Yeah... you split tasks into consecutively smaller tasks until it's estimateable.

I'm not saying that can't be done, but taking a large task that hasn't been broken down needs, you guessed it, a powerful agent. that's your senior engineer who can figure out the rote parts, the medium parts, and the thorny parts.

the goal isn't to have an engineer do that. we should still be throwing powerful agents at a problem, they should just be delegating the work more efficiently.

throwing either an engineer or an agent at any unexplored work means you just have to delegate the most experienced resource to, or suffer the consequences.