{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://f-keys.com/ktp/schema/kernel-trust-0.1.schema.json",
  "title": "Kernel Trust Profile 0.1",
  "description": "A machine-readable declaration of what a body of machine-checked mathematics rests on. Every value must be recomputable by a third party from the named revision; null means not measured, and 0 is a positive claim.",
  "type": "object",
  "required": ["ktp_version", "generated_at", "generated_by", "subject", "counts", "unfinished", "compiler_trusted", "assumptions"],
  "additionalProperties": false,
  "properties": {
    "ktp_version": {
      "type": "string",
      "pattern": "^0\\.1$",
      "description": "Specification version. A consumer must not interpret an unknown major version."
    },
    "generated_at": {
      "type": "string",
      "format": "date",
      "pattern": "^[0-9]{4}-[0-9]{2}-[0-9]{2}$"
    },
    "generated_by": {
      "type": "object",
      "required": ["tool", "version"],
      "additionalProperties": false,
      "properties": {
        "tool": { "type": "string", "minLength": 1 },
        "version": { "type": "string", "minLength": 1 },
        "url": { "type": ["string", "null"], "format": "uri" }
      }
    },
    "subject": {
      "type": "object",
      "required": ["name", "system"],
      "additionalProperties": false,
      "properties": {
        "name": { "type": "string", "minLength": 1 },
        "system": { "type": "string", "minLength": 1, "examples": ["Lean 4", "Metamath", "Coq", "Isabelle"] },
        "system_version": { "type": ["string", "null"] },
        "revision": {
          "type": ["string", "null"],
          "description": "Commit hash or released version. Required in practice for the profile to be recomputable."
        },
        "foundation": { "type": ["string", "null"], "examples": ["ZFC", "dependent type theory", "intuitionistic"] },
        "url": { "type": ["string", "null"], "format": "uri" }
      }
    },
    "counts": {
      "type": "object",
      "required": ["theorems"],
      "additionalProperties": false,
      "properties": {
        "theorems": {
          "type": "integer",
          "minimum": 0,
          "description": "Denominator for every reported fraction."
        },
        "declarations": { "type": ["integer", "null"], "minimum": 0 }
      }
    },
    "unfinished": { "$ref": "#/$defs/hatch" },
    "compiler_trusted": { "$ref": "#/$defs/hatch" },
    "assumptions": {
      "type": "array",
      "items": {
        "type": "object",
        "required": ["name", "kind", "reach"],
        "additionalProperties": false,
        "properties": {
          "name": { "type": "string", "minLength": 1 },
          "kind": {
            "enum": ["foundational", "optional", "escape-hatch"],
            "description": "foundational: the system's own basis. optional: removable in principle. escape-hatch: unfinished or compiler-trusting."
          },
          "entry_points": {
            "type": ["integer", "null"],
            "minimum": 0,
            "description": "Declarations whose own proof cites this, as opposed to inheriting it. null means not computed."
          },
          "reach": {
            "type": "object",
            "required": ["theorems"],
            "additionalProperties": false,
            "properties": {
              "theorems": { "type": "integer", "minimum": 0 },
              "fraction": { "type": ["number", "null"], "minimum": 0, "maximum": 1 }
            }
          },
          "via": {
            "enum": ["statement", "proof", "both", null],
            "description": "Whether the dependency enters through the theorem statement, only its proof, or both. Collapsing these discards what makes the measurement actionable."
          },
          "amplification": {
            "type": ["number", "null"],
            "minimum": 0,
            "description": "Dependents per entry point. Reportable, but not comparable between libraries: factoring a shared step into a lemma changes it without changing what is proved."
          }
        }
      }
    }
  },
  "$defs": {
    "hatch": {
      "type": "object",
      "required": ["theorems_reaching"],
      "additionalProperties": false,
      "properties": {
        "theorems_reaching": {
          "type": ["integer", "null"],
          "minimum": 0,
          "description": "Theorems reaching this from anywhere upstream. null means not measured; 0 is a positive claim that must be backed by a measurement."
        },
        "axioms": {
          "type": "array",
          "items": { "type": "string" },
          "description": "The axiom names that signal it in this system."
        }
      }
    }
  }
}