That is old. Every harness (herdr, paseo, pi, etc) uses claude through the Agent SDK, and this draws from your subscription, not API pricing. If you're thinking of going with the "but Anthropic could ban every user doing this", if it's good enough for Google to slap it in Android Studio for everyone to use, it's good enough for you in literally any other harness.
Herdr is a harness aware terminal multiplexer, not a harness itself.
If paseo and herdr are harnesses then so are tmux and iTerm
I dont think you know what a harness is.
Google has an agreement with Anthropic for the usage inside Android Studio.
> Unless previously approved, Anthropic does not allow third party developers to offer claude.ai login [..] for their products.
ref: https://code.claude.com/docs/en/agent-sdk.md
Yes there is a huge gray area. Yes people are getting away with it. That does not mean it's allowed. Anthropic could clarify their terms any day and they don't, on purpose.