{ "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": "subtraction", "version": "1.0.2", "title": "Subtraction Calculator", "formula_family": "subtraction", "capability_id": "math.subtraction", "verification_revision": "2026-10-22.subtraction-complete-contract-v3" }, "profile": "core", "status": "VERIFIED", "verification_status": "VERIFIED", "production_freshness": "CURRENT", "overall_trust": "VERIFIED", "runner": { "name": "cvp-runner", "version": "1.0.0" }, "environment": { "runtime": "node", "runtime_version": "22.20.0", "numeric_model": "exact_integer", "os": "darwin" }, "suite": { "id": "subtraction", "version": "1.0.2", "uri": "https://www.calculatorx.com/evidence/math.subtraction/1.0.2.json", "verification_revision": "2026-10-22.subtraction-complete-contract-v3" }, "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": "CalculatorX mathematical conventions", "kind": "other", "reference": "Long subtraction with regrouping" }, { "label": "Margaret Stevens — The Maths Workbook (University of Oxford)", "kind": "other", "reference": "Chapter 1, §1: Algebraic Expressions and Fractions; §3: Equations", "url": "https://www.some.ox.ac.uk/wp-content/uploads/2024/08/Maths-Workbook.pdf" } ] }, "controls": { "CVP-PROV-01": { "result": "PASS", "applicability": "required", "notes": "Sources present on evidence" }, "CVP-MODEL-01": { "result": "PASS", "applicability": "required", "notes": "a − b = d" }, "CVP-SCOPE-01": { "result": "PASS", "applicability": "required", "notes": "Declared partitions are difference, solve-for-minuend, solve-for-subtrahend, long-normal, long-negative-result, invalid-domain — aligned with published capability modes. CPython independently checks full packs, exact scaled-integer differences and column borrowing, including negative-result sign." }, "CVP-UNIT-01": { "result": "PASS", "applicability": "required", "notes": "dimensionless" }, "CVP-REF-01": { "result": "PASS", "applicability": "required", "notes": "O1 subtraction model + independent CPython O2 complete expected values / numerical behavior" }, "CVP-GOLD-01": { "result": "PASS", "applicability": "required", "notes": "6/6 legacy golden; 82/82 oracle-backed numeric" }, "CVP-BND-01": { "result": "PASS", "applicability": "required", "notes": "1/1 CVP boundary · 1/1 legacy Evidence boundary" }, "CVP-INV-01": { "result": "PASS", "applicability": "required", "notes": "1 Evidence illegal-input + 4/4 oracle-backed error-code (exact_error_match, not ULP)" }, "CVP-NUM-01": { "result": "PASS", "applicability": "required", "notes": "82 independent complete packs across binary64 missing-term and exact bounded decimal Long branches; no exhaustive-domain proof. Legacy Evidence `tol` is not this policy." }, "CVP-COV-01": { "result": "PASS", "applicability": "required", "notes": "6/6 declared partitions (difference, solve-for-minuend, solve-for-subtrahend, long-normal, long-negative-result, invalid-domain) · 6 legacy golden / 1 CVP boundary unique cases · 1 Evidence invalid-input (may overlap boundary)" }, "CVP-CONTRACT-01": { "result": "PASS", "applicability": "required", "notes": "6/6 CVP contract · release-artifacts-aligned=PASS · schema-output-required-declared=PASS · schema-valid-input-executes=PASS · engine-success-output-validates-schema=PASS · schema-rejects-incomplete-input=PASS · rest-success-payload-validates-schema=PASS" }, "CVP-DEP-01": { "result": "PASS", "applicability": "required", "notes": "engine subtraction; 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": "this calculator CURRENT · bound snapshot pass @ 2026-10-23T02:35:45.524Z · live site-wide report stale @ 2026-10-23T02:36:37.348Z (5 other capabilities) · local checks pass · attestation_id=dca9793f9ed1f599a644097852f8f6d70c130711c521e71af00409d440f71bfc · This calculator CURRENT · This calculator is not affected · Bound attestation PASS @ 2026-10-23T02:35:45.524Z · Live production status STALE (5 capabilities; 371 remain CURRENT) @ 2026-10-23T02:36:37.348Z · Public schema 1.0.2 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓ · schema_const=1.0.2 · 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 · cvp-immutable-manifest-fetch=pass · cvp-immutable-manifest-sha256=pass · cvp-latest-alias-matches-immutable=pass · calculator-html-cvp-projection=pass · evidence-html-cvp-projection=pass · attested_evidence_sha256=5b662e4f79c2491b18c6059302ce20dc20428d229bda79ad0572e086ebd9b39e · verified_at=2026-10-22T10:11:38.122Z · evidence_attested_at=2026-10-22T10:11:38.122Z · last_confirmed_current_at=2026-10-23T02:35:45.524Z · rendered_at=2026-10-23T02:36:37.717Z · binds=cvp_core_sha256", "check_result": "PASS", "production_state": "CURRENT", "binding_current": true }, "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": "2/2 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. