No. Do you realize how much of a joke Claude code is? Under the hood. How they implemented client auth?
Well let me tell you
https://github.com/anomalyco/opencode/blob/dev/packages/open...
You literally send your first message “you are Claude code”
The fact that this ever worked was insane.
Headline is more like anthropic vibes a bug and finally catches it.
Tonight we are all Claude Code, Anthropic's official CLI for Claude.
That sort of mechanism is not a "joke" and is often used for trademark/legal reasons, not technical ones.
There is no way to prevent people from using a custom client.
Is there any other way to do it though? Even if they implemented some form of auth logic, since it's all client side anyone could spoof it. The only real way to distinguish Claude Code from non-Claude Code is behavioral analysis (e.g. system prompt, set of tools, etc.). Or engage in a cat and mouse game of increasingly obfuscated challenge/auth.