skill CX Codex

bun — Claude Code skill: what it does, how to install

Q: How to install bun in Claude Code?

Run `npx skills add brianlovin/agent-config --skill bun -a claude-code` in your terminal. The configuration is stored at `~/.claude/skills/bun/SKILL.md`.

Q: Does Bun need dotenv for environment variables?

No, Bun reads `.env` files automatically on startup. The skill explicitly prevents adding dotenv to your project.

Configures the assistant to use the Bun runtime instead of Node.js and npm. Replaces heavy npm packages with built-in APIs.

Install into Claude Code · Skills CLI (Vercel) All methods and platforms ↓

npx skills add brianlovin/agent-config --skill bun -a claude-code

Open on GitHub

What bun does

This skill redirects your coding agent to Bun conventions across the board. Instead of proposing npm run or ts-node, the model generates direct file execution via bun run, bun build, and bun test. It also stops installing dotenv, as Bun reads .env files natively.

Inside codebases, the agent picks native APIs over familiar Node packages. It swaps Express for Bun.serve(), replaces postgres clients with Bun.sql, and picks bun:sqlite instead of better-sqlite3. For frontend work with React, it configures HTML imports on Bun.serve() with --hot reload rather than Vite.

If your stack relies on packages without Bun equivalents, the agent push toward native APIs causes friction. For interface details, the skill points directly to node_modules/bun-types/docs/**.md.

What it helps with

migrate project commands from npm and Jest to Bun
spin up HTTP and WebSocket endpoints using Bun.serve without Express
query SQLite or PostgreSQL using built-in Bun drivers
serve React frontends via HTML imports instead of Vite

Example prompts for the agent

Write unit tests for the auth service using bun:test.
Set up a Bun.serve HTTP server that handles API routes and serves index.html with hot reload.
Run a shell command and read a local file using native Bun methods.

How to install bun

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill bun -a claude-code

2Manually: put the files in place

~/.claude/skills/bun/SKILL.md

Copy the whole skill folder; for one project use .claude/skills/bun/

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill bun -a codex

2Manually: put the files in place

.agents/skills/bun/SKILL.md

For all projects use ~/.agents/skills/

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill bun -a cursor

2Manually: put the files in place

.cursor/skills/bun/SKILL.md

Cursor also reads .agents/skills/ and .claude/skills/

1GitHub CLI

gh skill install brianlovin/agent-config bun

2Manually: put the files in place

.github/skills/bun/SKILL.md

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill bun -a gemini-cli

2Platform CLI

gemini skills install https://github.com/brianlovin/agent-config --path skills/bun

Manually: put the files in place

.devin/skills/bun/SKILL.md

The legacy .windsurf/skills/ path still works

Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill bun -a opencode

Step by step, with commands for each platform: How to install skills in Claude Code: five ways

Questions about bun

How to install bun in Claude Code?

Run npx skills add brianlovin/agent-config --skill bun -a claude-code in your terminal. The configuration is stored at ~/.claude/skills/bun/SKILL.md.

What does the bun skill do?

It instructs the assistant to rely on Bun commands and native runtime APIs instead of Node tools like dotenv, express, and vitest.

Does Bun need dotenv for environment variables?

No, Bun reads .env files automatically on startup. The skill explicitly prevents adding dotenv to your project.

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