Fable 5 is the smartest AI ever made, and for the next few days you can use it for almost nothing. Here's how to get the most out of it before that window closes.
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Fable works differently from every model before it. Older models needed you to spell out every step. Fable follows instructions so well that a few clear lines beat a wall of rules. Here are the six things that matter.
This is the main event. Fable is built to take one big goal and run the whole thing end to end, on its own, for minutes or even hours. You hand over the goal, not the steps.
/goal and /loop. These two commands are how you set it loose:
/goal runs until the job is done, then stops. Like "research until you can answer these 5 questions" or "build this app."/loop does the same, but repeats on a schedule. Like a market brief every morning, or an inbox scan every 30 minutes.Fable is the smartest model, but it uses about twice the tokens of Opus 4.8, so running everything through it gets expensive fast.
So don't. Use Fable for the part it's best at: the thinking. Let it plan the whole job out first. Then let Fable run that plan and hand the repetitive work to cheaper models like Sonnet or Haiku, while it supervises. Fable's brain on the hard part, a cheap model doing the legwork. On a big project that saves you a lot. On small stuff, don't bother, just run Fable.
Fable has an effort setting that controls how hard it thinks. Two you need to know: