CVP verified calculation capability
Solve any missing subtraction term with binary64, or exact non-negative decimal Long subtraction with borrowing up to48 aligned columns.
Math Capability ID math.subtraction version 1.0.2 CVP VERIFIED CURRENT Core
Difference
Minuend − Subtrahend = Differencea − b = a + (−b)If a + b = c then c − a = b and c − b = aModes: difference · long
Canonical symbols for this capability. Agent schemas remain the contract.
| Symbol | Quantity | Unit | Role |
|---|---|---|---|
minuend | — | — | input / output |
subtrahend | — | — | input / output |
difference | — | — | input |
review | — | — | output |
api_version | — | — | output |
api_contract_version | — | — | output |
spec_version | — | — | output |
page | Canonical calculator page URL | — | output |
links | — | — | output |
Inspectable numeric contract for this Capability@Version. Not a rewrite of the engine.
| Field | Declaration |
|---|---|
numeric_domain | real |
exactness | float64 |
algorithm | Shared binary64 missing-term subtraction/addition; Long uses bounded exact decimal digit borrowing |
valid_domain | Difference: exactly two decimal terms, all integral normalized operands safe. Long: nonnegative plain decimal strings up to48 aligned columns;512-character tokens; matching aliases; negative result allowed. |
singularity_policy | not applicable — No pole; overflow and nonzero text underflow rejected |
branch_policy | not applicable — real principal value only |
tolerance | not applicable — closed form; capability Evidence owns comparison, no global default |
convergence | not applicable — non-iterative |
conditioning | Near-equal subtraction may amplify relative input/conversion error. Measurement uncertainty is not modeled. |
rounding | Difference shortest round-trip binary64 display; Long display/exact_value exact decimal, numeric fields approximate. |
overflow | Finite results only; NUMERIC_UNDERFLOW/INTEGER_OUT_OF_SAFE_RANGE/INPUT_TOO_LONG/TOO_MANY_DIGITS reject outside the declared domain. |
reproducibility | deterministic algorithm + Capability@Version |
independent_oracle | Independent CPython Fraction / Decimal / scaled-integer complete packs in CVP math.subtraction |
golden_vectors | Evidence golden + boundary + property (and published_reference_case when listed) |
Declared scope for this capability. Do not use it outside this domain.
Assumptions
One numerical check. The calculator page holds worked steps and FAQ.
245 − 147 = 98
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.
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/subtraction' \
-H 'Content-Type: application/json' \
-d '{"inputs":{"mode":"difference","a":8,"b":3},"calculation_version":"1.0.2"}'{
"inputs": {
"mode": "difference",
"a": 8,
"b": 3
},
"calculation_version": "1.0.2"
}POST /api/v1/calc/subtraction. This is a POST calculate endpoint — do not GET it.
Full REST contract: REST API docs.
Declared calculation modes for this capability.
differencelongHuman-readable sources plus CVP reference evidence classes.
Sources
Derived identities
Reference evidence classes: O1 model · O2 expected_values · O2 numerical_behavior
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":"math.subtraction"},"_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":"math.subtraction","inputs":{"mode":"difference","a":8,"b":3},"calculation_version":"1.0.2"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientInfo":{"name":"calculatorx-docs-example","version":"1.0.0"},"io.modelcontextprotocol/clientCapabilities":{}}}}'Pin calculation_version (1.0.2) when the result must stay reproducible.
Inspect the trust tier and required assurance level before execution. Full protocol notes: MCP docs.