CVP verified calculation capability

GPA ↔ letter grade Calculation Capability

Approximate GPA↔letter lookup on plus/minus 4.33, flat 4.0, or linear 5.0 normalization. One table, two SEO entries (GPA→letter and letter→GPA).

Education Capability ID education.gpa_letter version 1.1.3 CVP VERIFIED CURRENT Core

Model

Nearest

Nearest: Matched point = nearest gᵢ (ties → higher letter)
Floor: Matched point = max { gᵢ | gᵢ ≤ GPA }
Letter: Letter = letter for matched point

Modes: to-letter · to-gpa

Inputs / Outputs

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

Symbol	Quantity	Unit	Role
`gpa`	Numeric GPA for to-letter	—	input
`letter`	Letter grade for to-gpa	—	input / output
`scale`	plus-minus 4	—	input
`match`	to-letter matching	—	input
`value`	—	—	output
`matchedGpa`	—	—	output
`tie`	—	—	output

Assumptions / Validity

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

Assumptions

Default plus/minus map uses A+=4.33 … F=0.
Percentage ranges are one common U.S. syllabus convention for the matched letter, not a function of the input GPA.
Linear 5.0 assumes a 5.0 numeric ceiling linearly mapped to 4.0. It is not a generic weighted→unweighted GPA conversion.
Nearest matching is an approximation algorithm, not a registrar rule for converting cumulative GPA back into a letter.

Example

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

GPA 3.50, plus/minus, nearest → A- (tie, higher letter)

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 · 6/6 declared partitions (plus-minus-nearest, floor, flat, linear5, to-gpa, invalid-domain)
Calculation version: 1.1.3
Verification: 16/16 calculation tests · 16/16 legacy golden · 0/0 legacy boundary
Production surface contract: 6/6
Versions: Calculation 1.1.3 · CVP protocol 1.0.0-proposed · Evidence 2026-09-29.release-truth-v1
Verification revision: 2026-09-29.release-truth-v1 · 2/2 property · digest ec136afa8532
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: 7/7 golden · 3/3 CVP boundary · 1/1 invalid · 2/2 property · 1/1 metamorphic · 1/1 cross-interface · 6/6 CVP contract
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.1.3 (workspace artifacts agree)
Review-policy tier: Engine tested — catalog token engine_tested; supplemental; not CVP status

This calculator CURRENT · Public schema 1.1.3 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 6/6.

curl -sS -X POST 'https://www.calculatorx.com/api/v1/calc/gpa-to-letter' \
  -H 'Content-Type: application/json' \
  -d '{"inputs":{"mode":"to-letter","scale":"plus-minus","match":"nearest","gpa":3.67},"calculation_version":"1.1.3"}'

{
  "inputs": {
    "mode": "to-letter",
    "scale": "plus-minus",
    "match": "nearest",
    "gpa": 3.67
  },
  "calculation_version": "1.1.3"
}

POST /api/v1/calc/gpa-to-letter. This is a POST calculate endpoint — do not GET it.

Full REST contract: REST API docs.

Tool id: gpa-to-letter
Engine: gpa-letter
REST: POST /api/v1/calc/gpa-to-letter
MCP: execute_calculation with capability_id: "education.gpa_letter"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.1.3)
Versioned output schema: Immutable pin (1.1.3)

Operations

Declared calculation modes for this capability.

to-letter
to-gpa

References

Human-readable sources plus CVP reference evidence classes.

Sources

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

Try with an agent

Inspect, then execute. Same engine as REST and the human calculator.

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":"education.gpa_letter"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientInfo":{"name":"calculatorx-docs-example","version":"1.0.0"},"io.modelcontextprotocol/clientCapabilities":{}}}}'

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: execute_calculation' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"execute_calculation","arguments":{"capability_id":"education.gpa_letter","inputs":{"mode":"to-letter","scale":"plus-minus","match":"nearest","gpa":3.67},"calculation_version":"1.1.3"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientInfo":{"name":"calculatorx-docs-example","version":"1.0.0"},"io.modelcontextprotocol/clientCapabilities":{}}}}'

Pin calculation_version (1.1.3) when the result must stay reproducible.

Inspect the trust tier and required assurance level before execution. Full protocol notes: MCP docs.