engineering.measurement.precision

Three distinct suites: educational examples on the calculator page, this legacy regression count (11/11 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-25.o2-o3. Calculation version 1.0.1. CVP 1.0.0-proposed. 4/4 golden · 5/5 CVP boundary · 4/4 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 6/6 CVP contract. digest 432e5f2065c0. O2: repeatability s, CV, and r = 2.8 s vs a separate-module sample identity (≤2 ULP). Not Type A u_A. ≤2 ULP vs O3 applies only to the published tabulated precision vectors. Not Type A uncertainty.

• Golden (oracle-backed) 4 / 4
• CVP boundary 5 / 5
• Invalid input 4 / 4
• Property 1 / 1
• Metamorphic 1 / 1
• O3 high-precision 8 / 8
• Cross-interface 2 / 2
• CVP contract 6 / 6
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim 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.
• Verified scope Repeatability s, CV = s/|x̄|, and r = 2.8 s from a sample, + O3 mpmath tabulated precision.
• Assurance Engineering
• Deferred Not Type A uncertainty and not Gauge R&R.

• 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

Fingerprint sha256:20b0e0502040bc90914d4f7d3781589d15bf24781701290cca61ea4e0a2e42f0

Input schema sha256:d22d8b50bcb4ff55ce899f141ca46e040a64db7b88513714880f426e65028cb0 · Output schema sha256:661330b4dfa40adf9e45c5359f0d7cd64a21d783f07d8cd31eec5abbf00ba02d · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Tool

precision

Engine

precision

Engine build

2026-09-24

Evidence core

2026-09-24T22:15:34.591Z

Rendered

2026-10-23T01:27:11.177Z

Last reviewed

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Assumptions

• ISO 5725 repeatability: s from summarizeSample, CV = s/|x̄| when x̄ ≠ 0, r = 2.8·s.
• Not Type A u_A = s/√n, not Gauge R&R EV, and not percent CV (×100).

Limitations

• r = 2.8·s is the ISO 5725 conventional repeatability limit, not coverage factor k
• Does not report Type A u_A = s/√n
• Not Gauge R&R repeatability (EV)
• CV is not multiplied by 100; CV is undefined when x̄ = 0