CVP verified calculation capability
USBR 1–8 ft Parshall free-flow Q from throat W and gage Ha, n=1.522 W_ft^{0.026}. Not thin-plate weir, not broad-crested weir, not Manning, not Q=Av, not orifice.
Physics · Fluid Capability ID physics.fluid.parshall_flume version 1.0.0 CVP VERIFIED CURRENT Engineering
USBR free flow
Q_cfs = 4 W_ft Ha_ft^nn = 1.522 W_ft^{0.026}Modes: flow · head
Canonical symbols for this capability. Agent schemas remain the contract.
| Symbol | Quantity | Unit | Role |
|---|---|---|---|
W | Throat width in m | — | input / output |
Ha | Specified-gage upstream head in m | — | input / output |
Q | Volume flow in m³/s | — | input / output |
n | — | — | output |
model | — | — | output |
Declared scope for this capability. Do not use it outside this domain.
Assumptions
Not supported
One numerical check. The calculator page holds worked steps and FAQ.
W=0.3048 Ha=0.3048 → Q≈0.11327
CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · USBR 1–8 ft Parshall free flow Q_cfs=4 W_ft Ha_ft^n, + O3 mpmath tabulated Q.. 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/parshall-flume' \
-H 'Content-Type: application/json' \
-d '{"inputs":{"W":0.3048,"Ha":0.3048},"calculation_version":"1.0.0"}'{
"inputs": {
"W": 0.3048,
"Ha": 0.3048
},
"calculation_version": "1.0.0"
}POST /api/v1/calc/parshall-flume. This is a POST calculate endpoint — do not GET it.
Full REST contract: REST API docs.
Human-readable sources plus CVP reference evidence classes.
Sources
Reference evidence classes: O1 model · O3 expected_values · O3 numerical_behavior · 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":"physics.fluid.parshall_flume"},"_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":"physics.fluid.parshall_flume","inputs":{"W":0.3048,"Ha":0.3048},"calculation_version":"1.0.0"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientInfo":{"name":"calculatorx-docs-example","version":"1.0.0"},"io.modelcontextprotocol/clientCapabilities":{}}}}'Pin calculation_version (1.0.0) when the result must stay reproducible.
Inspect the trust tier and required assurance level before execution. Full protocol notes: MCP docs.