Verified calculation capability

Greatest common factor Calculation Capability

Exact GCF/GCD/HCF of two or more integers via BigInt pairwise Euclidean fold, with factor and prime independent checks when values are small enough to list. · Math

Capability ID math.gcf · version 1.0.2

Open calculator REST API MCP Evidence Evidence JSON CVP Manifest Review policy

Model

Pairwise

Pairwise: GCF(a,b,c,…) = GCF(GCF(a,b),c,…)
Euclidean: GCF(a,b) = GCF(b, a mod b) until remainder 0
With zero: GCF(k, 0) = |k| (k ≠ 0); all zeros undefined
Fractions: a/b = (a÷g)/(b÷g) where g = GCF(a,b)

Inputs / Outputs

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

Symbol	Quantity	Unit	Role
`values`	Two or more integers. Values beyond IEEE-754 safe integers must be decimal strings.	—	input / output
`numbers`	Alias for values	—	input
`numsInput`	Share-URL / form field: comma- or space-separated integers	—	input
`value`	Positive GCF as a JSON number when it fits IEEE-754 safe integers; otherwise the exact decimal string	—	output
`exact`	—	—	output
`count`	—	—	output
`formula`	—	—	output
`binary_formula`	—	—	output
`methods`	—	—	output
`work`	—	—	output
`max_digits`	—	—	output

Assumptions / Validity

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

Assumptions

Integer inputs; negatives treated by absolute value.
Zeros are ignored unless every input is 0.
GCF of a set of all zeros is undefined.

Example

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

GCF(8,12,20)=4; GCF(0,0,5)=5; GCF(9007199254740993, 3)=3

Open this example in the calculator

Trust

CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance. Computational verification is defined by CVP. Supplemental domain review (internal) and named expert review are defined by the Review policy and do not by themselves determine CVP conformance.

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance· View Manifest · CVP overview · Specification
Assurance: Core
Declared partition coverage: PASS · 8/8 declared partitions (gcf, zero, negative, beyond-safe-integer, multi-input-fold, method-unavailable, xcal, invalid-domain)
Calculation version: 1.0.2
Verification: 20/20 calculation tests · 6/6 legacy golden · 7/7 legacy boundary · 7/7 legacy property
Production surface contract: 3/3
Versions: Calculation 1.0.2 · CVP protocol 1.0.0-proposed · Evidence 2026-09-16.sources-no-wolfram
Verification revision: 2026-09-16.sources-no-wolfram · 3/3 property · digest 2f7e2bf9bb70
Reference: O1 model · O2 expected_values · O2 numerical_behavior
Interfaces: PASS · UI (SSR) / REST / MCP
ui-ssr is query-result HTML, not a live browser session.
CVP suite: 4/4 golden · 7/7 CVP boundary · 5/5 invalid · 3/3 property · 1/1 metamorphic · 1/1 cross-interface · 5/5 cross-calculator · 3/3 CVP contract
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.0.2 (workspace artifacts agree)
Review-policy tier: Engine tested — catalog token engine_tested; supplemental; not CVP status

This calculator CURRENT · Public schema 1.0.2 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

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 3/3.

Tool id: gcf
Engine: gcf
REST: POST /api/v1/calc/gcf
MCP: execute_calculation with capability_id: "math.gcf"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.0.2)
Versioned output schema: Immutable pin (1.0.2)

References

Human-readable sources plus CVP reference evidence classes.

Sources

Encyclopedia of Mathematics — Greatest common divisor — Definition; pairwise fold; prime-factor form
Encyclopedia of Mathematics — Euclidean algorithm — Remainder recurrence GCF(a,b)=GCF(b, a mod b)
CalculatorX integer convention — Absolute value; zero-set; 48-digit BigInt domain

Reference evidence classes: O1 model · O2 expected_values · O2 numerical_behavior

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":"math.gcf"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.0.2) when reproducibility matters. Full protocol notes: MCP docs.