npm Library Setup

What it does

When your agent uses it

• Setting up npm packages
• Configuring ESM
• TypeScript packages
• React component libraries

Example prompts

• “/npm-library-setup”

Requirements

• Node.js

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Initialize your package
2. 2Configure for ESM by adding "type": "module" to package.json
3. 3Install build and test tools
4. 4Create your source files in src/ and run npm run build

What it can do on your machine

Read from SKILL.md and the folder at commit 0b67a90. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships script files (TypeScript and JavaScript, from the files we listed), which the agent can run.

  Shell commands in SKILL.md call:

  • npm

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • github.com
  • vitest.dev

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

npm Library Setup loads about 1.1k tokens when it runs, and up to ~9.3k if it reads all its reference files. Until then it costs about 57 tokens; SKILL.md has 360 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~57

When it runs · the whole SKILL.md, loaded when a task matches

~1.1k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~9.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from vana-com/personal-server at commit 0b67a90, republished under its MIT licence (© vana-com). 360 words, ~1,084 tokens.

name

npm-library-setup

description

Comprehensive guidance on setting up npm libraries with package.json, with a preference for ES Modules (ESM). Use when setting up npm packages, configuring ESM, TypeScript packages, or React component libraries.

{
  "type": "module",
  "main": "./dist/index.js",
  "types": "./dist/index.d.ts",
  "exports": {
    ".": {
      "types": "./dist/index.d.ts",
      "default": "./dist/index.js"
    }
  },
  "scripts": {
    "build": "bunchee",
    "test": "vitest",
    "test:run": "vitest run"
  },
  "engines": {
    "node": ">=20"
  }
}

npm install -D typescript @types/node

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ESNext",
    "moduleResolution": "NodeNext",
    "declaration": true,
    "strict": true
  }
}

npm install -D react @types/react

{
  "peerDependencies": {
    "react": "*"
  }
}

// Named exports
export function greet(name) {
  return "Hello, " + name + "!";
}

// Default export
export default class MyLibrary {}

// Import
import { greet } from "./module.js";
import MyLibrary from "./MyLibrary.js";

my-package/
├── package.json
├── src/
│   ├── index.js         # or index.ts
│   └── helpers.js
├── dist/                # Build output
└── README.md

© vana-com, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 16 other files (references) in .agents/skills/npm-library-setup of vana-com/personal-server.

• SKILL.md
• examples/example-package/package.json
• examples/example-package/src/helpers.js
• examples/example-package/src/index.js
• examples/example-ts-package/package.json
• examples/example-ts-package/src/helpers.ts
• examples/example-ts-package/src/index.test.ts
• examples/example-ts-package/src/index.ts
• examples/example-ts-package/tsconfig.json
• references/guides/01-getting-started.md
• references/guides/02-package-json-config.md
• references/guides/03-esm-syntax.md
• references/guides/04-building-and-testing.md
• references/guides/05-best-practices.md
• … and 3 more

Open the folder on GitHubat commit 0b67a90