Core Skills¶

Core Skills turn canonical principles into language-independent decision procedures. Choose a Skill to inspect its modes, conflicts, and review rules.

API and CompatibilityDefines intentional public surfaces, observable compatibility, deprecation, and migration policy.api-and-compatibility Abstraction and ReuseResolves duplication, reuse, extension points, and independent changeability from demonstrated evidence.abstraction-and-reuse Code Clarity and SimplicityGuides proportionate local structure, naming, explicitness, and simplicity without prescribing language syntax.code-clarity Contracts, Validation, Errors, and SecurityDefines trust boundaries, semantic parsing, invariant enforcement, failure behavior, and authority limits.contracts-and-errors Dependencies and Architecture BoundariesGoverns dependency direction, boundary placement, and proportionate isolation from volatile details.dependencies-and-boundaries Distributed ReliabilityDefines retry, duplication, ordering, timeout, partial-failure, and convergence semantics.distributed-reliability Engineering Review LensesApplies broad engineering laws as evidence-seeking review questions rather than universal prescriptions.engineering-review-lenses Modular and Object DesignDefines cohesive responsibilities, stable information boundaries, collaboration, and proportionate decomposition.modular-design Performance and Resource EfficiencyApplies measurable budgets and bounded resource policy without speculative optimization.performance-and-resources Safe Change and Legacy ModernizationControls change scope, behavioral preservation, historical investigation, compatibility, and authorized redesign.safe-change State and Side EffectsDefines state ownership, mutation scope, effect sequencing, and consistency semantics.state-and-side-effects Testing StrategySelects evidence-producing test levels, behavior focus, feedback loops, and change-appropriate verification.testing-strategy