{
  "protocol": {
    "name": "CVP",
    "version": "1.0.0-proposed",
    "revision": "2026-09-13",
    "spec_sha256": "f62725968356c92930531cd6085db76e216da06e95be53d636b0d2cf3218b148",
    "spec": "https://www.calculatorx.com/developers/cvp/spec/1.0"
  },
  "document_status": "proposed",
  "calculator": {
    "id": "fractions",
    "version": "1.0.6",
    "title": "Fractions Calculator",
    "formula_family": "fractions",
    "capability_id": "math.fractions",
    "verification_revision": "2026-09-30.safe-integer-scope"
  },
  "profile": "core",
  "verified_scope": "operate (+/−/×/÷) and simplify",
  "status": "STALE",
  "verification_status": "VERIFIED",
  "production_freshness": "STALE",
  "overall_trust": "VERIFIED_STALE",
  "runner": {
    "name": "cvp-runner",
    "version": "1.0.0"
  },
  "environment": {
    "runtime": "node",
    "runtime_version": "20.19.2",
    "numeric_model": "IEEE-754 binary64",
    "os": "darwin"
  },
  "suite": {
    "id": "fractions",
    "version": "1.0.6",
    "uri": "https://www.calculatorx.com/evidence/math.fractions/1.0.6.json",
    "verification_revision": "2026-09-30.safe-integer-scope"
  },
  "obligation_set": [
    "CVP-PROV-01",
    "CVP-MODEL-01",
    "CVP-SCOPE-01",
    "CVP-UNIT-01",
    "CVP-REF-01",
    "CVP-GOLD-01",
    "CVP-BND-01",
    "CVP-INV-01",
    "CVP-NUM-01",
    "CVP-COV-01",
    "CVP-CONTRACT-01",
    "CVP-DEP-01",
    "CVP-ART-01",
    "CVP-PROD-01",
    "CVP-PROP-01",
    "CVP-META-01",
    "CVP-ROUND-01",
    "CVP-IFACE-01"
  ],
  "provenance": {
    "mode": "direct",
    "sources": [
      {
        "label": "OpenStax — Prealgebra 2e",
        "kind": "other",
        "reference": "4.5 Add and Subtract Fractions with Different Denominators",
        "url": "https://openstax.org/books/prealgebra-2e/pages/4-5-add-and-subtract-fractions-with-different-denominators"
      },
      {
        "label": "OpenStax — Prealgebra 2e",
        "kind": "other",
        "reference": "4.2 Multiply and Divide Fractions",
        "url": "https://openstax.org/books/prealgebra-2e/pages/4-2-multiply-and-divide-fractions"
      },
      {
        "label": "OpenStax — Prealgebra 2e",
        "kind": "other",
        "reference": "4.3 Multiply and Divide Mixed Numbers and Complex Fractions",
        "url": "https://openstax.org/books/prealgebra-2e/pages/4-3-multiply-and-divide-mixed-numbers-and-complex-fractions"
      }
    ]
  },
  "reference": {
    "items": [
      {
        "class": "O1",
        "reference_scope": "model",
        "scope": "model",
        "label": "Fraction arithmetic with LCD reduction"
      },
      {
        "class": "O2",
        "reference_scope": "expected_values",
        "scope": "expected_values",
        "label": "Separate-module fractions oracle — independent BigInt LCD / product arithmetic",
        "engine": {
          "name": "fractions-reference",
          "independent_of_iut": true
        }
      },
      {
        "class": "O2",
        "reference_scope": "numerical_behavior",
        "scope": "numerical_behavior",
        "label": "Same BigInt O2 module backs exact n/d comparison vs IUT",
        "engine": {
          "name": "fractions-reference",
          "independent_of_iut": true
        }
      }
    ],
    "notes": "Golden expected values use a separate O2 module (not IUT transcription). O2 shares Node/V8 binary64 with the IUT unless noted otherwise."
