{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-12T01:28:50Z",
    "providers": [
      "Claude"
    ],
    "breadth": "written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify",
    "pass": 2,
    "wave": 2,
    "engine": "claude",
    "enrichment": {
      "pass": 3,
      "engine": "claude",
      "producedAt": "2026-10-05T23:55:00Z",
      "ingestedAt": "2026-10-05T20:54:52+00:00",
      "fields": [
        "agent_conduct",
        "ethics",
        "owners"
      ]
    },
    "gate": {
      "passed": true,
      "version": "1.0",
      "at": "2026-10-06T19:51:57+00:00",
      "evidence": [
        "completeness 1.00",
        "sense: Wikidata description",
        "2 live sources",
        "review by codex: pass"
      ]
    }
  },
  "metaModel": {
    "id": "THING-Q2521",
    "registryId": "vr.tr.april-18",
    "name": "April 18",
    "version": "0.2.0-wave.2",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "XCT.TME"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q2521/",
  "model": {
    "registry_id": "vr.tr.april-18",
    "name": "April 18",
    "purpose": "Let an agent handle April 18 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.",
    "definition": "April 18, day 108 (day 109 in leap years) of the year in the Gregorian calendar, with 257 days remaining in both common and leap years. Observances on this date vary by country and tradition; it is the International Day for Monuments and Sites.",
    "what_it_is_for": "A calendar date for scheduling, holidays and anniversaries.",
    "affordances": [
      "compute its weekday in a given year",
      "check local and international observances",
      "find sourced historical events",
      "schedule events"
    ],
    "distinguishing_features": [
      "The eighteenth day of April",
      "Weekday varies by year",
      "Observances vary by place",
      "Julian and Gregorian dates differ by 13 days in this era"
    ],
    "appearance": "A date on calendars.",
    "visual_identification": [
      "Written 18 April or April 18",
      "ISO format --04-18",
      "Observances vary by country and tradition"
    ],
    "physical_properties": [
      {
        "quantity": "day of year",
        "typical_range": "108 or 109",
        "unit": "day",
        "note": "common year, leap year where different"
      },
      {
        "quantity": "days remaining",
        "typical_range": "257",
        "unit": "days",
        "note": ""
      }
    ],
    "families_and_kinds": [
      "the recurring calendar date",
      "specific dated days in given years"
    ],
    "related_models": [
      {
        "relation": "is part of",
        "target": "April",
        "why": "month"
      },
      {
        "relation": "follows",
        "target": "April 17",
        "why": "date"
      },
      {
        "relation": "is a kind of",
        "target": "calendar date",
        "why": "category"
      },
      {
        "relation": "is expressed in",
        "target": "ISO 8601",
        "why": "notation"
      }
    ],
    "identifiers": [
      {
        "scheme": "ISO 8601",
        "value_or_pattern": "--04-18",
        "note": "recurring date"
      }
    ],
    "standards_and_regulation": [
      "ISO 8601",
      "National public holiday laws"
    ],
    "failure_modes_and_hazards": [
      "Assuming observances are universal",
      "Unsourced on-this-day events",
      "Mixing Julian and Gregorian dates"
    ],
    "in_scope": [],
    "out_of_scope": [],
    "characteristics": [],
    "agent_conduct": {
      "may": [
        "Convert April 18 between calendars and give its day number in common and leap years.",
        "Describe the International Day for Monuments and Sites and its heritage aims.",
        "List other observances with the country or community that keeps each."
      ],
      "must_not": [
        "Present an event as having happened on April 18 without a source.",
        "Treat a local observance as universal.",
        "Use the heritage day to promote visits that damage fragile sites.",
        "Mix Julian and Gregorian dates for older events without saying so."
      ],
      "requires_human": [
        "Publishing anniversary content about deaths or disasters on this date."
      ]
    },
    "ethics": {
      "considerations": [
        "Heritage awareness days carry the interests of communities whose sites are at risk.",
        "Unsourced on-this-day claims spread false history."