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only." }, "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" } }, "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. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only." }, "artifacts": { "evidence_bundle_sha256": "b66bc62ece446e1a76284ab971b49ae6a10be16a3caa6545173a6a576e124934", "evidence_digest": "a0f1f4f1c566736c7966eb0769d9d016e4e060ed8723971afcc591accac5bc83", "production_sha256": "5b662e4f79c2491b18c6059302ce20dc20428d229bda79ad0572e086ebd9b39e", "attested_catalog_sha256": "6378a203c9eb2e133d6b2592bf9741363d732d352c9bd3212fed3a1a50e00af6", "production_checks": [ { "id": "math.subtraction:output-const", "status": "pass", "detail": "output const 1.0.2 vs capability 1.0.2", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:evidence-sha256", "status": "pass", "detail": "73cea6764fb8", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:semantic-contract", "status": "pass", "detail": "7/7", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:capability-html-public-origin-agree", "status": "pass", "detail": "public 1.0.2 vs origin 1.0.2", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:cvp-manifest-public-origin-agree", "status": "pass", "detail": "math.subtraction/1.0.2/2026-10-22.subtraction-complete-contract-v3/core/a0f1f4f1c566", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z", "projection_compared": false }, { "id": "math.subtraction:cvp-latest-alias-agrees", "status": "pass", "detail": "math.subtraction/1.0.2/2026-10-22.subtraction-complete-contract-v3/core/a0f1f4f1c566", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z", "projection_compared": false }, { "id": "math.subtraction:cvp-immutable-manifest-fetch", "status": "pass", "detail": "public=200 origin=200", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:cvp-immutable-manifest-sha256", "status": "pass", "detail": "a0f1f4f1c566", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:cvp-latest-alias-matches-immutable", "status": "pass", "detail": "math.subtraction/1.0.2/2026-10-22.subtraction-complete-contract-v3/core/a0f1f4f1c566", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z", "projection_compared": false }, { "id": "math.subtraction:calculator-html-cvp-projection", "status": "pass", "detail": "matches Trust display", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" }, { "id": "math.subtraction:evidence-html-cvp-projection", "status": "pass", "detail": "matches Trust display", "scope": "last_attestation_snapshot", "current": true, "attestation_binding_current": true, "attested_at": "2026-10-22T10:11:38.122Z" } ], "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": "a0f1f4f1c566736c7966eb0769d9d016e4e060ed8723971afcc591accac5bc83", "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": "a0f1f4f1c566736c7966eb0769d9d016e4e060ed8723971afcc591accac5bc83", "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": "73cea6764fb8fb66701c44192bac87dc249e5690978ae6b9e7d3064d0fe4fb18", "note": "Published Evidence JSON core — Trust freshness / production bind subject" }, { "name": "evidence_catalog_digest", "field": "artifacts.attested_catalog_sha256", "digest_scope": "capability_catalog", "value": "6378a203c9eb2e133d6b2592bf9741363d732d352c9bd3212fed3a1a50e00af6", "note": "Capability catalog integrity; site-wide, not per-suite fingerprint" } ] }, "cvp_core_sha256": "a0f1f4f1c566736c7966eb0769d9d016e4e060ed8723971afcc591accac5bc83" }, "dependencies": [ { "name": "subtraction-engine", "version": "1.0.2" }, { "name": "subtraction-reference-oracle", "version": "1.0.0" }, { "name": "node", "version": "22.20.0" } ], "attestation": { "status": "CURRENT", "href": "/.well-known/calculatorx-production-attestation.json", "id": "dca9793f9ed1f599a644097852f8f6d70c130711c521e71af00409d440f71bfc", "attested_at": "2026-10-22T10:11:38.122Z", "last_confirmed_current_at": "2026-10-23T02:35:45.524Z", "site_attestation_current": false, "capability_attestation_current": true, "bound_snapshot_status": "pass", "live_report_status": "stale", "bound_attested_at": "2026-10-23T02:35:45.524Z", "live_updated_at": "2026-10-23T02:36:37.348Z", "bound_snapshot": { "status": "pass", "attested_at": "2026-10-23T02:35:45.524Z", "site_stale_count": 