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Claude isn't one thing anymore.
Open the model menu and you'll see a few names. Sonnet. Opus. Haiku. And in the headlines lately, Fable.
Most people pick one at random and never think about it again.
That's usually fine. But knowing the difference takes thirty seconds and saves you time, money, and frustration.
This is the plain-English guide.
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Okay, the lineup, in the order you'll actually use them.
Sonnet 5. Your default. Use this for almost everything.
Fast, sharp, and it now finishes multi-step jobs on its own. Writing, planning, inbox, research, learning. If you're not sure, it's Sonnet. It's the one you're already on if you're on Free or Pro.
Haiku. The quick one.
Lighter and faster, built for simple, high-volume tasks. Quick rewrites, short answers, anything where speed beats depth. You'll rarely pick it by hand, but it's there.
Opus 4.8. The heavy thinker.
Anthropic's top reasoning model. Reach for it when a problem is genuinely hard and Sonnet's answer feels thin. Deep analysis, tricky strategy, complex writing. Slower and pricier, so save it for the hard stuff.
Fable 5. The frontier.
The most powerful model, back as of this month. Built for heavy, days-long, autonomous work, mostly run by developers and teams through the API. Powerful, premium, and overkill for everyday chat.
So the rule of thumb.
Start on Sonnet 5. Move up to Opus when a hard problem needs more muscle. Ignore Fable unless you're building something big.
Simple as that.
One thing most people get wrong, though.
They blame the model when the answer is weak. Usually the model was fine. The brief was the problem.
A clear, well-fed prompt on Sonnet 5 beats a lazy prompt on the most expensive model every time.
So before you go reaching for something bigger, try giving Claude more context and a sharper instruction. Nine times out of ten, that's the fix.
Not sure which one you're on? Paste this into Claude:
Which Claude model am I talking to right now, and what is it best at? In one short paragraph, tell me whether it's the right choice for [describe the kind of work you do most], or whether I should switch.Which model, and how to drive each one well, is part of the foundation I teach in Claude Mastery.
The full system for getting a team's worth of work out of Claude. Step by step, no tech background needed.
Quick one.
Which model are you on right now? Reply and I'll tell you if it's the right call for what you're doing.
Talk soon,
Zephyr
