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CVP verified calculation capability

Critical depth Calculation Capability

Rectangular yc=(q²/g)^{1/3}. Not a Froude wrap, not specific energy, not a hydraulic jump, not Manning, not Q=Av.

Physics · Fluid Capability ID physics.fluid.critical_depth version 1.0.0 CVP VERIFIED CURRENT Engineering

Model

Critical depth

Modes: depth · unit discharge

Inputs / Outputs

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

SymbolQuantityUnitRole
qUnit discharge in m²/s—input / output
q_m2Unit discharge in m²/ssinput
QVolumetric discharge in m³/s—input / output
bRectangular width in m—input / output
ycCritical depth in m—input / output
gGravity in m/s²—input / output
vc——output
model——output

Assumptions / Validity

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

Assumptions

Not supported

Example

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

q=1 → yc=(1/g)^{1/3}

Open this example in the calculator

Trust

CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · Rectangular yc = (q²/g)^{1/3} with unit-discharge invert; + O3 mpmath tabulated yc.. 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 · Engineering assurance · Rectangular yc = (q²/g)^{1/3} with unit-discharge invert; + O3 mpmath tabulated yc.· View Manifest · CVP overview · Specification
Verified scope
Rectangular yc = (q²/g)^{1/3} with unit-discharge invert; + O3 mpmath tabulated yc.
Assurance
Engineering
Declared partition coverage
PASS · 5/5 declared partitions (depth, solve, alias, awkward, invalid-domain)
Deferred
Not trapezoid critical depth, not alternate depth, not Manning yn, and not Q=Av alone.
Calculation version
1.0.0
Verification
17/17 calculation tests · 2/2 legacy golden · 10/10 legacy boundary · 5/5 legacy property
Production surface contract
5/5
Versions
Calculation 1.0.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-26.o2-o3.iface
Verification revision
2026-09-26.o2-o3.iface · 1/1 property · digest 5c7c205b89d1
Reference
O1 model · O3 expected_values · O3 numerical_behavior · O2 expected_values · O2 numerical_behavior
Numerical scope
O2: yc=(q²/g)^{1/3} vs a separate-module identity (≤2 ULP). Not trapezoid critical depth, not alternate depth, not Manning, and not Q=Av alone. ≤2 ULP vs O3 applies only to the published tabulated critical-depth vectors. Not trapezoid yc, not Manning, and not alternate depth.
Interfaces
PASS · UI (SSR) / REST / MCP
ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
CVP suite
4/4 golden · 10/10 CVP boundary · 11/11 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 5/5 CVP contract
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)
Review-policy tier
Engine tested — catalog token engine_tested; supplemental; not CVP status
This calculator CURRENT · Public schema 1.0.0 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 5/5.

curl -sS -X POST 'https://www.calculatorx.com/api/v1/calc/critical-depth' \
  -H 'Content-Type: application/json' \
  -d '{"inputs":{"q":1},"calculation_version":"1.0.0"}'

POST /api/v1/calc/critical-depth. This is a POST calculate endpoint — do not GET it.

Full REST contract: REST API docs.

Tool id
critical-depth
Engine
critical-depth
REST
POST /api/v1/calc/critical-depth
MCP
execute_calculation with capability_id: "physics.fluid.critical_depth"
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

Reference evidence classes: O1 model · O3 expected_values · O3 numerical_behavior · 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":"physics.fluid.critical_depth"},"_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.