I have purchased tier 3 and I am facing the same problem highlighted in an earlier question by fastandcurious. In the LLM settings, I am trying to use Claude; I have entered the API key and, from the link you provided, selected the model name : claude-sonnet-4-6

However, the system does not pick it up, and I am getting the same error that Fast and Curious pointed out earlier, two or three messages below mine.

Edit: Just tried deepseek API and it faces same problem as claude. In both cases, the bot replies with this to any query: ⛔ An error occurred while generating a response: Model Not Exist

PS: In my testing, I used OpenRouter without any issue.