Effect Skill Index

Use this as a quick router to the right Skill for your task. Each entry links to a focused Skill optimized for a coding agent’s limited context.

Decision Tree

• I need to write or refactor some Effect code → Foundations

• I need robust error handling/retries → Errors & Retries

• I must run things in parallel / manage fibers → Concurrency & Fibers

• This is a data pipeline / batching / backpressure → Streams & Pipelines

• I need DI/services/layers or test/live wiring → Layers & Services

• Opening files/sockets/servers with cleanup → Resources & Scope

• Add HTTP endpoints / JSON responses → HTTP & Routing

• Validate inputs / parse config → Config & Schema

• Value-based equality / high-perf immutable collections → Data Structures

• Time, logging, spans/tracing → Time/Tracing/Logging

• Queues, PubSub, background workers → Queues & Background

• Write tests/mocks for services → Testing & Mocking

• Looking for specific patterns or examples → Patterns Hub (130+ patterns)

Cross-Skill Patterns

All patterns are now available locally in the Patterns Hub (130+ patterns):

• Retry transient failures → Errors & Retries + retry-based-on-specific-errors.mdx

• Resource-safe streaming → Streams & Pipelines + stream-manage-resources.mdx

• Graceful shutdown → Queues & Background + execute-long-running-apps-with-runfork.mdx

• Service layer design → Layers & Services + model-dependencies-as-services.mdx

• HTTP server setup → HTTP & Routing + build-a-basic-http-server.mdx

• Schema validation → Config & Schema + define-contracts-with-schema.mdx

• Testing with mocks → Testing & Mocking + mocking-dependencies-in-tests.mdx

Tip: For any "How do I...?" question, check the Patterns Hub decision tree first!

Local Source Reference

CRITICAL: Always search local Effect source before implementing

The full Effect source code is available at docs/effect-source/ . Every Effect skill now includes a "Local Source Reference" section with:

• Key source files for that skill's domain

• Example grep commands to find implementations

• Workflow for searching before coding

Quick Access to Source

• All Effect packages: docs/effect-source/

• Core library: docs/effect-source/effect/src/

• Platform APIs: docs/effect-source/platform/src/

• SQL: docs/effect-source/sql/src/

• Schema: docs/effect-source/schema/src/

Example: Finding Effect.gen

grep -F "Effect.gen" docs/effect-source/effect/src/Effect.ts

Workflow Reminder

• Read the relevant skill (from decision tree above)

• Review the skill's "Local Source Reference" section

• Search the Effect source code for the API you need

• Study the implementation and types

• Write your code based on real implementations

See CLAUDE.local.md for complete source reference guide

References

• Agent Skills overview: Introducing Agent Skills

• Skills guide: Claude Code Skills Documentation

• Local Patterns Hub: ../effect-patterns-hub/SKILL.md (130+ patterns)

• Pattern Documentation: ../../docs/effect-patterns/

• AGENTS.md: ../../AGENTS.md (Effect best practices for AI agents)

• EffectPatterns (upstream source): PaulJPhilp/EffectPatterns