Create production-ready Effect domain models using Schema.TaggedStruct for ADTs, Schema.Data for automatic equality, with comprehensive predicates, orders, guards, and match functions. Use when modeling domain entities, value objects, or any discriminated union types.
Write comprehensive tests using @effect/vitest for Effect code and vitest for pure functions. Use this skill when implementing tests for Effect-based applications, including services, layers, time-dependent effects, error handling, and property-based testing.
Implement typed error handling in Effect using Data.TaggedError, catchTag/catchTags, and recovery patterns. Use this skill when working with Effect error channels, handling expected failures, or designing error recovery strategies.
Design and compose Effect layers for clean dependency management
Use @effect/platform abstractions for cross-platform file I/O, process spawning, HTTP clients, and terminal operations. Apply this skill when writing code that interacts with the filesystem, spawns processes, makes HTTP requests, or performs console I/O to ensure portability across Node.js, Bun, and browser environments.
Build composable React components using Effect Atom for state management. Use this skill when implementing React UIs that avoid boolean props, embrace component composition, and integrate with Effect's reactive state system.
Master Effect Schema composition patterns including Schema.compose vs Schema.pipe, transformations, filters, and validation. Use this skill when working with complex schema compositions, multi-step transformations, or when you need to validate and transform data through multiple stages.
Implement the complete spec-driven development workflow from instructions through requirements, design, and implementation planning. Use this skill when starting new features or major refactorings that benefit from structured planning before coding.