Financial Semantics and Lineage

Definitions, reconciliation and evidence rules used throughout CoreFinOps.

CoreFinOps treats financial accuracy as a product control rather than a cosmetic reporting preference. Monetary values use exact decimal representations with explicit currency. All financial views must preserve the basis and source of their calculations.

Monetary identity

A useful financial number requires at least amount, currency, financial period, cost measure, scope, source and authority/freshness. The original v1 implementation stores precise money with PostgreSQL NUMERIC and uses a decimal arithmetic model in TypeScript.

Source versus projection

Actual AWS billing facts come from configured exports. Legacy source costs may be imported actuals or estimates. Target AWS run rates and payback are modeled projections. Different source classes must be labeled instead of being silently added as comparable observed actuals.

Authoritative allocation

Published allocation runs are versioned and immutable. For a comparable period/scope/currency/measure, Overview, Explorer, Reports and relevant economics should reconcile to that authority. New rules produce a new calculation, not retroactive rewriting of earlier published views.

Verification labels

Estimated opportunity, approved action, customer-attested implementation and system-measured saving have different evidentiary thresholds. Human verification must not be described as automatic cost measurement. Overlap handling must prevent counting multiple mutually exclusive opportunities as independent savings.

Never do these things

• Fabricate an FX conversion.
• Reconstruct historical cost categories from today's tags.
• Interpret a partial period as a complete one.
• Say “verified savings” without verifying the baseline and post-change evidence.