You don't need to follow every launch. You need to know which brain fits which job. Bookmark this page and stop overthinking it.
Start with whatever you already have open. Upgrade only when the task feels too big for it. That's the whole system.
Emails, summaries, to-do lists, brainstorming, rewriting something to sound better, quick questions.
Use Claude (Sonnet 5) or ChatGPT, whichever you already use. Both handle this easily. Sonnet 5 is now what Claude gives every account for free, so if you use Claude, you're already on it.
Long documents, comparing options with lots of moving parts, multi-step projects, anything where you'd say "this needs real focus."
Use Claude (Fable 5) if you're on a paid plan. It's Anthropic's most powerful model. Think of it as the pro camera: you don't need it for lunch photos, you want it for the wedding.
Used Fable 5 on a small task by mistake? No harm done. The answer is fine, it just took longer and used up more of your plan's usage limit. Switch back to Sonnet for everyday tasks and save the heavy model for heavy work.
Creating images, talking out loud while cooking or driving, describing a photo.
ChatGPT is strong here. This is a great example of "right tool for today," not "best tool overall."
Do nothing. Read one headline if you're curious. Your current setup did not get worse. If the new model is a real upgrade for your daily tasks, it will usually show up in your app on its own, like Sonnet 5 just did.
Whatever model you use, the same rule applies: don't paste in anything you wouldn't want a stranger to read. No passwords, no health records, no confidential work documents. When in doubt, leave it out.