Dan Shipper@danshipperSep 1

BREAKING: Anthropic just dropped Fable 5.1—and CLAUDE IS SO BACK. We’ve spent the last week testing it at @every across coding, writing, and knowledge work. Our verdict: It's finally Fable for everyone. It’s the strongest coding model we’ve used, but now it's fast, token-efficient, and CRUCIALLY actually speaks like a normal person. Here’s our vibe check: - A monster at coding. @kieranklaassen rebuilt a working version of Proof, our document editor, from one prompt. It added useful details he hadn’t requested, and it handles enormous coding jobs that run for days at a time. It built a computer use Mac app for me called Hands in one-shot that other models failed at. - A Claude our writers want to use again. It has clearer prose, fewer AI tells, and it takes an edit without arguing. It's a significant upgrade over Opus 5. And won @kplikethebird's heart back. - About half the tokens as Opus 5, and much faster. In our Slack-agent tests, it delivered comparable results to Opus 5 using about half as many tokens, in about 60% of the time. - Knowledge work you can delegate. It can produce great knowledge work—like slide decks—end to end without making slop. And flew threw @hammermt's tests with flying colors. - It now supports zero-data-retention agreements. Now businesses can actually use it! A big barrier to Fable adoption is gone. Net Result: It's obviously an Opus 5 killer. If that was your daily driver you should switch today. If you're using GPT-5.6 in ChatGPT for Work, it's spinning the wheels on for big delegated tasks. I still use ChatGPT for Work more day to day, but I use way more tokens in Fable 5.1. I send it off at the beginning of the day to do big programming projects, like end to end MVP builds, and check in every once in a while. State of Play: The big knock on Anthropic was they built a supergenius in a datacenter that was almost unusable. It was too slow, argued back, and talked in technical gibberish. They've managed to solve those problems and more with Fable 5.1!