string"
          }
        },
        "required": [
          "colors"
        ],
        "type": "object"
      },
      "name": "check_palette"
    },
    {
      "description": "Convert a CSS color to hex, rgb() and hsl(), with its relative luminance, its contrast on white and on black, and the better text color (black or white) to put on it. Read-only. Same engine as GET /api/convert.",
      "inputSchema": {
        "additionalProperties": false,
        "properties": {
          "color": {
            "description": "Color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
            "maxLength": 64,
            "minLength": 1,
            "type": "string"
          }
        },
        "required": [
          "color"
        ],
        "type": "object"
      },
      "name": "convert_color"
    },
    {
      "description": "For a failing color pair, find the closest color (same hue and saturation, lightness changed as little as possible) that meets the chosen WCAG level. Adjust the foreground (default), the background, or both (best first). Read-only. Same engine as GET /api/suggest.",
      "inputSchema": {
        "additionalProperties": false,
        "properties": {
          "adjust": {
            "default": "foreground",
            "description": "Which color may change.",
            "enum": [
              "foreground",
              "background",
              "both"
            ],
            "type": "string"
          },
          "background": {
            "description": "Background color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
            "maxLength": 64,
            "minLength": 1,
            "type": "string"
          },
          "foreground": {
            "description": "Text / foreground color as a CSS color: \"#1a73e8\", \"#fff\", \"rgb(26 115 232)\", \"hsl(217 80% 51%)\", \"rgba(0,0,0,.6)\" or a name like \"navy\".",
            "maxLength": 64,
            "minLength": 1,
            "type": "string"
          },
          "level": {
            "default": "aa",
            "description": "WCAG target: aa 4.5:1 (default), aa-large 3:1, aaa 7:1, aaa-large 4.5:1, ui 3:1 (non-text).",
            "enum": [
              "aa",
              "aa-large",
              "aaa",
              "aaa-large",
              "ui"
            ],
            "type": "string"
          }
        },
        "required": [
          "foreground",
          "background"
        ],
        "type": "object"
      },
      "name": "suggest_accessible_color"
    }
  ]
}

What the leaf hashes

{"body":"3a61657874140867a67e5982d8242ce1228881f45aaf47aeb003a1c78c140740","id":566789,"kind":"mcp.tools","method":"probe.mcp/1","observed_us":1793138534368723,"prev":null,"subject":"3e8c338b-f003-47f2-a5e8-32c78fc51620","subject_kind":"endpoint"}

Proof

Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of 2026-10-27 (273461 rows).

1. 0x7a3f0ff1b8b5099eb268d8d5617ae194a6fba0f06e15256bd27941c71d3f594b
2. 0x70ffa12c9c867c7ad066fa6def2cb2a6d74c2a7b886509e31d7abd3f8199fd3a
3. 0xe290609fffba7bf74b1d4c881d8309838be9d00befae5ae2a44424eca77895fd
4. 0x5db5691e5d33c319e98e037d034b3736cdbbb85ac1ab4446367654e5071c6923
5. 0x244427e249bbccc30f536a6ebf0da84c8a728275efdb93567b6ccab2831f4890
6. 0xd2d6d38361f25ba9b64e00f1eaf04e542f09e2025a3f5ae19aad72e97b4d8c88
7. 0x3c6b27271850fcf742a1ead4a17008f1f62aac912063c2eeba9218b1e7a7c625
8. 0x57ef9f1fb84400d3bc11e43a18323d5a71b10ac9946df2c7d24a2efd004b012b
9. 0xa2cab213aa2d823e9f94de7f447b2a92773478aeffbcd1323368337fb0c57ce6
10. 0xe9a5d1c6719d67a94924cfd78ac5d857dfe591b756d7a88a4f7a4692f2e58d71
11. 0x926531ee7b85e18ef250d5e2cf7f1fe039b14d7d9a1ebadd7e87f963de66741a
12. 0x0574b16d30fa9d3621e88c3779ea2cd142521826d4e75735f3ae6d4ed075cfc4
13. 0x8f2d125f5fe55a24b5da16577766eeaa13f24a272bb4c1c016f423ae917da681
14. 0x9848c068b1371232529d2b5738fdc45b854c57da041b69ea7c9e112b14e2d9d1
15. 0x275720ecabb68df33eee92ae4fd70572a8d952d6c61c061c2869cfc3217aa5c5
16. 0x23cf9bb4337ee8be7fcae368fd69d24c62c11fb45882127b4cd919bb96a19996
17. 0x0e01aa9525097570a6edaf32bfc959de57bf5c24317cf10c0716affea85ca60d
18. 0xa20d48798a34aba12eb9c7297722982d910f06c148f5e27ac59307422964a585
19. 0x9fc354c0ea3efc3f1b6548bb77ea902a50f2c9647647ea61592efce2bd795699

Day root

0xdd77e5e99da32c3f154180d63e3c3e6fe11e896a2c6896412ef6b5c4bcf7e795

Chained

0x23bb4dfd09f55c15ac3962f53578e02c6114d5bfd9bb451cf8794fb6e2817ef4

Published

On Arc Testnet, block 69414147: 0xb2ebd83aafeb765a0ce66e76aefb133ed06606c98038fd56191e2bcd1dcb77b4