Verified:GitHub

effect-service-implementation

Implement composable Effect v4 services with namespace modules and Layer.effect dependency wiring.

22|1|Updated Apr 14, 2026

Search Tags:#effect-ts #dependency injection #layer composition #service architecture #context service #capability design #testing with layers

One-click install

npx skills add https://github.com/mpsuesser/pi-effect-harness --skill effect-service-implementation

Or copy as Structured Prompt for Agent▼

Please help me install this Agent Skill.
Skill: effect-service-implementation
Source: https://github.com/mpsuesser/pi-effect-harness/tree/main/harnesses/effect/skills/effect-service-implementation
Command: npx skills add https://github.com/mpsuesser/pi-effect-harness --skill effect-service-implementation

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

It solves the problem of building large, monolithic or poorly separated Effect codebases by guiding you to implement each capability as a small, composable Effect service with clear dependency wiring.

Core Features & Use Cases

Namespace-module service structure: Keep Interface, Service tag, layer, and (optionally) defaultLayer together for an explicit service graph.
Dependency-safe construction: Use Layer.effect with captured dependencies via yield*, while ensuring service method Requirements stay as never (no requirement leakage).
Production composition by default: Build defaultLayer via Layer.provide so wiring is straightforward, testable, and maintainable.
Capability-based design: Split features into single-responsibility services like repositories, gateways, coordinators, and run-state.
Testing-friendly layers: Promote implementation details into layers so you can swap behavior using Layer.succeed or Layer.mock.

Quick Start

Implement your capability as a namespace that defines an Interface, an empty Context.Service tag, a layer built with Layer.effect and Effect.gen, and a defaultLayer that wires in dependencies with Layer.provide only when needed.

Frequently Asked Questions about effect-service-implementation

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I structure composable Effect services to avoid monolithic designs?▼

Prevent requirement leakage in Effect service method signatures by capturing dependencies with yield* inside Layer.effect and returning implementations via Service.of, ensuring method Requirements stay as never.

What is the best way to wire dependencies in Effect-ts service layers?▼

Split features into single-responsibility Effect services such as repositories, gateways, coordinators, and run-state to achieve capability-based design and maintain a clear, explicit service graph.

Can I swap Effect service implementations for testing without changing production code?▼

Use Effect.fn with namespace-prefixed span names when implementing Effect v4 services to maintain organized tracing and ensure proper service construction across coordinator-style lifecycle services.

Why do my Effect service method signatures leak requirements into the call site?▼

Effect service method signatures leak requirements when dependencies are not properly captured within Layer.effect using yield*, so ensure implementations are returned via Service.of to keep Requirements as never.