{
  "protocol": {
    "name": "CVP",
    "version": "1.0.0-proposed"
  },
  "document_status": "proposed",
  "calculator": {
    "id": "lpf",
    "version": "1.0.0",
    "title": "Low-Pass Filter Calculator",
    "formula_family": "rc-lpf",
    "capability_id": "electrical.lpf"
  },
  "profile": "engineering",
  "status": "VERIFIED",
  "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": "lpf",
    "version": "1.0.0",
    "uri": "https://www.calculatorx.com/evidence/electrical.lpf/1.0.0.json"
  },
  "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-DIM-01",
    "CVP-PROP-01",
    "CVP-IFACE-01"
  ],
  "provenance": {
    "mode": "direct",
    "sources": [
      {
        "label": "Horowitz & Hill — The Art of Electronics",
        "kind": "other",
        "reference": "Single-pole RC filters"
      },
      {
        "label": "IEC 60050 — IEV",
        "kind": "standard",
        "reference": "Cut-off frequency"
      }
    ]
  },
  "reference": {
    "items": [
      {
        "class": "O1",
        "reference_scope": "model",
        "scope": "model",
        "label": "First-order RC low-pass filter"
      },
      {
        "class": "O2",
        "reference_scope": "expected_values",
        "scope": "expected_values",
        "label": "Separate-module LPF oracle — same V8 binary64 as IUT",
        "engine": {
          "name": "lpf-reference",
          "precision_bits": 53,
          "independent_of_iut": true
        }
      },
      {
        "class": "O2",
        "reference_scope": "numerical_behavior",
        "scope": "numerical_behavior",
        "label": "Same O2 module backs ≤2 ULP fc comparison vs IUT",
        "engine": {
          "name": "lpf-reference",
          "precision_bits": 53,
          "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": "fc=1/(2πRC); any two of R,C,fc; optional |H(f)|"
    },
    "CVP-SCOPE-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "First-order RC LPF only"
    },
    "CVP-UNIT-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "Ω, F, Hz"
    },
    "CVP-REF-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "O1 model + O2 expected_values + O2 numerical_behavior"
    },
    "CVP-GOLD-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "3/3 legacy golden; 3/3 oracle-backed numeric"
    },
    "CVP-BND-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "3/3 boundary"
    },
    "CVP-INV-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "3 invalid-domain cases"
    },
    "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": "4/4 declared partitions (solve-rc, with-f, solve-C, invalid-domain) · 3 golden / 3 boundary unique cases · 3 Evidence invalid-input (may overlap boundary)"
    },
    "CVP-CONTRACT-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "1/1 contract checks"
    },
    "CVP-DEP-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "engine lpf; Node binary64"
    },
    "CVP-ART-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "release_integrity.status=verified · evidence_digest=CVP verification fingerprint v2 (canonical inputs, expected/actual/status, policy, versions; independent of generated_at) · evidence_bundle_sha256=legacy Evidence JSON bytes · production_sha256=bound production attestation report"
    },
    "CVP-PROD-01": {
      "result": "PASS",
      "applicability": "required",
      "notes": "CURRENT · site report pass · local checks pass · attestation_id=00c818a77ba026c2d6aa3f7402680cd2dac2a40a816209600bc3c3fcd0b8921c · CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓ · schema_const=1.0.0 · report output-const=pass · evidence-sha256=pass · semantic-contract=pass · capability-html-public-origin-agree=pass · cvp-manifest-public-origin-agree=pass · calculator-html-cvp-projection=pass · evidence-html-cvp-projection=pass · attested_evidence_sha256=9424f31d3ca937ec4a453e41479201945df6495214f0a220ebb742e7fd1c3f20"
    },
    "CVP-DIM-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "Cutoff frequency and magnitude"
    },
    "CVP-PROP-01": {
      "result": "PASS",
      "applicability": "applicable",
      "notes": "4/4 property"
    },
    "CVP-META-01": {
      "result": "SKIP",
      "applicability": "not_applicable",
      "notes": "No input→output transformation vectors in pack — control not in obligation set"
    },
    "CVP-ROUND-01": {
      "result": "SKIP",
      "applicability": "not_applicable",
      "notes": "No inverse / round-trip vectors in pack — control not in obligation set"
    },
    "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": "PASS",
      "applicability": "optional",
      "notes": "expert_reviewed=true"
    }
  },
  "tests": {
    "golden": {
      "passed": 3,
      "total": 3,
      "failed": 0,
      "case_ids": [
        "g-rc",
        "g-mag",
        "g-C"
      ]
    },
    "boundary": {
      "passed": 3,
      "total": 3,
      "failed": 0,
      "case_ids": [
        "needs-two",
        "zero-R",
        "nan-C"
      ]
    },
    "invalid": {
      "passed": 3,
      "total": 3,
      "failed": 0,
      "case_ids": [
        "needs-two",
        "zero-R",
        "nan-C"
      ]
    },
    "property": {
      "passed": 4,
      "total": 4,
      "failed": 0,
      "case_ids": [
        "property-fc",
        "property-3db",
        "property-solve-C",
        "property-half-fc"
      ],
      "kind": "fixed"
    },
    "round_trip": {
      "passed": 0,
      "total": 0,
      "failed": 0,
      "case_ids": []
    },
    "metamorphic": {
      "passed": 0,
      "total": 0,
      "failed": 0,
      "case_ids": []
    },
    "contract": {
      "passed": 1,
      "total": 1,
      "failed": 0
    },
    "cross_interface": {
