phoenix-precision-guard

Numeric drift in financial calculations occurs when floating-point arithmetic accumulates rounding errors. This Skill prevents drift by enforcing Decimal.js usage across critical P0 calculation paths, replacing parseFloat with precise decimal operations, and adding validation tests to ensure calculations maintain accuracy throughout your VC fund model.

Decimal.js provides arbitrary-precision arithmetic that preserves exact decimal values, whereas parseFloat converts strings to binary floats that introduce rounding errors. This Skill enforces Decimal.js configuration centrally and removes parseFloat from P0 paths to eliminate compounding precision loss in financial calculations.

Type safety in financial code catches precision errors at compile time. This Skill configures incremental TypeScript strictness (noImplicitAny, strictNullChecks, strictFunctionTypes, noImplicitReturns) and sets ESLint rules to enforce explicit radix for parseInt, preventing implicit type coercion in numeric operations.

Precision testing validates that calculations maintain accuracy after refactoring. This Skill adds precision-focused tests across server analytics and client engines, preserves truth-case baselines after decimal conversions, and enforces Decimal.js validation to ensure all P0 paths produce auditable results.

Yes. This Skill enables incremental TypeScript strictness and triages parseFloat occurrences rather than forcing a rewrite. You configure ESLint and TypeScript gradually, validate Decimal.js usage in P0 paths first, and preserve existing test baselines to maintain stability during the transition.

This Skill eliminates errors from floating-point rounding and implicit type coercion in P0 calculation paths through Decimal.js enforcement and type checking. It does not address logic errors or domain-specific validation rules, which require separate review and testing.