  },
  "controls": {
    "CVP-PROV-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "Sources present on evidence"
    },
    "CVP-MODEL-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "LCD add/sub; product; reciprocal divide"
    },
    "CVP-SCOPE-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "O2 BigInt gold covers operate (+/−/×/÷) and simplify only. Fraction integer inputs and every arithmetic intermediate must be safe integers (|x| ≤ 2^53−1); overflow returns VALUE_OUT_OF_RANGE. to-dec and from-dec have engine regression coverage, not O2 mode verification."
    },
    "CVP-UNIT-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "dimensionless rational"
    },
    "CVP-REF-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "O1 model + O2 expected_values + O2 numerical_behavior"
    },
    "CVP-GOLD-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "20/20 legacy golden; 6/6 oracle-backed numeric"
    },
    "CVP-BND-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "8/8 CVP boundary · 8/8 legacy Evidence boundary"
    },
    "CVP-INV-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "6 Evidence illegal-input + 2/2 oracle-backed error-code (exact_error_match, not ULP)"
    },
    "CVP-NUM-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "max_error_observed_ulp=0; policy declared a priori"
    },
    "CVP-COV-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "6/6 declared partitions (operate:add, operate:subtract, operate:multiply, operate:divide, simplify, invalid-domain) · 20 legacy golden / 8 CVP boundary unique cases · 6 Evidence invalid-input (may overlap boundary)"
    },
    "CVP-CONTRACT-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "5/5 CVP contract · release-artifacts-aligned=PASS · schema-output-required-declared=PASS · schema-valid-input-executes=PASS · engine-success-output-validates-schema=PASS · rest-success-payload-validates-schema=PASS"
    },
    "CVP-DEP-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "engine fractions; Node binary64"
    },
    "CVP-ART-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "release_integrity.status=verified · digests: artifact_evidence_sha256=Evidence core (Trust freshness) · cvp_evidence_digest=artifacts.evidence_digest (fingerprint v2) · evidence_bundle_sha256=legacy Evidence JSON bytes · evidence_catalog_digest=attested_catalog_sha256 · production_sha256=bound production report · see artifacts.digest_registry"
    },
    "CVP-PROD-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "Capability production binding: STALE · Site report: stale · STALE (freshness / digest drift after last PASS snapshot) · site report stale · local checks pass · local production checks PASS; capability production binding is not CURRENT — final status must stay STALE, not VERIFIED · attestation_id=b6db86a3946922a6529492107ca8043828115b3ffd21d9c4669ff69fb7f854ce · Capability production binding: STALE · Site report: STALE · Public schema 1.0.6 observed · production binding STALE · Semantic contract ✓ · Last attestation PASS · Evidence changed after the last successful production attestation. Re-attestation required. · Public/cache ✓ · Origin ✓ · schema_const=1.0.6 · report output-const=pass · evidence-sha256=pass · semantic-contract=pass · capability-html-public-origin-agree=pass · cvp-manifest-public-origin-agree=pass · cvp-latest-alias-agrees=pass · calculator-html-cvp-projection=pass · evidence-html-cvp-projection=pass · attested_evidence_sha256=8a224dbdcd21223942d0e73df9a3c58e3b2c63d744bd5164790a86cc92da0fc9 · verified_at=2026-09-30T13:14:02.480Z · evidence_attested_at=2026-09-30T13:14:02.480Z · last_confirmed_current_at=2026-09-30T13:14:02.480Z · rendered_at=2026-09-30T13:41:27.655Z · binds=cvp_core_sha256 · Capability production binding: STALE · Site report: STALE · Evidence changed after the last successful production attestation. Re-attestation required.",
      "check_result": "PASS",
      "production_state": "STALE",
      "binding_current": false
    },
    "CVP-DIM-01": {
      "result": "SKIP",
      "applicability": "not_applicable",
      "notes": "Unitless core calculator — no physical dimension algebra"
    },
    "CVP-PROP-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "2/2 property"
    },
    "CVP-META-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "1/1 metamorphic"
    },
    "CVP-ROUND-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "1/1 round-trips"
    },
    "CVP-XCAL-01": {
      "result": "SKIP",
      "applicability": "not_applicable",
      "notes": "No related calculator in the same formula family / no related-identity peers declared — control not in obligation set"
    },
    "CVP-IFACE-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "UI (SSR) · REST · MCP equivalent (MCP uses calc API handler). ui-ssr is query-result HTML, not a live browser session."