      "passed": 1,
      "total": 1,
      "failed": 0,
      "case_ids": [
        "iface-rc"
      ]
    }
  },
  "coverage": {
    "partitions": [
      {
        "id": "solve-rc",
        "description": "R+C → fc",
        "exercised": true,
        "case_count": 2
      },
      {
        "id": "with-f",
        "description": "Magnitude at f",
        "exercised": true,
        "case_count": 2
      },
      {
        "id": "solve-C",
        "description": "R+fc → C",
        "exercised": true,
        "case_count": 2
      },
      {
        "id": "invalid-domain",
        "description": "Invalid inputs",
        "exercised": true,
        "case_count": 3
      }
    ]
  },
  "numerical": {
    "representation": "IEEE-754 binary64",
    "tolerance": {
      "type": "ulp",
      "value": 2,
      "rationale": "First-order RC LPF; ≤2 ULP vs separate-module O2 (same V8). Declared a priori.",
      "declared_before_evaluation": true
    },
    "max_error_observed": 0,
    "records": [
      {
        "id": "g-rc",
        "reference": {
          "R": 10000,
          "C": 0.000001,
          "fc": 15.915494309189533,
          "tau": 0.01,
          "omega_c": 100
        },
        "actual": {
          "R": 10000,
          "C": 0.000001,
          "fc": 15.915494309189533,
          "tau": 0.01,
          "omega_c": 100
        },
        "error_ulp": 0,
        "threshold_ulp": 2
      },
      {
        "id": "g-mag",
        "reference": {
          "R": 10000,
          "C": 0.000001,
          "fc": 15.915494309189533,
          "tau": 0.01,
          "omega_c": 100,
          "f": 15.915494309189533,
          "H_lin": 0.7071067811865475,
          "H_dB": -3.0102999566398125
        },
        "actual": {
          "R": 10000,
          "C": 0.000001,
          "fc": 15.915494309189533,
          "tau": 0.01,
          "omega_c": 100,
          "f": 15.915494309189533,
          "H_lin": 0.7071067811865475,
          "H_dB": -3.0102999566398125
        },
        "error_ulp": 0,
        "threshold_ulp": 2
      },
      {
        "id": "g-C",
        "reference": {
          "R": 4700,
          "C": 3.386275384933943e-8,
          "fc": 1000,
          "tau": 0.00015915494309189532,
          "omega_c": 6283.185307179586
        },
        "actual": {
          "R": 4700,
          "C": 3.386275384933943e-8,
          "fc": 1000,
          "tau": 0.00015915494309189532,
          "omega_c": 6283.185307179586
        },
        "error_ulp": 0,
        "threshold_ulp": 2
      }
    ]
  },
  "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": "5610110c1596e9391cccd5526b696014ed46df9e35b2e41076250fa9eb80467b",
    "evidence_digest": "00b0f72866605de42ca7ac2311f81cdd8a2d0056b909bdbdac124a7c69c84486",
    "production_sha256": "9424f31d3ca937ec4a453e41479201945df6495214f0a220ebb742e7fd1c3f20",
    "attested_catalog_sha256": "e03ef81b30568018b171fd1fc4757c2abe9df7220d9ff35bbaf08038d7630cdb",
    "production_checks": [
      {
        "id": "electrical.lpf:output-const",
        "status": "pass",
        "detail": "output const 1.0.0 vs capability 1.0.0",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      },
      {
        "id": "electrical.lpf:evidence-sha256",
        "status": "pass",
        "detail": "78966976955a",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      },
      {
        "id": "electrical.lpf:semantic-contract",
        "status": "pass",
        "detail": "10/10",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      },
      {
        "id": "electrical.lpf:capability-html-public-origin-agree",
        "status": "pass",
        "detail": "public 1.0.0 vs origin 1.0.0",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      },
      {
        "id": "electrical.lpf:cvp-manifest-public-origin-agree",
        "status": "pass",
        "detail": "electrical.lpf/1.0.0/-/engineering/00b0f7286660",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z",
        "projection_compared": false,
        "observed_live_projection_at_attestation": "VERIFIED"
      },
      {
        "id": "electrical.lpf:calculator-html-cvp-projection",
        "status": "pass",
        "detail": "matches Manifest",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      },
      {
        "id": "electrical.lpf:evidence-html-cvp-projection",
        "status": "pass",
        "detail": "matches Manifest",
        "scope": "last_attestation_snapshot",
        "current": true,
        "attestation_binding_current": true,
        "attested_at": "2026-09-10T02:52:51.379Z"
      }
    ]
  },
  "dependencies": [
    {
      "name": "lpf-engine",
      "version": "1.0.0"
    },
    {
      "name": "lpf-reference-oracle",
      "version": "1.0.0"
    },
    {
      "name": "node",
      "version": "20.19.2"
    }
  ],
  "attestation": {
    "status": "CURRENT",
    "href": "/.well-known/calculatorx-production-attestation.json",
    "id": "00c818a77ba026c2d6aa3f7402680cd2dac2a40a816209600bc3c3fcd0b8921c",
    "attested_at": "2026-09-10T02:52:51.379Z"
  },
  "domain_review": {
    "status": "PASS",
    "reviewer_role": "electrical-engineer",
    "spec_version": "1.0.0",
    "external_third_party": false,
    "independence": "internal"
  },
  "timestamps": {
    "verified_at": "2026-09-10T03:41:43.165Z",
    "generated_at": "2026-09-10T03:41:43.165Z"
  },
  "links": {
    "legacy_evidence": "https://www.calculatorx.com/evidence/electrical.lpf/1.0.0.json",
    "evidence_page": "https://www.calculatorx.com/evidence/electrical.lpf/1.0.0",
    "calculator": "https://www.calculatorx.com/calc/electric/lpf",
    "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/electrical.lpf/1.0.0.cvp.json"
  }
}