Another way to think about it:

For Anthropic to have the best version of this software, they'd have to simultaneously ... well, have the best version of the software, but also beat every other AI company at all subtasks (like: technical writing, diagramming, bug finding -- they'd need to have the unequivocal "best model" in all categories).

Surely their version is not going to allow you to e.g. invoke Codex or what have you as part of their stack.