    },
    "CVP-ORACLE-01": {
      "result": "SKIP",
      "applicability": "higher_assurance",
      "notes": "O2 present; O3 not required this wave"
    },
    "CVP-EXP-01": {
      "result": "SKIP",
      "applicability": "optional",
      "notes": "named expert review not performed"
    }
  },
  "tests": {
    "golden": {
      "passed": 6,
      "total": 6,
      "failed": 0,
      "case_ids": [
        "g-add",
        "g-subtract",
        "g-multiply",
        "g-divide",
        "g-simplify",
        "g-safe-limit"
      ]
    },
    "boundary": {
      "passed": 8,
      "total": 8,
      "failed": 0,
      "case_ids": [
        "boundary-den-zero-a",
        "boundary-den-zero-b",
        "boundary-div-zero",
        "boundary-missing",
        "boundary-invalid-num",
        "boundary-from-dec-empty",
        "boundary-alias-add",
        "boundary-from-neg-decimal"
      ]
    },
    "invalid": {
      "passed": 8,
      "total": 8,
      "failed": 0,
      "case_ids": [
        "boundary-den-zero-a",
        "boundary-den-zero-b",
        "boundary-div-zero",
        "boundary-missing",
        "boundary-invalid-num",
        "boundary-from-dec-empty",
        "invalid-add-overflow",
        "invalid-lcm-overflow"
      ],
      "comparison": "exact_error_match",
      "records": [
        {
          "id": "invalid-add-overflow",
          "comparison": "exact_error_match",
          "expected": {
            "code": "VALUE_OUT_OF_RANGE"
          },
          "actual": {
            "code": "VALUE_OUT_OF_RANGE"
          },
          "match": true
        },
        {
          "id": "invalid-lcm-overflow",
          "comparison": "exact_error_match",
          "expected": {
            "code": "VALUE_OUT_OF_RANGE"
          },
          "actual": {
            "code": "VALUE_OUT_OF_RANGE"
          },
          "match": true
        }
      ]
    },
    "property": {
      "passed": 2,
      "total": 2,
      "failed": 0,
      "case_ids": [
        "prop-add-zero",
        "prop-mul-one"
      ],
      "definition_ids": [
        "add-zero",
        "mul-one"
      ]
    },
    "round_trip": {
      "passed": 1,
      "total": 1,
      "failed": 0,
      "case_ids": [
        "rt-add-sub"
      ]
    },
    "metamorphic": {
      "passed": 1,
      "total": 1,
      "failed": 0,
      "case_ids": [
        "meta-commute-add"
      ],
      "definition_ids": [
        "commutative-add"
      ]
    },
    "contract": {
      "passed": 5,
      "total": 5,
      "failed": 0
    },
    "cross_interface": {
      "passed": 7,
      "total": 7,
      "failed": 0,
      "case_ids": [
        "iface-add",
        "iface-subtract",
        "iface-multiply",
        "iface-divide",
        "iface-simplify",
        "iface-to-dec",
        "iface-from-dec"
      ]
    }
  },
  "coverage": {
    "partitions": [
      {
        "id": "operate:add",
        "description": "Operate +",
        "exercised": true,
        "case_count": 10
      },
      {
        "id": "operate:subtract",
        "description": "Operate -",
        "exercised": true,
        "case_count": 2
      },
      {
        "id": "operate:multiply",
        "description": "Operate *",
        "exercised": true,
        "case_count": 5
      },
      {
        "id": "operate:divide",
        "description": "Operate /",
        "exercised": true,
        "case_count": 2
      },
      {
        "id": "simplify",
        "description": "Simplify",
        "exercised": true,
        "case_count": 8
      },
      {
        "id": "invalid-domain",
        "description": "Invalid inputs",
        "exercised": true,
        "case_count": 8
      }
    ]
  },
  "numerical": {
    "representation": "exact integer rational within the published safe-integer envelope",
    "tolerance": {
      "type": "absolute",
      "value": 0,
      "rationale": "Independent BigInt rational ops; exact improper match vs IUT within its safe-integer envelope. Declared a priori.",
