effect-ts

name	effect-ts
description	Idiomatic Effect-TS patterns for the marimo-lsp extension. Use when writing or reviewing Effect code in `extension/src` — grounded in this repo's actual usage and citing into vendored Effect source at `repos/effect/`.

Effect-TS patterns (marimo-lsp)

This skill is an index. Each file in patterns/ is a short, code-heavy reference for one slice of the Effect API, with worked examples from extension/src and cites into repos/effect/packages/effect/src/.

Run just vendor-effect first if repos/effect/ is empty — the pattern files reference paths inside it.

When to read which file

Working on	Read
A new service or wiring MainLive	patterns/layers-services.md
A function in the Effect channel (entry point, span, log)	patterns/effect-core.md
Parsing data at a boundary (LSP, config, file)	patterns/schema.md
Typed domain errors / catchTag / Cause / Exit	patterns/data-errors.md
Consuming or producing a Stream (e.g. marimo/operation)	patterns/streams.md
Replacing a nullable type or Either flow	patterns/option-either.md
Holding state inside a service (Ref, SubscriptionRef, Deferred)	patterns/state.md
Writing a test (it.effect, TestClock, mocks)	patterns/testing.md

Conventions

Every pattern file follows the same shape: TL;DR, constructors/combinators table, worked examples from this repo, worked examples from Effect itself, error handling, and a "what to avoid" section. Code samples honor the repo conventions in CLAUDE.md (named Effect.fn, annotateLogs over interpolation, withSpan on external calls, no as T without // SAFETY:).

When a pattern file disagrees with repos/effect/ source, trust the source — file an issue or open a PR to fix the pattern doc.