Evidence row 307847

What was observed

{
  "count": 11,
  "tools": [
    {
      "description": "Coverage blind spots: companies, models, and people that regional press (Chinese/East-Asian, European, Latin-American) is covering while Western/global feeds are not — ranked, with per-region item counts. Answers \"what is Western tech media missing right now?\". Measured within Horizon's corpus: \"invisible\" means zero pickup in the Western feeds Horizon tracks, not a claim about all media.",
      "inputSchema": {
        "properties": {
          "days": {
            "description": "Lookback window in days (default 60, 7–180).",
            "type": "number"
          },
          "limit": {
            "description": "Max entities (default 15, cap 50).",
            "type": "number"
          }
        },
        "type": "object"
      },
      "name": "get_blind_spots"
    },
    {
      "description": "Shortcut for get_region_signal with region \"china\": the current China & East-Asia AI signal (Qwen, DeepSeek, Zhipu, Moonshot, ModelScope, and more) that Western feeds often miss — ranked by momentum. Prefer get_region_signal if you may query more than one region.",
      "inputSchema": {
        "properties": {
          "limit": {
            "description": "Max items (default 15, cap 40).",
            "type": "number"
          }
        },
        "type": "object"
      },
      "name": "get_china_signal"
    },
    {
      "description": "Today's AI briefing, or any past day's: top stories with their sources and corroboration labels, emerging signals, new entrants, and regulation updates. Drawn from Hacker News, Reddit, Bluesky, arXiv, Hugging Face, lab blogs, tech press in the US, Europe and East Asia, and legislative sources. A curated once-daily synthesis — for raw item-level updates since your last check, use get_new_since instead. Pass a date (YYYY-MM-DD) for a past day; set top_stories_only for a shorter result.",
      "inputSchema": {
        "properties": {
          "date": {
            "description": "Optional YYYY-MM-DD for a past briefing (any date in the archive); omit for the latest briefing.",
            "type": "string"
          },
          "top_stories_only": {
            "description": "Optional. True returns only the top stories with their sources, leaving out signals, new entrants, movers, regional highlights and regulation. Omit for the whole briefing.",
            "type": "boolean"
          }
        },
        "type": "object"
      },
      "name": "get_daily_briefing"
    },
    {
      "description": "For one company, model, or person: how much of the claim activity Horizon holds provenance data for is self-reported by that entity versus independently evaluated by someone else. Descriptive counts over the last 30 days — not a score, and not a judgement about whether any claim is true. Answers \"is the buzz around X coming from X?\".",
      "inputSchema": {
        "properties": {
          "entity": {
            "description": "Entity name, e.g. 'Qwen 3.8' or 'Anthropic'.",
            "type": "string"
          }
        },
        "required": [
          "entity"
        ],
        "type": "object"
      },
      "name": "get_entity_provenance"
    },
    {
      "description": "Incremental poll: raw item-level AI news added since a cursor, oldest→newest, with a nextCursor for your next call — use this for \"what's new since I last checked\"; for the curated once-daily synthesis use get_daily_briefing. Omit cursor for the latest items plus a cursor to start polling from. Returns titles, links and topics.",
      "inputSchema": {
        "properties": {
          "cursor": {
            "description": "Opaque cursor from a previous call's nextCursor. Omit on the first call.",
            "type": "string"
          },
          "limit": {
            "description": "Max items (default 25, cap 50).",
            "type": "number"
          }
        },
        "type": "object"
      },
      "name": "get_new_since"
    },
    {
      "description": "The current AI signal for a region (china, korea, japan, or eu) — recent, relevance-scored items on that region's models, labs, and analysis, ranked by momentum. Includes local-language press translated into English. The canonical regional tool; get_china_signal is a preset of this with region \"china\". Returns titles, sources, and links.",
      "inputSchema": {
        "properties": {
          "limit": {
            "description": "Max items (default 15, cap 40).",
            "type": "number"
          },
          "region": {
            "description": "Region slug (china, korea, japan, eu).",
            "enum": [
              "china",
              "korea",
              "japan",
              "eu"
            ],
            "type": "string"
          }
        },
        "required": [
          "region"
        ],
        "type": "object"
      },
      "name": "get_region_signal"
    },
    {
      "description": "Current AI legislation headlines across the US Congress and federal agencies, US state legislatures, the UK Parliament, and the EU, with each item's legislative stage (proposed / committee / floor action / passed / implementation). State bills are the largest share by far; filter with jurisdiction to narrow.",
      "inputSchema": {
        "properties": {
          "jurisdiction": {
            "description": "Optional filter to one jurisdiction.",
            "enum": [
              "us_federal",
              "us_state",
              "uk",
              "eu"
            ],
            "type": "string"
          },
          "limit": {
            "description": "Max headlines (default 50, cap 100).",
            "type": "number"
          }
        },
        "type": "object"
      },
      "name": "get_regulation_updates"
    },
    {
      "description": "Semantic 'more like this': given an item id (from get_new_since, search_news, or the feed), returns the most similar recent items by embedding similarity. Titles, sources, similarity scores, links.",
      "inputSchema": {
        "properties": {
          "id": {
            "description": "UUID of an item from a previous result.",
            "type": "string"
          },
          "limit": {
            "description": "Max related items (default 10, cap 25).",
            "type": "number"
          }
        },
        "required": [
          "id"
        ],
        "type": "object"
      },
      "name": "get_related"
    },
    {
      "description": "The current AI signal for a topic — recent, relevance-scored items tagged with that topic, ranked by momentum. Like get_region_signal but sliced by subject instead of geography.",
      "inputSchema": {
        "properties": {
          "limit": {
            "description": "Max items (default 15, cap 40).",
            "type": "number"
          },
          "topic": {
            "description": "Topic slug.",
            "enum": [
              "models",
              "tools",
              "use-cases",
              "regulation",
              "research",
              "funding",
              "opinion",
              "tutorial"
            ],
            "type": "string"
          }
        },
        "required": [
          "topic"
        ],
        "type": "object"
      },
      "name": "get_topic_signal"
    },
    {
      "description": "Describe what Horizon covers: ingestion sources with their source= filter values, the regional lenses (region= / dedicated tools), and how to filter. Call this to understand the corpus before querying.",
      "inputSchema": {
        "properties": {},
        "type": "object"
      },
      "name": "list_sources"
    },
    {
      "description": "Quick title search over the last 14 days of AI news: returns the top 3 matches by momentum, with links and item ids (pass one to get_related).",
      "inputSchema": {
        "properties": {
          "query": {
            "description": "Search terms.",
            "type": "string"
          }
        },
        "required": [
          "query"
        ],
        "type": "object"
      },
      "name": "search_news"
    }
  ]
}