      "declared_before_evaluation": true
    },
    "max_error_observed": 0,
    "records": [
      {
        "id": "g-add",
        "reference": {
          "mode": "operate",
          "op": "+",
          "n": 11,
          "d": 12,
          "improper": "11/12"
        },
        "actual": {
          "mode": "operate",
          "op": "+",
          "n": 11,
          "d": 12,
          "improper": "11/12",
          "mixed": "11/12",
          "display": "11/12",
          "decimal": "0.916666666667",
          "decimal_display": "0.916666666667",
          "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
          "steps": [
            "3/4 + 1/6",
            "LCD = LCM(4, 6) = 12",
            "3/4 = 9/12",
            "1/6 = 2/12",
            "9/12 + 2/12 = 11/12",
            "GCF(11, 12) = 1",
            "11/12 is already in lowest terms.",
            "Decimal: 11 ÷ 12 ≈ 0.916666666667"
          ],
          "explainer": "3/4 + 1/6 = 11/12 ≈ 0.916666666667.",
          "inputs_label": "3/4 + 1/6",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "g-subtract",
        "reference": {
          "mode": "operate",
          "op": "-",
          "n": 7,
          "d": 12,
          "improper": "7/12"
        },
        "actual": {
          "mode": "operate",
          "op": "-",
          "n": 7,
          "d": 12,
          "improper": "7/12",
          "mixed": "7/12",
          "display": "7/12",
          "decimal": "0.583333333333",
          "decimal_display": "0.583333333333",
          "formula": "L = LCM(b, d); a/b − c/d = [a(L/b) − c(L/d)] / L",
          "steps": [
            "3/4 − 1/6",
            "LCD = LCM(4, 6) = 12",
            "3/4 = 9/12",
            "1/6 = 2/12",
            "9/12 − 2/12 = 7/12",
            "GCF(7, 12) = 1",
            "7/12 is already in lowest terms.",
            "Decimal: 7 ÷ 12 ≈ 0.583333333333"
          ],
          "explainer": "3/4 − 1/6 = 7/12 ≈ 0.583333333333.",
          "inputs_label": "3/4 − 1/6",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "g-multiply",
        "reference": {
          "mode": "operate",
          "op": "*",
          "n": 1,
          "d": 8,
          "improper": "1/8"
        },
        "actual": {
          "mode": "operate",
          "op": "*",
          "n": 1,
          "d": 8,
          "improper": "1/8",
          "mixed": "1/8",
          "display": "1/8",
          "decimal": "0.125",
          "decimal_display": "0.125",
          "formula": "a/b × c/d = ac / bd",
          "steps": [
            "3/4 × 1/6",
            "Multiply: (3×1) / (4×6) = 3/24",
            "GCF(3, 24) = 3",
            "Reduced result: 1/8",
            "Decimal: 1 ÷ 8 ≈ 0.125"
          ],
          "explainer": "3/4 × 1/6 = 1/8 ≈ 0.125.",
          "inputs_label": "3/4 × 1/6",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "g-divide",
        "reference": {
          "mode": "operate",
          "op": "/",
          "n": 9,
          "d": 2,
          "improper": "9/2"
        },
        "actual": {
          "mode": "operate",
          "op": "/",
          "n": 9,
          "d": 2,
          "improper": "9/2",
          "mixed": "4 1/2",
          "display": "4 1/2",
          "decimal": "4.5",
          "decimal_display": "4.5",
          "formula": "a/b ÷ c/d = a/b × d/c",
          "steps": [
            "3/4 ÷ 1/6",
            "Keep–change–flip: 3/4 × 6",
            "= 18/4",
            "GCF(18, 4) = 2",
            "Reduced result: 9/2",
            "Mixed: 4 1/2",
            "Decimal: 9 ÷ 2 ≈ 4.5"
          ],
          "explainer": "3/4 ÷ 1/6 = 9/2 = 4 1/2 ≈ 4.5.",
          "inputs_label": "3/4 ÷ 1/6",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "g-simplify",
        "reference": {
          "mode": "simplify",
          "n": 2,
          "d": 3,
          "improper": "2/3"
