Public evidence

engineering.process.performance

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

7/7 calculation tests · Production surface contract 4/4

Golden tests 0 / 0
Boundary tests 5 / 5
Property tests 2 / 2
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 sha256:22614c70235c4c07084ec6e4fd856b0513c7f1ae3ce5d785208c8240010db3e2

Input schema sha256:1421bcba6a171b6f174fcf29bda8269bf7a7c30b69374b6b3e861374f21d2e72 · Output schema sha256:4424425260b9fa1a3e5340e56eba207edcf7eadc5a26a53fba28fa685481bd02 · 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: process-performance
Engine: process-performance
Engine build: 2026-09-15
Evidence core: 2026-09-15T09:55:28.150Z
Rendered: 2026-09-16T22:03:43.733Z
Last reviewed: —

Assumptions

Overall sample s via summarizeSample (ddof=1 default) — not a stated design σ
Not design-stage Cp/Cpk and not Type A u_A
Not within-subgroup SPC and not Monte Carlo simulated indices
Two-sided limits; USL > LSL

Limitations

Overall sample s — not a stated design σ and not within-subgroup SPC
Not design-stage Cp/Cpk and not Type A u_A = s/√n
Not Monte Carlo simulated indices
Two-sided LSL/USL required; USL must be greater than LSL

Sources

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

NIST Engineering Statistics Handbook — Process Capability — 6.1.6 What is Process Capability?
Supports: Pp/Ppk use overall (long-term) variation; Cp/Cpk use a stated or within σ
AIAG SPC — Statistical Process Control — Process performance indices Pp, Ppk
Supports: Pp and Ppk use overall sample standard deviation

Published checks

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

ID	Kind	Status	Detail
`boundary-ppk`	boundary	pass	Expected Pp=1 · Ppk=1 · mu=6 · sigma=2 · Actual n=3 · Pp=1 · Ppk=1 · Ppu=1 · Ppl=1 · mu=6 · sigma=2 · ddof=1
`boundary-ppk-shift`	boundary	pass	Expected Pp=2 · Ppk=1.3333333333333333 · Actual n=3 · Pp=2 · Ppk=1.3333333333333333 · Ppu=1.3333333333333333 · Ppl=2.6666666666666665 · mu=8 · sigma=1 · ddof=1
`boundary-ppk-n1`	boundary	pass	Expected VALUE_OUT_OF_RANGE · Actual VALUE_OUT_OF_RANGE
`boundary-ppk-flat`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-ppk-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`property-ppk`	property	pass	1
`property-ppk-shift`	property	pass	4/3