What the leaf hashes

{"body":"40e34d01ffd669f5b48e65365d482733f9ed71c882ba42354e4a4326e2d9ca73","id":307847,"kind":"mcp.tools","method":"probe.mcp/1","observed_us":1793057925128431,"prev":null,"subject":"4ad72a37-dc57-4331-9a8b-6e711303e023","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. 0x3c5c37653c3fab00fe3f0952bd14e1bdaadfcaca873ffbdc40dd5fb436f3e068
2. 0x2cb479b76836117db117cb0342e08821f1f76560dbef8abbf53d5e1b0b1cb638
3. 0x4ae1ab43959acef66393f3b712096766b9fd791bf8858d15c4bb6fbfee69c1fe
4. 0xd11b25b3a7eeb4c1063d828a3fdda2f49654b8d5444a1e35d891bf204d7fbd7a
5. 0x8fddb03bd77919c3dc315954277189162aa701b1705794b92d28932c4e2d3cb5
6. 0x6693773c3b3d85206bdcddd3dd5c684331659565fed2ad73e15fd18f6dc98a72
7. 0x88e1219f5d875b325ef5862483188bd23a67ecfb198abd5a5f0dca2f9c7ce395
8. 0x80d479552012f6e936eed072d101dc52e1a752572cfb197539a94b42817516d8
9. 0xf3377e5a3d9ffa09ca4a8f90e033745dad5af466386e85882a894e4c3fbfb0f4
10. 0x210e4fd4b2b60dbd88a7f42093d3d642e105b1738155bf382034c694bee5fbcf
11. 0xd7dd18a37a5bb07e81a8083d8d1469e052ceebb2814b00f5a8d4f4cd181a5108
12. 0xd04df0f7f3be4d014b4cea8172ada286fbcf5bcb32ae1b281704fd75627b661b
13. 0x215f432600b78f2e7c9629cd10ce6ce4b7f3351b0b71f3f2c7dcb8e650f6cd63
14. 0x7f594f5609f388d64d3cda87b5631d393ee8300bb09bad71f150113a5886ee33
15. 0x4b52a97f7a80ff7778a702b85267b8d2e5c93ce160942656435c29ae7be68bf4
16. 0x2e6a32eb32761c210560e852405e2f865f958ddbe01027894f8b9c1b3433b9f0
17. 0x9a83be955a206deb65b995adfd92c58fa31c95fbbf926bd199d300e70b08b26d
18. 0x20704208aa6923d6b2450ef74ede87a6e0265d46447926038fe9506e9e154b2d
19. 0x9b9ce5b74b9bab5121612ef6b64920a8d453cbf311096a423eef9702747e868a

Day root

0xf43e8dcc3d451a4788b26be904c55e8c4c0fa75c9666796c51db38d37e2c0df8

Chained

0x702d5ac508f08b0d1accf36af25822d8e5660367494edd17a642fb61e158a57a

Published

On Arc Testnet, block 69251483: 0x495162f8936e19f0039918feebe6c307f327cd6bf8c37219620b1970041fa9ae