        },
        "actual": {
          "mode": "simplify",
          "n": 2,
          "d": 3,
          "improper": "2/3",
          "mixed": "2/3",
          "display": "2/3",
          "decimal": "0.666666666667",
          "decimal_display": "0.666666666667",
          "formula": "a/b = (a÷g)/(b÷g) where g = GCF(a, b)",
          "steps": [
            "Input: 12/18",
            "GCF(12, 18) = 6",
            "Reduced result: 2/3",
            "Decimal: 2 ÷ 3 ≈ 0.666666666667"
          ],
          "explainer": "12/18 → 2/3 ≈ 0.666666666667.",
          "inputs_label": "12/18",
          "heading": "Simplified",
          "mode_label": "Simplify"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "g-safe-limit",
        "reference": {
          "mode": "operate",
          "op": "+",
          "n": 9007199254740991,
          "d": 1,
          "improper": "9007199254740991"
        },
        "actual": {
          "mode": "operate",
          "op": "+",
          "n": 9007199254740991,
          "d": 1,
          "improper": "9007199254740991",
          "mixed": "9007199254740991",
          "display": "9007199254740991",
          "decimal": "9.00719925e+15",
          "decimal_display": "9.00719925e+15",
          "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
          "steps": [
            "9007199254740990 + 1",
            "LCD = LCM(1, 1) = 1",
            "9007199254740990 = 9007199254740990/1",
            "1 = 1/1",
            "9007199254740990/1 + 1/1 = 9007199254740991/1",
            "GCF(9007199254740991, 1) = 1",
            "9007199254740991 is already in lowest terms.",
            "Decimal: 9007199254740991 ÷ 1 ≈ 9.00719925e+15"
          ],
          "explainer": "9007199254740990 + 1 = 9007199254740991 ≈ 9.00719925e+15.",
          "inputs_label": "9007199254740990 + 1",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "golden"
      },
      {
        "id": "rt-add-sub",
        "reference": {
          "mode": "operate",
          "op": "+",
          "n": 11,
          "d": 12,
          "improper": "11/12"
        },
        "actual": {
          "mode": "operate",
          "op": "+",
          "n": 11,
          "d": 12,
          "improper": "11/12",
          "mixed": "11/12",
          "display": "11/12",
          "decimal": "0.916666666667",
          "decimal_display": "0.916666666667",
          "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
          "steps": [
            "3/4 + 1/6",
            "LCD = LCM(4, 6) = 12",
            "3/4 = 9/12",
            "1/6 = 2/12",
            "9/12 + 2/12 = 11/12",
            "GCF(11, 12) = 1",
            "11/12 is already in lowest terms.",
            "Decimal: 11 ÷ 12 ≈ 0.916666666667"
          ],
          "explainer": "3/4 + 1/6 = 11/12 ≈ 0.916666666667.",
          "inputs_label": "3/4 + 1/6",
          "heading": "Result",
          "mode_label": "Operate"
        },
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "round-trip",
        "hops": {
          "forward": {
            "reference": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12"
            },
            "actual": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12",
              "mixed": "11/12",
              "display": "11/12",
              "decimal": "0.916666666667",
              "decimal_display": "0.916666666667",
              "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
              "steps": [
                "3/4 + 1/6",
                "LCD = LCM(4, 6) = 12",
                "3/4 = 9/12",
                "1/6 = 2/12",
                "9/12 + 2/12 = 11/12",
                "GCF(11, 12) = 1",
                "11/12 is already in lowest terms.",
                "Decimal: 11 ÷ 12 ≈ 0.916666666667"
              ],
              "explainer": "3/4 + 1/6 = 11/12 ≈ 0.916666666667.",
              "inputs_label": "3/4 + 1/6",
              "heading": "Result",
