{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://councilof.ai/spec/claim-maintenance/v0.1/schema/claim-artifact-v0.1.schema.json",
  "title": "Claim Maintenance artifact, v0.1",
  "description": "One maintained public claim. States are exactly CLAIM_CAPTURED, CLAIM_MEASURED, UNMEASURED, UNCHECKABLE. Nothing in this schema expresses a verdict about a subject, and no mark, score or rank may be derived from any field. Specification: https://councilof.ai/spec/claim-maintenance/v0.1/ (CC0 1.0).",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "schema",
    "claim_id",
    "subject",
    "claim_verbatim",
    "source_url",
    "access_date",
    "source_content_hash",
    "claim_hash",
    "state",
    "does_not_prove",
    "observed_changes",
    "next_read_utc"
  ],
  "properties": {
    "schema": { "const": "csoai.claim-maintenance.artifact/0.1" },
    "claim_id": {
      "type": "string",
      "minLength": 1,
      "description": "Stable within its registry. Never reused for a different claim."
    },
    "subject": {
      "type": "object",
      "additionalProperties": false,
      "required": ["name", "identifier", "identifier_kind"],
      "properties": {
        "name": { "type": "string", "minLength": 1 },
        "identifier": {
          "type": "string",
          "minLength": 1,
          "description": "A stable public identifier. A trading name alone does not identify a subject (spec 5.7)."
        },
        "identifier_kind": {
          "enum": ["url", "domain", "company-register", "lei", "did", "contract-address", "other"]
        },
        "identifier_note": { "type": "string" }
      }
    },
    "claim_verbatim": {
      "type": "string",
      "minLength": 1,
      "description": "The subject's own rendered words. Paraphrase is not capture (spec 5.5)."
    },
    "excerpt": {
      "type": "boolean",
      "description": "True when claim_verbatim is a contiguous excerpt of a longer captured region. Never an edited-together composite."
    },
    "claim_type": { "type": "string" },
    "source_url": { "type": "string", "format": "uri" },
    "access_date": {
      "type": "string",
      "format": "date-time",
      "description": "UTC instant of the read that produced source_content_hash."
    },
    "source_content_hash": {
      "type": "object",
      "additionalProperties": false,
      "required": ["alg", "value", "covers"],
      "properties": {
        "alg": { "const": "sha256" },
        "value": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
        "covers": { "enum": ["visible-text", "raw-bytes", "response-json-canonical"] },
        "extracted_chars": {
          "type": "integer",
          "minimum": 0,
          "description": "Length of the extracted text. Lets a third party tell an extractor difference from a content change (spec 6.3)."
        }
      }
    },
    "claim_hash": {
      "type": "string",
      "pattern": "^[0-9a-f]{64}$",
      "description": "SHA-256 over UTF-8 of claim_verbatim alone (spec 6.2)."
    },
    "state": { "enum": ["CLAIM_CAPTURED", "CLAIM_MEASURED", "UNMEASURED", "UNCHECKABLE"] },
    "measurement_plan": {
      "type": "string",
      "description": "Prose about intent. A plan is not a measurement and must never be presented as one (spec 4.6)."
    },
    "uncheckable_reason": {
      "type": "string",
      "description": "Why no public evidence can settle the claim. A statement about the evidence, never about the subject (spec 4.4)."
    },
    "window": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "required": ["from", "to"],
      "properties": {
        "from": { "type": "string", "format": "date-time" },
        "to": { "type": "string", "format": "date-time" }
      }
    },
    "denominator": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "required": ["description", "n"],
      "properties": {
        "description": { "type": "string" },
        "n": { "type": "integer", "minimum": 0 },
        "source_url": { "type": "string", "format": "uri" },
        "excluded": {
          "type": "array",
          "items": { "type": "string" },
          "description": "Every exclusion, named. An unstated exclusion makes the method irreproducible."
        }
      }
    },
    "method": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "required": ["description", "evidence"],
      "properties": {
        "description": {
          "type": "string",
          "description": "Enough detail that a third party re-running it obtains the same value (spec 4.5)."
