Status: accepted

Accepted — merged with intent to implement.

RFC 0125: Verify data-center purchase price per stated rentable square foot

Resolution

The UWMD maintainers accepted this contract on 2026-10-22. D1–D5 stand as written; the synchronized current contract is implemented.

Summary

Extend the existing price_per_sqft dictionary definition to data_center, using only explicit property.rentable_square_feet. Keep commissioned critical IT kW as primary size. D1–D5 define the accepted contract.

Motivation

The Mesa-Gateway example states rentable area and valuation.price_per_sf, but the current dictionary makes price_per_sqft applicable only to office, retail and industrial. RFC 0099's existing aliases therefore do not check that figure for data centers. Tampering it does not produce a stated-metric disagreement. The example also calls rentable area a building footprint/fallback and calls the builtin commissioned-kW metric a module. This PR corrects those narrative claims without changing numbers or authoring an unstated measurement standard.

Proposed change

A Verifier MUST select this entry for data_center:

{
  "id": "price_per_sqft",
  "asset_classes": ["data_center"],
  "formula": "valuation.purchase_price / property.rentable_square_feet",
  "input_paths": ["valuation.purchase_price", "property.rentable_square_feet"],
  "section_roles": {},
  "unit": "$",
  "round_to": 2,
  "minimum_stated_decimals": 2,
  "null_semantics": "positive_size_denominator",
  "deterministic": true
}

This is the office/industrial definition and comparison contract, applied to one additional class. Use the existing label Price / SqFt. RFC 0099's existing canonical homes, quick_metrics.price_per_sqft, valuation.price_per_sf and valuation.purchase_price_per_sqft all bind the same metric. Check every stated home and current variant separately. Retain Protocol VIII.2 section selection; ambiguous or unavailable inputs are unverifiable, never selected by fence order.

The denominator MUST be the explicitly stated rentable area. Do not substitute building footprint, raised-floor area, gross area, or a quantity inferred from kW, rack counts, power density or another class. Missing/null area yields an unverifiable statement; zero division retains its calc refusal; a negative size retains RFC 0100's negative_size_denominator outcome and Format SIZE-01.

Recompute unrounded in binary64 and compare once under RFC 0079 / Protocol VIII.5.1 at two decimals, half away from zero, with no epsilon. A finite mismatch is failed. Lack of source precision retains existing refusal behavior. The optional property.area_measurement declaration (RFC 0114) retains its current meaning; no area conversion or new required measurement declaration.

Register rentable_square_feet in the data-center size entry's secondary array, mirrored by SIZE_INTENSIVES and the property-size description. Current main's data-center secondary array is empty; this explicit registry addition is required so RFC 0100's denominator lookup recognizes the new SF metric. The field is already in the class-independent Format 5.5 SIZE-01 table; add no new size finding or mandatory area requirement.

The primary-size path stays property.critical_it_load_kw. Neither price_per_kw, price_per_commissioned_kw nor their existing consistency checks changes. No land or other-class entry changes.

Decisions for acceptance

#	Question	Recommendation	Precedent
D1	Denominator	Explicit property.rentable_square_feet only	Office/industrial price_per_sqft; owner fifth set
D2	Binding	Existing price_per_sqft id and closed aliases	RFC 0099, no label inference
D3	Precision/null	$; round_to 2; minimum 2; positive_size_denominator	RFCs 0079/0100; same SF definition
D4	Size registry	Keep commissioned critical IT kW primary; add rentable_square_feet as an explicit secondary	RFC 0080 primary identity; RFC 0100 denominator lookup needs a registered size
D5	Example	Describe stated rentable SF as secondary; builtin commissioned kW remains primary; no numeric edits	Accepted wording correction; RFC 0114

Current contract and versions

The synchronized spec/dictionary/pack and conformance changes implement the accepted contract. No version is allocated; prelaunch packages remain 4.x under the prelaunch policy. No historical artifact repair or compatibility path.

Conformance impact

Add portable metric cases for correct/wrong SF statements, all existing homes, agreeing quick metric with disagreeing section copy, missing/null/zero/negative area, ambiguous property/valuation selection, and distinct current variants. Prove secondary-registry parity and negative rentable area are guarded. kW-only inputs never supply missing area; changing kW alone does not change this SF metric. Keep existing primary-size and kW controls unchanged. Include cent-boundary and source-precision controls under the existing quantizer.

Reference implementation

This implementation synchronizes Format property/valuation text, Protocol metric contract and executable mirror/descriptions, dictionary, generated dictionary, data-center builtin pack and Excel output/parity, independent Python calculation controls, metric conformance, size registry/SIZE_INTENSIVES secondary-path parity, wiki and changelog in one implementation PR. Update current counts from actual dictionary contents. No new API or external dependency.

Alternatives considered

Use price_per_kw only: leaves an explicitly stated SF price unverified. Infer SF from power: invents a financial input and conflates distinct measurements. Add a data-center-only id: needlessly duplicates the identical rentable-SF rule.

Unresolved questions

D1–D5 are accepted. No further formula or tolerance is delegated to the implementer. Implementation evidence follows the synchronized contract.

Prior art

RFCs 0078/0079 define dictionary meaning and precision; RFCs 0099/0100 define closed statement homes and positive-size denominators. RFC 0114 records optional measurement standards without conversions.