              "mode_label": "Operate"
            },
            "error_ulp": 0
          },
          "reverse": {
            "reference": {
              "mode": "operate",
              "op": "-",
              "n": 3,
              "d": 4,
              "improper": "3/4"
            },
            "actual": {
              "mode": "operate",
              "op": "-",
              "n": 3,
              "d": 4,
              "improper": "3/4",
              "mixed": "3/4",
              "display": "3/4",
              "decimal": "0.75",
              "decimal_display": "0.75",
              "formula": "L = LCM(b, d); a/b − c/d = [a(L/b) − c(L/d)] / L",
              "steps": [
                "11/12 − 1/6",
                "LCD = LCM(12, 6) = 12",
                "11/12 = 11/12",
                "1/6 = 2/12",
                "11/12 − 2/12 = 9/12",
                "GCF(9, 12) = 3",
                "Reduced result: 3/4",
                "Decimal: 3 ÷ 4 ≈ 0.75"
              ],
              "explainer": "11/12 − 1/6 = 3/4 ≈ 0.75.",
              "inputs_label": "11/12 − 1/6",
              "heading": "Result",
              "mode_label": "Operate"
            },
            "error_ulp": 0
          }
        }
      },
      {
        "id": "meta-commute-add",
        "reference": 1,
        "actual": 1,
        "error_ulp": 0,
        "threshold_ulp": 0,
        "suite": "metamorphic",
        "hops": {
          "base": {
            "reference": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12"
            },
            "actual": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12",
              "mixed": "11/12",
              "display": "11/12",
              "decimal": "0.916666666667",
              "decimal_display": "0.916666666667",
              "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
              "steps": [
                "3/4 + 1/6",
                "LCD = LCM(4, 6) = 12",
                "3/4 = 9/12",
                "1/6 = 2/12",
                "9/12 + 2/12 = 11/12",
                "GCF(11, 12) = 1",
                "11/12 is already in lowest terms.",
                "Decimal: 11 ÷ 12 ≈ 0.916666666667"
              ],
              "explainer": "3/4 + 1/6 = 11/12 ≈ 0.916666666667.",
              "inputs_label": "3/4 + 1/6",
              "heading": "Result",
              "mode_label": "Operate"
            },
            "error_ulp": 0
          },
          "follow": {
            "reference": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12"
            },
            "actual": {
              "mode": "operate",
              "op": "+",
              "n": 11,
              "d": 12,
              "improper": "11/12",
              "mixed": "11/12",
              "display": "11/12",
              "decimal": "0.916666666667",
              "decimal_display": "0.916666666667",
              "formula": "L = LCM(b, d); a/b + c/d = [a(L/b) + c(L/d)] / L",
              "steps": [
                "1/6 + 3/4",
                "LCD = LCM(6, 4) = 12",
                "1/6 = 2/12",
                "3/4 = 9/12",
                "2/12 + 9/12 = 11/12",
                "GCF(11, 12) = 1",
                "11/12 is already in lowest terms.",
                "Decimal: 11 ÷ 12 ≈ 0.916666666667"
              ],
              "explainer": "1/6 + 3/4 = 11/12 ≈ 0.916666666667.",
              "inputs_label": "1/6 + 3/4",
              "heading": "Result",
              "mode_label": "Operate"
            },
            "error_ulp": 0
          },
          "relation": {
            "reference": 1,
            "actual": 1,
            "error_ulp": 0
          }
        }
      }
    ]
  },
  "interfaces": {
    "compared": [
      "ui-ssr",
      "rest",
      "mcp"
    ],
    "result": "PASS",
    "notes": "UI (SSR) · REST · MCP equivalent (MCP uses calc API handler). ui-ssr is query-result HTML, not a live browser session."
