Quoting Drew Breunig

Drew Breunig, in a blog post titled 'Fable & The End of the Free Lunch,' argues that Anthropic's Claude model 'Fable' marks the end of the era where new AI models automatically improve coding workflows at the same price. Breunig notes that while Fable is 'incredible,' its high cost and the adequacy of alternatives like Opus, 5.6, K3, and GLM for most coding tasks have forced developers to strategically allocate work across models. This shift signals a departure from the assumption that each new model would render previous optimization efforts obsolete.

Prior to Fable, it felt silly to waste toomuch time improving your coding harness or context strategies. A new model would arrive at the same price or cheaper and paper over most of your problems.But then Fable landed. It was and still is incredible. But the cost was so high and Opus wasgood enough as was 5.6, K3, and even GLM formostof the code we needed. So we started to think about what work went where. — Drew Breunig https://www.dbreunig.com/2026/08/23/fable-the-end-of-moore-s-law.html , Fable & The End of the Free Lunch Tags: drew-breunig https://simonwillison.net/tags/drew-breunig , anthropic https://simonwillison.net/tags/anthropic , claude https://simonwillison.net/tags/claude , llm-pricing https://simonwillison.net/tags/llm-pricing , ai https://simonwillison.net/tags/ai , llms https://simonwillison.net/tags/llms , generative-ai https://simonwillison.net/tags/generative-ai , claude-mythos-fable https://simonwillison.net/tags/claude-mythos-fable