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name: effect-lookup description: Quick lookup for Effect TypeScript library APIs, patterns, and source code. Use when you need to find Effect functions, understand Effect patterns, or look up implementation details.

Effect Library Lookup

Quick reference for finding and understanding Effect TypeScript library APIs from the local git subtree at docs/effect/.

When to Use This Skill

Use this skill when:

• Looking up Effect function signatures or implementations
• Finding examples of Effect patterns (Effect.gen, Layer, Context, etc.)
• Understanding how Effect modules work internally
• Checking API availability or deprecation status
• Learning Effect idioms from source code

How to Look Up Effect APIs

1. Use the Effect Docs MCP Server (Fastest)

The effect-docs MCP server provides indexed documentation:

Copymcp__effect-docs__effect_docs_search: Search for Effect concepts
mcp__effect-docs__get_effect_doc: Get specific documentation by ID

2. Search the Git Subtree Source

For implementation details, search the local source at docs/effect/:

Copy# Find a specific function
grep -r "export const myFunction" docs/effect/packages/effect/src/

# Find usage patterns
grep -rn "Effect.gen" docs/effect/packages/effect/src/

# Find type definitions
grep -rn "interface MyType" docs/effect/packages/effect/src/

3. Read Source Files Directly

Core modules are at: docs/effect/packages/effect/src/<Module>.ts

Example: To understand Effect.map, read docs/effect/packages/effect/src/Effect.ts

Quick Reference

Package Structure

Copydocs/effect/
├── packages/
│   ├── effect/               # Core Effect library
│   │   └── src/              # Source files (Effect.ts, Layer.ts, etc.)
│   ├── platform/             # Cross-platform utilities (HTTP, FileSystem)
│   ├── platform-node/        # Node.js platform implementation
│   ├── platform-browser/     # Browser platform implementation
│   ├── cli/                  # CLI building utilities
│   ├── sql/                  # SQL database utilities
│   ├── sql-pg/               # PostgreSQL implementation
│   ├── sql-kysely/           # Kysely integration
│   ├── rpc/                  # Remote procedure calls
│   ├── cluster/              # Distributed computing
│   ├── opentelemetry/        # OpenTelemetry integration
│   ├── experimental/         # Experimental features
│   └── ai/                   # AI integrations (OpenAI, Anthropic, etc.)

Core Modules Quick Lookup

Effect System

Data Types

Concurrency

Schema & Validation

Streaming

Scheduling & Time

Configuration

Common Lookup Patterns

Find Function Signature

Copy# In Effect.ts, functions are well-documented with JSDoc
grep -A 20 "export const map" docs/effect/packages/effect/src/Effect.ts

Find Type Definition

Copy# Look for interface or type alias
grep -n "interface Effect<" docs/effect/packages/effect/src/Effect.ts

Find Examples in Tests

Copy# Tests often have practical examples
grep -rn "Effect.gen" docs/effect/packages/effect/test/

Check Platform APIs

Copy# HTTP client/server
ls docs/effect/packages/platform/src/Http*.ts

# FileSystem
cat docs/effect/packages/platform/src/FileSystem.ts

External References

• Effect Website - Official documentation
• Effect API Reference - Full API docs
• Effect Discord - Community support

Tips for Effective Lookups

1. Start with MCP search - Use effect_docs_search for conceptual questions
2. Read JSDoc comments - Effect source has excellent inline documentation
3. Check tests for examples - Test files show real usage patterns
4. Use module tables above - Quickly navigate to the right source file
5. Platform packages - HTTP, FileSystem, etc. are in @effect/platform