  },
  "artifacts": {
    "evidence_bundle_sha256": "d93a4bc59778bf9cce65eb0ab54b47f80998830ac9c28ad67b9081f191c430f8",
    "evidence_digest": "b2e72767e4a472f8653cf92667f7b0a184099666f5c599ae67ff9de8e85285c3",
    "production_sha256": "8a224dbdcd21223942d0e73df9a3c58e3b2c63d744bd5164790a86cc92da0fc9",
    "attested_catalog_sha256": "6186d9f9c642e2b117ca4b72014d212f663656bb36624b7c12dbc67c29ee9f34",
    "production_checks": [
      {
        "id": "math.fractions:output-const",
        "status": "pass",
        "detail": "output const 1.0.5 vs capability 1.0.5",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      },
      {
        "id": "math.fractions:evidence-sha256",
        "status": "pass",
        "detail": "c5a68d1949bc",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      },
      {
        "id": "math.fractions:semantic-contract",
        "status": "pass",
        "detail": "32/32",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      },
      {
        "id": "math.fractions:capability-html-public-origin-agree",
        "status": "pass",
        "detail": "public 1.0.5 vs origin 1.0.5",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      },
      {
        "id": "math.fractions:cvp-manifest-public-origin-agree",
        "status": "pass",
        "detail": "math.fractions/1.0.6/2026-09-30.safe-integer-scope/core/b2e72767e4a4",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z",
        "projection_compared": false
      },
      {
        "id": "math.fractions:cvp-latest-alias-agrees",
        "status": "pass",
        "detail": "math.fractions/1.0.6/2026-09-30.safe-integer-scope/core/b2e72767e4a4",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z",
        "projection_compared": false
      },
      {
        "id": "math.fractions:calculator-html-cvp-projection",
        "status": "pass",
        "detail": "matches Trust display",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      },
      {
        "id": "math.fractions:evidence-html-cvp-projection",
        "status": "pass",
        "detail": "matches Trust display",
        "scope": "last_attestation_snapshot",
        "current": false,
        "attestation_binding_current": false,
        "attested_at": "2026-09-30T13:14:02.480Z"
      }
    ],
    "digest_registry": {
      "digest_algorithm": "sha256",
      "canonicalization": "json-sorted-keys-utf8",
      "entries": [
        {
          "name": "cvp_core_sha256",
          "field": "artifacts.cvp_core_sha256",
          "digest_scope": "cvp_verification_fingerprint_v2",
          "value": "b2e72767e4a472f8653cf92667f7b0a184099666f5c599ae67ff9de8e85285c3",
          "note": "Immutable verification core; excludes attestation/live-status and Evidence contract counts"
        },
        {
          "name": "cvp_evidence_digest",
          "field": "artifacts.evidence_digest",
          "digest_scope": "cvp_verification_fingerprint_v2",
          "value": "b2e72767e4a472f8653cf92667f7b0a184099666f5c599ae67ff9de8e85285c3",
          "note": "Alias of cvp_core_sha256 (historical field name)"
        },
        {
          "name": "artifact_evidence_sha256",
          "field": "release_integrity.digests.evidence_core_sha256",
          "digest_scope": "evidence_artifact_core",
          "value": "58a1ffd4b572e7279bb5eaff844bdef97061318321fa9ed52913d79ef9ce5d2c",
          "note": "Published Evidence JSON core — Trust freshness / production bind subject"
        },
        {
          "name": "evidence_catalog_digest",
