Public evidence

engineering.conformity.mpe

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

9/9 calculation tests · Production surface contract 4/4

Golden tests 0 / 0
Boundary tests 6 / 6
Property tests 3 / 3
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: unpublished · Build schema 1.0.0 ready · Semantic contract ✓ · Attestation report not published on origin · Live production status STALE (1 capability; 156 remain CURRENT) @ 2026-09-14T03:54:53.650Z
Semantic contract PASS
Evidence attested at 2026-09-14T00:43:05.498Z
Last production check 2026-09-14T00:43:05.498Z
Public / cache —
Origin —
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:d60b3b1bd432f1a66b970ff8c8228776b5c4b8577d7123e310ed7845312b5867

Input schema sha256:f46350d3c456a33849b47261fe8c5b53ebd11c23bca09c60760a4c853dd7ecb1 · Output schema sha256:a16fcd486b3e1003d9faa33ff7e7516fb01aab2163e189a1429cfea82344d197 · 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: mpe
Engine: mpe
Engine build: 2026-09-15
Evidence core: 2026-09-15T14:57:22.092Z
Rendered: 2026-09-15T23:38:12.905Z
Last reviewed: —

Assumptions

VIM maximum permissible measurement error: pass iff |ylab−xref| ≤ MPE
Equality is pass. ratio = |ε|/MPE
Not an ILAC G8 spec decision on y, not En, and not ε without a limit
U, Ulab, and T are not aliases for MPE

Limitations

Binary |ε| ≤ MPE — equality is pass
Does not compare y to LSL/USL (use the decision-rule page)
Does not divide by U (that is En) and does not report ε without a limit
U, Ulab, and T are not aliases for MPE

Sources

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

JCGM 200:2012 — International vocabulary of metrology (VIM) — 4.26 maximum permissible measurement error (maximum permissible error, limit of error)
Supports: MPE is the extreme value of measurement error permitted by specifications or regulations. Pass iff |ε| ≤ MPE.
ISO 14253-1 — Geometrical product specifications (GPS) — Inspection by measurement of workpieces and measuring equipment — Decision rules vs MPE of a measuring equipment
Supports: MPE is a stated error limit of the measuring equipment, not an ILAC G8 specification decision on the workpiece characteristic y

Published checks

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

ID	Kind	Status	Detail
`boundary-mpe`	boundary	pass	Expected error=0.5 · ratio=0.5 · decision=pass · Actual error=0.5 · MPE=1 · abs_error=0.5 · ratio=0.5 · decision=pass · ylab=2.5 · xref=2
`boundary-mpe-eq`	boundary	pass	Expected ratio=1 · decision=pass · Actual error=0.5 · MPE=0.5 · abs_error=0.5 · ratio=1 · decision=pass · ylab=2.5 · xref=2
`boundary-mpe-fail`	boundary	pass	Expected ratio=2 · decision=fail · Actual error=2 · MPE=1 · abs_error=2 · ratio=2 · decision=fail · ylab=4 · xref=2
`boundary-mpe-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-mpe-ulab`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-mpe-zero`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`property-mpe`	property	pass	0.5
`property-mpe-eq`	property	pass	1
`property-mpe-fail`	property	pass	fail