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[ARTICLE · art-77565] src=bun.com ↗ pub= topic=developer-tools verified=true sentiment=· neutral

`bun init` automatically creates a Claude.md file by default

Bun's `bun init` command now automatically creates a CLAUDE.md file by default when Claude CLI is detected, and a `.cursor/rules/*.mdc` file when Cursor is detected, to configure AI tools for the project. The feature can be disabled with the `CLAUDE_CODE_AGENT_RULE_DISABLED` environment variable. Bun also scaffolds a `package.json`, `tsconfig.json` or `jsconfig.json`, an entry point, and a `README.md` file, with optional React project templates.

read1 min views1 publishedJul 28, 2026
`bun init` automatically creates a Claude.md file by default
Image: Bun Blog

bun init

. terminal

enter

to accept the default answer for each prompt, or pass the -y

flag to auto-accept the defaults. bun init

infers settings with sane defaults and is non-destructive when run multiple times.

  • a package.json

file with a name that defaults to the current directory name - a tsconfig.json

orjsconfig.json

file, depending on whether the entry point is a TypeScript file - an entry point, which defaults to index.ts

unless any ofindex.{tsx, jsx, js, mts, mjs}

exist or thepackage.json

specifies amodule

ormain

field - a README.md

file

$BUN_AGENT_RULE_DISABLED=1

):

  • a CLAUDE.md

file when Claude CLI is detected (disable withCLAUDE_CODE_AGENT_RULE_DISABLED

env var) - a .cursor/rules/*.mdc

file when Cursor is detected, which tellsCursor AIto use Bun instead of Node.js and npm

-y

or --yes

to accept the defaults without prompting. At the end, it runs bun install

to install @types/bun

.

CLI Usage #

terminal

Initialization Options

boolean

Accept all default prompts without asking questions. Alias:

-y

boolean

Only initialize type definitions (skip app scaffolding). Alias:

-m

Project Templates

string|boolean

Scaffold a React project. When used without a value, creates a baseline React app.

Accepts values for presets:

Accepts values for presets:

tailwind

– React app preconfigured with Tailwind CSSshadcn

– React app with@shadcn/ui

and Tailwind CSS

bun init —react bun init —react=tailwind bun init —react=shadcn

Output & Files

info

Initializes project files and configuration for the chosen options. Exact files vary by template.

Help

boolean

Print this help menu. Alias:

-h

Examples

Accept all defaults terminal #

React terminal #

React + Tailwind CSS terminal #

React + @shadcn/ui terminal

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