          "field": "artifacts.attested_catalog_sha256",
          "digest_scope": "capability_catalog",
          "value": "6186d9f9c642e2b117ca4b72014d212f663656bb36624b7c12dbc67c29ee9f34",
          "note": "Capability catalog integrity; site-wide, not per-suite fingerprint"
        }
      ]
    },
    "cvp_core_sha256": "b2e72767e4a472f8653cf92667f7b0a184099666f5c599ae67ff9de8e85285c3"
  },
  "dependencies": [
    {
      "name": "fractions-engine",
      "version": "1.0.6"
    },
    {
      "name": "fractions-reference-oracle",
      "version": "1.0.0"
    },
    {
      "name": "node",
      "version": "20.19.2"
    }
  ],
  "attestation": {
    "status": "STALE",
    "href": "/.well-known/calculatorx-production-attestation.json",
    "id": "b6db86a3946922a6529492107ca8043828115b3ffd21d9c4669ff69fb7f854ce",
    "attested_at": "2026-09-30T13:14:02.480Z",
    "last_confirmed_current_at": "2026-09-30T13:14:02.480Z",
    "site_attestation_current": false,
    "capability_attestation_current": false,
    "bound_snapshot_status": "pass",
    "live_report_status": "stale",
    "bound_attested_at": "2026-09-29T09:41:45.368Z",
    "live_updated_at": "2026-09-30T13:14:02.602Z",
    "bound_snapshot": {
      "status": "pass",
      "attested_at": "2026-09-29T09:41:45.368Z",
      "site_stale_count": 1
    },
    "live_site_status": {
      "href": "/.well-known/calculatorx-production-attestation.json"
    },
    "bound_snapshot_site_stale_count": 1,
    "site_stale_capability_count": 1,
    "stale_reason": "Capability production binding: STALE · Site report: STALE · Evidence changed after the last successful production attestation. Re-attestation required.",
    "evidence_attested_at": "2026-09-30T13:14:02.480Z"
  },
  "domain_review": {
    "status": "ABSENT",
    "spec_version": "1.0.6",
    "external_third_party": false,
    "note": "Named expert review not performed"
  },
  "timestamps": {
    "verified_at": "2026-09-30T13:14:02.480Z",
    "generated_at": "2026-09-30T13:14:02.480Z",
    "rendered_at": "2026-09-30T13:41:27.655Z",
    "notes": "verified_at/generated_at mark the first publication of this cvp_core_sha256 (artifacts.evidence_digest alias) for suite verification. evidence_attested_at/attested_at is the first production bind of that core digest. last_confirmed_current_at is the latest site-wide report that still confirms CURRENT. rendered_at is this JSON serialization and is not part of cvp_core_sha256 / evidence_digest. Production attestation binds cvp_core_sha256 (binds evidence_digest). Causal order: verified_at ≤ evidence_attested_at ≤ last_confirmed_current_at. attestation.bound_snapshot.site_stale_count is the site-wide stale capability count at Manifest bind time — not a live value. Fetch attestation.live_site_status.href for the current site report."
  },
  "links": {
    "legacy_evidence": "https://www.calculatorx.com/evidence/math.fractions/1.0.6.json",
    "evidence_page": "https://www.calculatorx.com/evidence/math.fractions/1.0.6",
    "calculator": "https://www.calculatorx.com/calc/math/fractions",
    "schema": "https://www.calculatorx.com/developers/cvp/schema/cvp-evidence-1.0.json",
    "protocol": "https://www.calculatorx.com/developers/cvp/spec/1.0",
    "manifest": "https://www.calculatorx.com/evidence/math.fractions/1.0.6.cvp.json",
    "manifest_immutable": "https://www.calculatorx.com/evidence/math.fractions/1.0.6/2026-09-30.safe-integer-scope.cvp.json",
    "manifest_core": "https://www.calculatorx.com/evidence/math.fractions/1.0.6/2026-09-30.safe-integer-scope.b2e72767e4a4.cvp.json"
  }
}