Public evidence

engineering.msa.gauge_capability

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

11/11 calculation tests · Production surface contract 4/4

Golden tests 0 / 0
Boundary tests 6 / 6
Property tests 5 / 5
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract PASS
Evidence attested at 2026-09-16T06:44:24.203Z
Last production check 2026-09-16T06:44:24.203Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:a7dfdfedfcf839816992c29c58b3dea40fd1fe7484554f97c9ab6690a526b421

Input schema sha256:998f7894d8a9bfaed09a02f68371e241d61c803fb91acf76bac795a079d1d990 · Output schema sha256:cabbf74da581239a11c95b10781ffa05ef4c0ada848e6027d8badd5ce8d4acf3 · 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.

Build & scope

Engine identity and declared limitations.

Tool: gauge-capability
Engine: gauge-capability
Engine build: 2026-09-15
Evidence core: 2026-09-15T10:14:13.310Z
Rendered: 2026-09-16T22:03:43.740Z
Last reviewed: —

Assumptions

Type-1 Cg = (frac·T)/(6s), Cgk = (frac·T/2 − |x̄−xm|)/(3s). frac defaults to 0.2 (Bosch / VDA 5).
s is overall sample s of repeats on a master. Not AIAG GRR, not Cp/Cpk, and not a Cg≥1.33 verdict.
Exactly one spec form: lsl+usl, T/span, or half-width tol
frac is a tolerance fraction (0 < frac ≤ 1), not coverage factor k

Limitations

Type-1 study on a master — not AIAG GRR compose (EV/AV/PV)
Not process Cp/Cpk or Pp/Ppk
Does not issue a Cg≥1.33 pass/fail
frac is a tolerance fraction (default 0.2), not coverage factor k

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

VDA Volume 5 — Capability of Measurement Processes — Type-1 study Cg, Cgk (20% of characteristic tolerance)
Supports: Cg = 0.2·T / (6s); Cgk includes bias against the master
ISO 22514-7 — Capability of measurement processes — Cg and Cgk from a Type-1 study on a reference
Supports: Gauge capability indices from repeats on a master versus a tolerance fraction

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`boundary-cg`	boundary	pass	Expected Cg=1 · Cgk=1 · s=1 · bias=0 · Actual n=3 · Cg=1 · Cgk=1 · s=1 · xbar=8 · xm=8 · bias=0 · T=30
`boundary-cg-bias`	boundary	pass	Expected Cg=1 · Cgk=0.6666666666666666 · Actual n=3 · Cg=1 · Cgk=0.6666666666666666 · s=1 · xbar=7 · xm=8 · bias=1 · T=30
`boundary-cg-n1`	boundary	pass	Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE
`boundary-cg-flat`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-cg-frac`	boundary	pass	Expected INVALID_INPUT · Actual INVALID_INPUT
`boundary-cg-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`property-cg`	property	pass	1
`property-cg-bias`	property	pass	2/3
`property-cg-limits`	property	pass	1
`property-cg-tol`	property	pass	1
`property-cg-frac`	property	pass	0.5