1. Habit
  2. Skills
  3. Effect skill
kitlangton · 2K installs

Effect skill
Runs by itself, Effect code changes.

Effect code follows v4 defaults.

Install the Effect skill and make it a habit: follow https://gethabit.dev/skills/kitlangton/effect.md

  1. 1Copy
  2. 2Paste into Claude Code, Codex or Cursor
  3. 3It runs by itself

2K installs352 starsMIT licenceSource on GitHub ↗

Effect

by kitlangton · 2K installs

The skill

The effect skill helps TypeScript developers build production apps with Effect v4: services, layers, schemas, config, schedules, caches, streams, HTTP clients and tests.

Only when you ask.

The habit

Effect code follows v4 defaults.

↻ Runs by itselfEffect code changes

How the habit works.
You don't have to.

Three questionsWhen does it start? How does it check its work? What does it remember?

01

It starts by itself

Effect code changes. Runs in GitHub Actions or Claude Code routine.

  • ↻ Effect code changes
  • pull_request touches files importing effect

02

It checks its work

tests and do-nots. If a check fails, it tells you.

  • ✓tests pass
  • ✓no as any or non-null assertions added
  • ✓no direct process.env reads in application logic
  • ✓no Effect.sleep added to tests

03

It remembers

effect review log. The next run reads it first: open issues and the pinned effect version.

loops/effect-v4-review-loop/run-log.md

One run, step by step.
Then it stops.

Stop ruleStops after one pull request per run.

  1. 01

    Check sources

    Read the nearest AGENTS.md and the pinned effect version first.

  2. 02

    Pick branches

    Read only the references the change touches, such as references/SCHEMA.md or references/TESTING.md.

  3. 03

    Check defaults

    Compare services, schemas, config, schedules and streams with the core defaults.

  4. 04

    Check do-nots

    Flag casts, Schema.Class defaults, blind Layer.mergeAll and hand-rolled caches.

  5. 05

    Run tests

    Run the tests and log findings.

What it may do.
Nothing more.

Safe by defaultIt writes only in its own folder and asks you before anything goes out.

Is it for you?
Use it when it fits.

Quick checkRead both lists. If the left one sounds like you, the Effect skill helps.

Use it when

  • ✓ You write Effect v4 services
  • ✓ You model data with Effect Schema
  • ✓ You test Effect code

Skip it when

  • – You are on Effect v3 with no upgrade plan
  • – You do not use Effect

Questions

Effect skill, answered.

What if my project has its own conventions?

The skill says established project conventions take precedence.

Does it cover v3?

It targets v4; references/V4_APIS.md helps when upgrading from v3.

How do I install the Effect skill?

Copy the prompt at the top into your agent. It installs the skill from kitlangton/skills and sets up the habit. Or run npx skills add kitlangton/skills --skill effect.

Is the Effect skill free?

Yes. It is published under MIT. Habit is free too.

Effect. Now as a habit.

Install the Effect skill and make it a habit: follow https://gethabit.dev/skills/kitlangton/effect.md

  • Free
  • No account
  • Undo in one line

All kitlangton skills →More code skills →

Works in

  • Claude Code
  • Codex
  • Cursor
  • ChatGPT
  • Claude app

Made by kitlangton, published under MIT. Habit links to the original and never changes it. Is this your skill?

Copying didn't work here. Select the line and copy it by hand.