majiayu000 Effect Library Lookup
Quick reference for finding and understanding Effect TypeScript library APIs from local source code.
Source Code Access
Source code is available locally and on GitHub. Check local first, fall back to GitHub if not available.
| Repo | Local path | GitHub |
|---|---|---|
| Effect | opensrc/repos/github.com/effect-ts/effect/ |
https://github.com/effect-ts/effect |
| EffectPatterns | opensrc/repos/github.com/PaulJPhilp/EffectPatterns/ |
https://github.com/PaulJPhilp/EffectPatterns |
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:
mcp__effect-docs__effect_docs_search: Search for Effect concepts
mcp__effect-docs__get_effect_doc: Get specific documentation by ID
2. Search the Local Source
For implementation details, search the local source at opensrc/repos/github.com/effect-ts/effect/:
# Find a specific function
grep -r "export const myFunction" opensrc/repos/github.com/effect-ts/effect/packages/effect/src/
# Find usage patterns
grep -rn "Effect.gen" opensrc/repos/github.com/effect-ts/effect/packages/effect/src/
# Find type definitions
grep -rn "interface MyType" opensrc/repos/github.com/effect-ts/effect/packages/effect/src/
3. Read Source Files Directly
Core modules are at: opensrc/repos/github.com/effect-ts/effect/packages/effect/src/<Module>.ts
Example: To understand Effect.map, read opensrc/repos/github.com/effect-ts/effect/packages/effect/src/Effect.ts
Quick Reference
| Task | Reference |
|---|---|
| Module categories | references/modules.md |
| Common patterns | references/patterns.md |
Package Structure
opensrc/repos/github.com/effect-ts/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
| Module | File | Purpose |
|---|---|---|
| Effect | Effect.ts |
Core effect type and combinators |
| Layer | Layer.ts |
Dependency injection layers |
| Context | Context.ts |
Type-safe service context |
| Scope | Scope.ts |
Resource management |
| Runtime | Runtime.ts |
Effect execution |
Data Types
| Module | File | Purpose |
|---|---|---|
| Option | Option.ts |
Optional values |
| Either | Either.ts |
Success/failure values |
| Chunk | Chunk.ts |
Immutable arrays |
| HashMap | HashMap.ts |
Immutable hash maps |
| HashSet | HashSet.ts |
Immutable hash sets |
| List | List.ts |
Immutable linked lists |
Concurrency
| Module | File | Purpose |
|---|---|---|
| Fiber | Fiber.ts |
Lightweight threads |
| Queue | Queue.ts |
Concurrent queues |
| Ref | Ref.ts |
Mutable references |
| Semaphore | Semaphore.ts |
Concurrency limiting |
| PubSub | PubSub.ts |
Publish/subscribe |
Schema & Validation
| Module | File | Purpose |
|---|---|---|
| Schema | Schema.ts |
Data validation & encoding |
| ParseResult | ParseResult.ts |
Parsing results |
| Arbitrary | Arbitrary.ts |
Property-based testing |
Streaming
| Module | File | Purpose |
|---|---|---|
| Stream | Stream.ts |
Effectful streams |
| Sink | Sink.ts |
Stream consumers |
| Channel | Channel.ts |
Bidirectional streaming |
Scheduling & Time
| Module | File | Purpose |
|---|---|---|
| Schedule | Schedule.ts |
Retry/repeat schedules |
| Duration | Duration.ts |
Time durations |
| DateTime | DateTime.ts |
Date/time handling |
| Clock | Clock.ts |
Time service |
| Cron | Cron.ts |
Cron expressions |
Configuration
| Module | File | Purpose |
|---|---|---|
| Config | Config.ts |
Type-safe configuration |
| ConfigProvider | ConfigProvider.ts |
Configuration sources |
Common Lookup Patterns
Find Function Signature
# In Effect.ts, functions are well-documented with JSDoc
grep -A 20 "export const map" opensrc/repos/github.com/effect-ts/effect/packages/effect/src/Effect.ts
Find Type Definition
# Look for interface or type alias
grep -n "interface Effect<" opensrc/repos/github.com/effect-ts/effect/packages/effect/src/Effect.ts
Find Examples in Tests
# Tests often have practical examples
grep -rn "Effect.gen" opensrc/repos/github.com/effect-ts/effect/packages/effect/test/
Check Platform APIs
# HTTP client/server
ls opensrc/repos/github.com/effect-ts/effect/packages/platform/src/Http*.ts
# FileSystem
cat opensrc/repos/github.com/effect-ts/effect/packages/platform/src/FileSystem.ts
EffectPatterns Knowledge Base
Community-driven patterns and architectural guides at opensrc/repos/github.com/PaulJPhilp/EffectPatterns/.
# Browse pattern categories
ls opensrc/repos/github.com/PaulJPhilp/EffectPatterns/content/
# Search for a specific pattern
grep -rn "Layer" opensrc/repos/github.com/PaulJPhilp/EffectPatterns/content/
# Read docs
ls opensrc/repos/github.com/PaulJPhilp/EffectPatterns/docs/
Covers: getting started, core concepts, error management, resource management, concurrency, streams, scheduling, domain modeling, schema, platform, HTTP APIs, data pipelines, testing, and observability.
External References
- Effect Website - Official documentation
- Effect API Reference - Full API docs
- Effect Discord - Community support
Tips for Effective Lookups
- Start with MCP search - Use
effect_docs_searchfor conceptual questions - Read JSDoc comments - Effect source has excellent inline documentation
- Check tests for examples - Test files show real usage patterns
- Use module tables above - Quickly navigate to the right source file
- Platform packages - HTTP, FileSystem, etc. are in
@effect/platform - EffectPatterns - Use for architectural patterns and best practices