Verified calculation capability

Measurement error Calculation Capability

VIM measurement error ε = ylab − xref (signed). Relative error is ε/xref when xref ≠ 0. Not percent error (×100), not En, not zeta, and not a z-score. · Engineering · Measurement

Capability ID engineering.measurement.error · version 1.0.0

Open calculator REST API MCP Evidence Evidence JSON Review policy

Model

Measurement error

Measurement error: ε = ylab − xref
Relative error: ε_rel = ε / xref (xref ≠ 0)

Inputs / Outputs

Canonical symbols for this capability. Agent schemas remain the contract.

Symbol	Quantity	Unit	Role
`ylab`	Measured quantity value. Aliases: y, x, measured.	—	input / output
`xref`	Reference quantity value. Aliases: X, ref, reference.	—	input / output
`error`	Signed measurement error ylab − xref	—	output
`abs_error`	—	—	output
`relative`	ε/xref when xref ≠ 0; otherwise null	—	output

Assumptions / Validity

Declared scope for this capability. Do not use it outside this domain.

Assumptions

VIM measurement error ε = ylab − xref (signed). Relative error is ε/xref when xref ≠ 0.
Not percent error (×100), not En, not zeta, not z-score, and not an ILAC G8 spec decision.

Not supported

percent error (×100)
En
zeta
z-score
ILAC G8 spec decision
bias from a sample of repeats (that is Accuracy)

Example

One numerical check. The calculator page holds worked steps and FAQ.

ylab=2.5 xref=2 → ε=0.5 ε_rel=0.25

Open this example in the calculator

Trust

Review-policy: engine tested — automated tests, sources, version lock, and evidence published. Supplemental to CVP; not Domain Expert Review. See CVP and Review policy.

Tier: Engine tested — catalog token engine_tested
Calculation version: 1.0.0
Evidence tests: 6/6 calculation tests · golden 0/0 · boundary 3/3 · property 3/3
Engine tested: Yes
Source checked: Yes
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.0.0 (workspace artifacts agree)

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

Call this capability

Human page, REST, and MCP share the same engine and calculation_version. Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Reference Calculation Standard — Production surface contract 4/4.

Tool id: measurement-error
Engine: measurement-error
REST: POST /api/v1/calc/measurement-error
MCP: execute_calculation with capability_id: "engineering.measurement.error"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.0.0)
Versioned output schema: Immutable pin (1.0.0)

References

Human-readable sources plus CVP reference evidence classes.

Sources

JCGM 200:2012 — International vocabulary of metrology (VIM) — 2.16 measurement error; 2.17 relative measurement error
ISO 13528 — Statistical methods for use in proficiency testing by interlaboratory comparison — z, zeta, and En are different contracts

Try with an agent

Inspect this capability via same-origin MCP, then call execute_calculation.

curl -sS -X POST 'https://www.calculatorx.com/mcp' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: inspect_capability' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"engineering.measurement.error"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.0.0) when reproducibility matters. Full protocol notes: MCP docs.