        },
        "implementation_url": { "type": "string", "format": "uri" },
        "evidence": {
          "type": "array",
          "minItems": 1,
          "items": {
            "type": "object",
            "additionalProperties": false,
            "required": ["url", "access_date", "content_hash"],
            "properties": {
              "url": { "type": "string", "format": "uri" },
              "access_date": { "type": "string", "format": "date-time" },
              "content_hash": { "type": "string", "pattern": "^[0-9a-f]{64}$" }
            }
          }
        }
      }
    },
    "result": {
      "type": ["object", "null"],
      "additionalProperties": false,
      "required": ["value", "n"],
      "properties": {
        "value": {
          "type": "string",
          "description": "Carried as a string. Floating-point numbers are not reproducible across runtimes (spec 6.1)."
        },
        "unit": { "type": "string" },
        "n": { "type": "integer", "minimum": 0 },
        "unmeasured_of_population": {
          "type": "integer",
          "minimum": 0,
          "description": "Population members the read did not reach. A partial read totalled as a population is a conformance failure (spec 4.6)."
        }
      }
    },
    "does_not_prove": {
      "type": "array",
      "minItems": 1,
      "items": { "type": "string" },
      "description": "What a reader might wrongly conclude. An empty does_not_prove is a malformed artifact (spec 5.4)."
    },
    "observed_changes": {
      "type": "array",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": ["observed_utc", "previous_hash", "current_hash", "note"],
        "properties": {
          "observed_utc": { "type": "string", "format": "date-time" },
          "previous_access_date": { "type": "string", "format": "date-time" },
          "previous_hash": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
          "current_hash": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
          "note": {
            "type": "string",
            "description": "Neutral. Words of motive or concealment are prohibited (spec 4.9). An observed change is never a finding."
          },
          "claim_present": {
            "type": "boolean",
            "description": "Whether claim_verbatim was still present at this read."
          }
        }
      }
    },
    "superseded_measurements": {
      "type": "array",
      "items": {
        "type": "object",
        "additionalProperties": false,
        "required": ["withdrawn_utc", "reason", "artifact_sha256"],
        "properties": {
          "withdrawn_utc": { "type": "string", "format": "date-time" },
          "reason": { "type": "string" },
          "artifact_sha256": { "type": "string", "pattern": "^[0-9a-f]{64}$" }
        }
      }
    },
    "conflicts": {
      "type": "array",
      "items": { "type": "string" },
      "description": "Commercial, membership, investor, employment or standards-body relationship between maintainer and subject. Disclosed at artifact level (spec 10.3)."
    },
    "next_read_utc": { "type": "string", "format": "date-time" },
    "first_captured_utc": { "type": "string", "format": "date-time" },
    "artifact_sha256": {
      "type": "string",
      "pattern": "^[0-9a-f]{64}$",
      "description": "SHA-256 over the canonical bytes of this object without artifact_sha256 and sig (spec 6.4)."
    },
    "sig": {
      "type": "object",
      "additionalProperties": false,
      "required": ["alg", "key_id", "encoding", "value"],
      "properties": {
        "alg": { "const": "Ed25519" },
        "key_id": { "type": "string", "description": "A DID URL, e.g. did:web:example.org#key-1" },
        "encoding": { "enum": ["hex", "base64url"] },
        "value": { "type": "string" }
      }
    }
  },
  "allOf": [
    {
      "if": { "properties": { "state": { "const": "CLAIM_MEASURED" } }, "required": ["state"] },
      "then": { "required": ["window", "method", "result"] }
    },
    {
      "if": { "properties": { "state": { "const": "UNCHECKABLE" } }, "required": ["state"] },
      "then": { "required": ["uncheckable_reason"] }
    },
    {
      "if": {
        "properties": { "state": { "enum": ["CLAIM_CAPTURED", "UNMEASURED"] } },
        "required": ["state"]
      },
      "then": { "required": ["measurement_plan"] }
    }
  ]
}