This is odd behaviour, and provides some evidence that Anthropic isn't being managed by serious people. With this policy across AWS/GH/Zed/etc, they're taking their massive lead in enterprise/govt sales and handing it to any competitor who can serve a model anywhere near these capabilities with a modestly nice UI.
Every one of the competitors capable of a similar model have been salivating for a long time at the idea of consensual data sharing. Anthropic just opened the door for everyone to do the same thing without having to deal with being the first to do so. My bet is that OpenAI etc’s next model will have these same requirements. Ever since the Mythos announcement it’s been clear that we’re heading towards a future where S…
If the lift from these models is high enough and no alternative springs up, people will find a way to get to yes, but if OpenAI is willing to ship a Fable-class model on Bedrock without this, all the traffic will just move there. I say this because there is not much reason to use Bedrock unless you care about data sharing limits (ok, it seems more reliable than Anthropic's serving, but I don't think that's the major reason).
Of course, they could both decide they don't want the competitive advantage that having an AWS-controlled inference stack brings, but this is basically throwing out that advantage.
Note that this announcement is not just about Mythos, but also Fable, which is restricted from doing any Cyber work in the first place.