5 }, "live_site_status": { "href": "/.well-known/calculatorx-production-attestation.json" }, "bound_snapshot_site_stale_count": 5, "site_stale_capability_count": 5, "evidence_attested_at": "2026-10-22T10:11:38.122Z" }, "domain_review": { "status": "ABSENT", "spec_version": "1.0.2", "external_third_party": false, "note": "Named expert review not performed" }, "timestamps": { "verified_at": "2026-10-22T10:11:38.122Z", "generated_at": "2026-10-22T10:11:38.122Z", "rendered_at": "2026-10-23T02:36:37.717Z", "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." }, "tests": { "golden": { "passed": 82, "total": 82, "failed": 0 }, "boundary": { "passed": 1, "total": 1, "failed": 0 }, "invalid": { "passed": 5, "total": 5, "failed": 0, "comparison": "exact_error_match" }, "property": { "passed": 2, "total": 2, "failed": 0 }, "round_trip": { "passed": 2, "total": 2, "failed": 0 }, "metamorphic": { "passed": 1, "total": 1, "failed": 0 }, "contract": { "passed": 6, "total": 6, "failed": 0 }, "cross_interface": { "passed": 7, "total": 7, "failed": 0 } }, "numerical": { "representation": "binary64 Difference; exact scaled-decimal Long display/exact_value; numeric fields approximate", "tolerance": { "type": "exact", "value": 0, "declared_before_evaluation": true, "rationale": "Complete output packs vs independent CPython Fraction/Decimal/scaled integers; sampled domain, not exhaustive." }, "claim_scope": "82 independent complete packs across binary64 missing-term and exact bounded decimal Long branches; no exhaustive-domain proof.", "ulp_applicable": false, "exact_mismatches": 0 }, "coverage": { "partitions": [ { "id": "difference", "description": "Difference mode: minuend and subtrahend given, solve a − b", "exercised": true, "case_count": 45 }, { "id": "solve-for-minuend", "description": "Difference mode: solve minuend from subtrahend and difference", "exercised": true, "case_count": 8 }, { "id": "solve-for-subtrahend", "description": "Difference mode: solve subtrahend from minuend and difference", "exercised": true, "case_count": 7 }, { "id": "long-normal", "description": "Long subtraction with non-negative inputs and minuend ≥ subtrahend", "exercised": true, "case_count": 21 }, { "id": "long-negative-result", "description": "Long subtraction with minuend on top when minuend < subtrahend (negative difference)", "exercised": true, "case_count": 12 }, { "id": "invalid-domain", "description": "Missing terms, long-mode negatives / scientific notation, invalid mode", "exercised": true, "case_count": 5 } ] }, "reference": { "items": [ { "class": "O1", "reference_scope": "model", "scope": "model", "label": "Subtraction as inverse of addition" }, { "class": "O2", "reference_scope": "expected_values", "scope": "expected_values", "label": "Independent CPython Fraction / Decimal / scaled integers", "engine": { "name": "CPython", "precision_bits": 53, "independent_of_iut": true, "same_runtime_as_iut": false, "generator_sha256": "e3c7fe89cbcb5b62ae9874860bd3ed753dd691787a81bc869cf6cf958d2ef546" } }, { "class": "O2", "reference_scope": "numerical_behavior", "scope": "numerical_behavior", "label": "Independent CPython Fraction / Decimal / scaled integers", "engine": { "name": "CPython", "precision_bits": 53, "independent_of_iut": true, "same_runtime_as_iut": false, "generator_sha256": "e3c7fe89cbcb5b62ae9874860bd3ed753dd691787a81bc869cf6cf958d2ef546" } } ] }, "links": { "legacy_evidence": "https://www.calculatorx.com/evidence/math.subtraction/1.0.2.json", "evidence_page": "https://www.calculatorx.com/evidence/math.subtraction/1.0.2", "calculator": "https://www.calculatorx.com/calc/math/subtraction", "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.subtraction/1.0.2.cvp.json", "manifest_immutable": "https://www.calculatorx.com/evidence/math.subtraction/1.0.2/2026-10-22.subtraction-complete-contract-v3.cvp.json", "manifest_core": "https://www.calculatorx.com/evidence/math.subtraction/1.0.2/2026-10-22.subtraction-complete-contract-v3.a0f1f4f1c566.cvp.json" }, "disclosure": { "policy": "calculatorx-public-evidence-v1", "full_validation": "private", "representation": "summary" } }