Install Claude Code with npm when the install script fails

The official install command is:

curl -fsSL https://claude.ai/install.sh | bash

On Windows PowerShell it is irm https://claude.ai/install.ps1 | iex. Both scripts first ask downloads.claude.ai for the latest version number. When that fails they stop with:

Failed to get a valid version from downloads.claude.ai (got unexpected content).

The next line says the download service is unreachable or not available in your region. If claude.ai itself is blocked, the script cannot be downloaded at all. In either case, install from npm as below.

The npm package of Claude Code requires Node.js 22 or newer. Check your version:

node --version

If Node.js is missing or older than 22, install the LTS release from nodejs.org. In mainland China the npmmirror mirror has the same installers at https://npmmirror.com/mirrors/node/ and is usually faster.

Run this in a terminal on macOS or Linux, or in PowerShell or Command Prompt on Windows:

npm install -g @anthropic-ai/claude-code

In mainland China, use the npmmirror registry:

npm install -g @anthropic-ai/claude-code --registry=https://registry.npmmirror.com

Then check that it works:

claude --version

If you see a version number, Claude Code is installed. The npm package pulls in the build for your system as a separate npm package, so it comes from the same registry and never from downloads.claude.ai.

Run the install command again with @latest:

npm install -g @anthropic-ai/claude-code@latest --registry=https://registry.npmmirror.com

To stop typing --registry every time, make the mirror npm's default registry. This applies to every npm install on the computer:

npm config set registry https://registry.npmmirror.com

Claude Code also updates itself. To turn that off and choose when to upgrade, set the environment variable DISABLE_AUTOUPDATER=1.

Anthropic does not serve mainland China, so there you connect Claude Code with an API key and a base URL rather than a claude.ai login. The settings are in Connect Claude Code to your API key. If it fails, look up the message in Claude Code API errors.