      ],
      "affected_parties": [
        "Heritage communities",
        "Readers of anniversary lists"
      ]
    },
    "owners": {
      "steward": "The public: held in common; the Gregorian calendar is a shared convention.",
      "master_systems": []
    }
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q2521: April 18",
      "url": "https://www.wikidata.org/wiki/Q2521",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: April 18",
      "url": "https://en.wikipedia.org/wiki/April_18",
      "url_status": "live",
      "what_it_supports": "general description of the item",
      "checked_by": "wikidata-api sitelink"
    }
  ],
  "structure": {
    "bundles": [
      {
        "id": "date",
        "name": "Date",
        "description": "Calendar facts.",
        "rationale": "Calendar arithmetic.",
        "layers": [
          {
            "id": "weekday",
            "name": "Weekday",
            "description": "Computation.",
            "findings": [
              {
                "id": "weekday-finding",
                "name": "Weekday",
                "description": "Weekday.",
                "questions": [
                  {
                    "text": "On which weekday does April 18 fall in this year?",
                    "kind": "measurement"
                  },
                  {
                    "text": "Is it a leap year?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          },
          {
            "id": "calendar",
            "name": "Calendar",
            "description": "Julian or Gregorian.",
            "findings": [
              {
                "id": "calendar-finding",
                "name": "Calendar",
                "description": "Calendar system.",
                "questions": [
                  {
                    "text": "Is the Julian or Gregorian calendar meant?",
                    "kind": "boundary"
                  },
                  {
                    "text": "What is the equivalent date in the other calendar?",
                    "kind": "measurement"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "observances",
        "name": "Observances",
        "description": "Holidays.",
        "rationale": "Observances vary.",
        "layers": [
          {
            "id": "holiday",
            "name": "Holiday",
            "description": "Public holiday.",
            "findings": [
              {
                "id": "holiday-finding",
                "name": "Holiday",
                "description": "Holiday status.",
                "questions": [
                  {
                    "text": "Is April 18 a public holiday or observance here?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which tradition or law sets it?",
                    "kind": "provenance"
                  }
                ]
              }
            ]
          },
          {
            "id": "attribution",
            "name": "Attribution",
            "description": "Traditions.",
            "findings": [
              {
                "id": "attribution-finding",
                "name": "Attribution",
                "description": "Attributed observances.",
                "questions": [
                  {
                    "text": "Which countries or communities observe something on this date, according to them?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Is the observance attributed rather than assumed?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "history",
        "name": "History",
        "description": "Past events.",
        "rationale": "Events need sources.",
        "layers": [
          {
            "id": "events",
            "name": "Events",
            "description": "On this day.",
            "findings": [
              {
                "id": "events-finding",
                "name": "Events",
                "description": "Historical events.",
                "questions": [
                  {
                    "text": "Which notable events happened on April 18, according to reliable sources?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Are dates given in the same calendar?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          },
          {
            "id": "anniversaries",
            "name": "Anniversaries",
            "description": "Recurring.",
            "findings": [
              {
                "id": "anniversaries-finding",
                "name": "Anniversaries",
                "description": "Anniversaries.",
                "questions": [
                  {
                    "text": "Which anniversaries fall on this date this year?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Which are round numbers?",
                    "kind": "measurement"
                  }
                ]
              }
            ]
          }
        ]
      },
      {
        "id": "planning",
        "name": "Planning",
        "description": "Scheduling.",
        "rationale": "Dates drive plans.",
        "layers": [
          {
            "id": "countdown",
            "name": "Countdown",
            "description": "Days until.",
            "findings": [
              {
                "id": "countdown-finding",
                "name": "Countdown",
                "description": "Countdown.",
                "questions": [
                  {
                    "text": "How many days until the next April 18?",
                    "kind": "measurement"
                  },
                  {
                    "text": "From which date?",
                    "kind": "definition"
                  }
                ]
              }
            ]
          },
          {
            "id": "work",
            "name": "Work",
            "description": "Working day.",
            "findings": [
              {
                "id": "work-finding",
                "name": "Work",
                "description": "Working day.",
                "questions": [
                  {
                    "text": "Is it a working day for this organisation?",
                    "kind": "provenance"
                  },
                  {
                    "text": "Do deadlines move?",
                    "kind": "boundary"
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  },
  "openQuestions": [
    "Should dated days be separate entries?",
    "How should observances be linked?",
    "How should events be sourced?"
  ],
  "statistics": {
    "bundles": 4,
    "layers": 8,
    "findings": 8,
    "questions": 16
  }
}