Quick Answer
Grok is the least filtered among major AI models. Claude and ChatGPT are the most cautious.
Detailed Answer
Grok was explicitly designed with fewer content restrictions and will discuss topics other AIs refuse. DeepSeek is also relatively permissive. ChatGPT sits in the middle with a balanced approach. Claude is the most conservative due to Anthropic's Constitutional AI safety framework. Note that "least censored" does not mean "best." Stricter safety filters often correlate with more reliable, less harmful outputs for professional use.
Find Your Own Answer
The best way to decide is to try them yourself. Council lets you compare multiple AI responses to the same question.