# Install Effect Package

> Install @effect/* packages safely. Use whenever adding a new Effect ecosystem dependency.

- Skill: `mattpocock/install-effect-package` (Agent Skill)
- Install (CLI): `npx skillmds@latest add mattpocock/install-effect-package`
- Raw SKILL.md: https://api.skillmd.com/api/skills/mattpocock/install-effect-package/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: mattpocock (https://skillmd.com/u/mattpocock)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/mattpocock/install-effect-package

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## Installing Effect Ecosystem Packages

This repo uses **pnpm**. To add any `@effect/*` package:

```bash
pnpm add @effect/package-name
```

pnpm resolves peer dependencies without rewriting the rest of the lockfile, so it
does not suffer from the npm failure mode this skill originally guarded against
(npm's `--legacy-peer-deps` silently stripping existing `@effect/*` peers such as
`@effect/rpc`, `@effect/sql`, `@effect/experimental` and corrupting the lockfile).

If a new `@effect/*` package reports a peer-dependency conflict, install the
matching peer versions explicitly rather than forcing the tree — check
`pnpm why <package>` to see what is already resolved before adding.