alt Hacker NewsFor my needs, Opus does these kind of "long horizon tasks" well enough already, with additional tooling.
As long as you are chunking out the tasks generated from the plan, you can manually (or write an orchestrator to...) give the component tasks to agents that pass along inputs and outputs per the dependency graph derived from the plan.
You can write this plan yourself or review it with the agent. Chunking tasks out of the plan like this has the added benefit of being able to swap for a different model when the time comes (looking forward to Opus-level models I can run on my consumer card...)
Not really convinced using Fable and trusting the harness to orchestrate for you is worth the intelligence upgrade. An understanding of an high level implementation plan of your task is also necessary when working with colleagues who rightfully quiz you. Especially since, at least for my work, there isn't a lot that Opus struggles with.
I've been chunking out my plans like this for months, and even maintain a port of Get-Shit-Done https://github.com/LoganDark/get-shit-done to the Jujutsu version control system because that was the best way for me to make the most of Opus.
I don't need that with Fable. I can give Fable a task of any complexity and it will spend over 8 hours in a single turn if it needs to. And then the task will be finished.
For example, Fable is far better at helping me keep that port updated with upstream's agentic pace of development. With Opus I would be spending all day working through each merge step by step. With Fable I can safely nap through it.
I don't know exactly how to communicate that difference other than that Fable just seems to make better decisions more consistently and more reliably to the point where I feel confident trusting it a lot more.