Effect-TS Skills
Official Effect skills that point the agent to the guide in node_modules and drive a project migration from version 3 to 4.
- 115 ★ on the repository
- Last commit
- MIT
Extended access
Why this level
- The migration skill edits `package.json` and many source files, and the effect-ts skill appends to AGENTS.md or CLAUDE.md.
- Migration clones Effect repositories into `.repos/effect` and needs network access.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add skills/effect-ts-skillsDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The migration skill edits `package.json` and many source files, and the effect-ts skill appends to AGENTS.md or CLAUDE.md.
- Migration clones Effect repositories into `.repos/effect` and needs network access.
This is third-party code. Review the repository files before installing.
What it does
The repository holds two skills. The effect-ts skill prepares a project on Effect: it installs the `effect` package with the project's package manager and adds to AGENTS.md or CLAUDE.md a requirement to read `node_modules/effect/AGENTS.md` completely before writing code. When the guide does not answer a question, the agent searches the sources in `node_modules/effect/src`. The effect-v3-to-v4 skill drives an upgrade from version 3 to 4 using the generated reference `migration/v3-to-v4.md` from the Effect repository. It takes two shallow clones of the v4 and v3 branches, updates `package.json`, runs the type check and fixes errors one by one, finding replacements in the reference rather than guessing. The model does not invoke it by itself: you must start it manually.
Who it is for. TypeScript teams on Effect whose agents write code from outdated habits and get the API wrong.
Good fit when
- The agent enters an Effect repository for the first time and must write for the installed version.
- A project moves from Effect v3 to v4 and a flood of type errors must be sorted out.
- CLAUDE.md needs a permanent line sending the agent to the package guide.
- The migration is split by file and fixes are handed to subagents one error at a time.
Not a fit when
- The project does not use Effect.
- You want a general Effect reference for manual reading: the skill only directs the agent.
- The upgrade runs between versions other than 3 and 4.
Example request
Prepare this repository for Effect work, then start the migration from version 3 to 4 with the effect-v3-to-v4 skill.Limitations
The effect-ts skill relies on the `node_modules/effect/AGENTS.md` file, so the `effect` package must be installed, and in a monorepo it goes to the root as a dev dependency so the sources are reachable. The migration skill needs network access for two shallow clones of the Effect repository in `.repos/effect` and verifies an existing copy before trusting it. It edits `package.json`, consolidates packages and aligns versions, and it reports test results as they are but does not treat them as a completion gate. The migration skill forbids silencing type errors. The reference is searched, not read whole.
How to disable. Delete the effect-ts and effect-v3-to-v4 folders from the agent skills directory and revert the AGENTS.md or CLAUDE.md lines. Copies in `.repos/effect` are removed separately.
FAQ
How do I install the Effect skills in Claude Code?
Run `npx skills add Effect-TS/skills`. The installer places effect-ts and effect-v3-to-v4 in the agent skills directory.
How does the effect-ts skill differ from the guide in the package?
The guide lives in `node_modules/effect/AGENTS.md`, while the skill makes the agent read it before writing code and records this in the project AGENTS.md.
Why does the migration not start by itself?
Model invocation is disabled in the effect-v3-to-v4 skill. Start it with an explicit command when the project is ready to upgrade.
Where does the skill take migration rules from?
From the `migration/v3-to-v4.md` reference in the Effect repository. All replacements are searched there, and when data is missing it escalates to topic guides and v4 and v3 sources.
Can the skill be used with Cursor or Codex?
The `npx skills` installer targets agents following the Agent Skills standard, so those fit too.
Discussion
No questions or reviews yet.
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