{
  "vercy": "1.0-draft",
  "publication": {
    "status": "research-draft",
    "adjudicationStatus": "unreviewed",
    "publishableCanonical": false,
    "generatedAt": "2026-09-12T00:17:05Z",
    "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": "2026-10-05T23:50:00Z",
      "ingestedAt": "2026-10-05T20:47:05+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-Q2525",
    "registryId": "vr.tr.april-21",
    "name": "April 21",
    "version": "0.2.0-wave.2",
    "entryKind": "thing",
    "family": "Thing Registry",
    "domain": [
      "XCT.TME"
    ],
    "status": "research-draft"
  },
  "canonicalUrl": "https://ver.cy/models/thing/q2525/",
  "model": {
    "registry_id": "vr.tr.april-21",
    "name": "April 21",
    "purpose": "Let an agent handle April 21 as a calendar date with weekday computation, observances attributed to their traditions and sourced events.",
    "definition": "April 21, day 111 (day 112 in leap years) of the year in the Gregorian calendar, with 254 days remaining in both common and leap years. Observances on this date vary by country and tradition.",
    "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 twenty-first 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 21 April or April 21",
      "ISO format --04-21",
      "Observances vary by country and tradition"
    ],
    "physical_properties": [
      {
        "quantity": "day of year",
        "typical_range": "111 or 112",
        "unit": "day",
        "note": "common year, leap year where different"
      },
      {
        "quantity": "days remaining",
        "typical_range": "254",
        "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 20",
        "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": "--04-21",
        "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": [
        "Compute day-of-year and weekday for April 21 in a given year.",
        "List events and observances on April 21 by country with sources."
      ],
      "must_not": [
        "Report anniversaries for April 21 without a source.",
        "Present one country's April 21 holiday as observed everywhere.",
        "Convert historical April 21 dates between calendars without saying so."
      ],
      "requires_human": [
        "Fixing a legal deadline that falls on an April 21 public holiday."
      ]
    },
    "ethics": {
      "considerations": [
        "False on-this-day claims spread quickly and attach to real people and events."
      ],
      "affected_parties": [
        "Calendar users",
        "People named in anniversaries"
      ]
    },
    "owners": {
      "steward": "Nobody owns a date; calendar and holiday authorities set observances.",
      "master_systems": []
    }
  },
  "sources": [
    {
      "id": "wikidata",
      "title": "Wikidata item Q2525: April 21",
      "url": "https://www.wikidata.org/wiki/Q2525",
      "url_status": "live",
      "what_it_supports": "identity and sense of the item",
      "checked_by": "wikidata-api"
    },
    {
      "id": "wikipedia-en",
      "title": "Wikipedia: April 21",
      "url": "https://en.wikipedia.org/wiki/April_21",
      "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 21 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 21 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 21, 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 21?",
                    "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
  }
}