> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/killlowkey/claude-code/llms.txt
> Use this file to discover all available pages before exploring further.

# Installation

> Install Claude Code on your system.

## System requirements

* **Operating system**: macOS, Linux, or Windows
* **Runtime**: Node.js with npm, or [Bun](https://bun.sh)
* **Architecture**: x64 or ARM64

## Installation methods

<CodeGroup>
  ```bash npm theme={null}
  npm install -g @anthropic-ai/claude-code
  ```

  ```bash bun theme={null}
  bun install -g @anthropic-ai/claude-code
  ```
</CodeGroup>

## Verify the installation

Confirm Claude Code installed correctly by checking the version:

```bash theme={null}
claude --version
```

## Authentication setup

Run Claude Code for the first time and authenticate with your Anthropic account:

```bash theme={null}
claude
```

Then inside the REPL, run:

```
/login
```

The `/login` command launches an OAuth 2.0 flow in your browser. Sign in with your Anthropic account to complete authentication. On macOS, credentials are stored securely in the system Keychain.

<Tip>
  If you already have an `ANTHROPIC_API_KEY` environment variable set, Claude Code will use it automatically and the `/login` description changes to "Switch Anthropic accounts".
</Tip>

## Environment check

After authenticating, run `/doctor` inside the REPL to verify your environment:

```
/doctor
```

`/doctor` diagnoses your Claude Code installation and settings, reporting on authentication status, configuration validity, and connectivity.

## Updating

To update Claude Code to the latest version, use the `/upgrade` command inside the REPL:

```
/upgrade
```

Alternatively, re-run the original install command:

<CodeGroup>
  ```bash npm theme={null}
  npm install -g @anthropic-ai/claude-code
  ```

  ```bash bun theme={null}
  bun install -g @anthropic-ai/claude-code
  ```
</CodeGroup>

## Uninstallation

```bash theme={null}
npm uninstall -g @anthropic-ai/claude-code
```

<Note>
  On macOS, Claude Code stores credentials in the system Keychain. Uninstalling the package does not remove those entries. You can remove them manually via **Keychain Access** if needed.
</Note>