It's complicated. A reply that's true enough and in the spirit of your original statement, is "Something going wrong with a sufficiently advanced AI that was intended as a 'tool' is mostly indistinguishable from something going wrong with a sufficiently advanced AI that was intended as an 'agent', because math-with-the-wrong-shape is math-with-the-wrong-shape no matter what sort of English labels like 'tool' or 'agent' you slap on it, and despite how it looks from outside using English, correctly shaping math for a 'tool' isn't much easier even if it "sounds safer" in English." That doesn't get into the real depths of the problem, but it's a start. I also don't mean to completely deny the existence of a safety differential - this is a complicated discussion, not a simple one - but I do mean to imply that if Marcus Hutter designs a 'tool' AI, it automatically kills him just like AIXI does, and Marcus Hutter is unusually smart rather than unusually stupid but still lacks the "Most math kills you, safe math is rare and hard" outlook that is implicitly denied by the idea that once you're trying to design a tool, safe math gets easier somehow. This is much the same problem as with the Oracle outlook - someone says something that sounds safe in English but the problem of correctly-shaped-math doesn't get very much easier.