`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.

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 or jsconfig.json file, depending on whether the entry point is a TypeScript file - an entry point, which defaults to index.ts unless any of index.{tsx, jsx, js, mts, mjs} exist or the package.json specifies a module or main field - a README.md file $BUN AGENT RULE DISABLED=1 : - a CLAUDE.md file when Claude CLI is detected disable with CLAUDE CODE AGENT RULE DISABLED env var - a .cursor/rules/ .mdc file when Cursor is detected, which tells Cursor AI https://cursor.sh to 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 CSS shadcn – 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