The HuggingFace hack isn't OpenAI's responsibility because they hosted it. It's their responsibility because they directed it; it was part of their own internal benchmark run that they fully controlled.

If a third party uses a model created and hosted by OpenAI, I don't think OpenAI should be liable so long as they implement acceptable security controls. Same as if a site hosted on Cloudflare or GCP is doing something dodgy, Cloudflare/GCP aren't held liable so long as they respond to abuse reports.

To the extent they are representing that Claude is potentially sentient, there could be some VERY interesting principal-agent theories (agent in the traditional legal sense) that need to be ironed out to determine liability. It would not shock me to see someone forced to answer on the record as to whether Claude is an autonomous individual for legal purposes in the next couple of years. If they represent that it is, they'll have to explain the scope of its authority and such.

The answer to this question represents the difference between throwing a hammer at someone - the hammer is essentially just an extension of your body - and paying a hitman to brutalize someone. In the first case, you're only on the hook for assault or battery; in the latter case, you're potentially on the hook for conspiracy, solicitation, etc.

And then there is of course the question as to whether Claude is the agent of the user prompting it or of Anthropic itself. But, as you say, this is a wide-open legal question.

Not hosting a defectively designed product doesn't obviate the liability of selling a product that is defectively designed. The liability is for designing and selling a dangerous product, not for hosting it.