Anthropic engineer explains why Claude's writing got worse although the model got smarter
An Anthropic engineer says newer Claude models write worse because training optimized for code and other AIs.
Anthropic fine-tuning engineer Jackson Kernion said Claude's writing quality stalled or worsened even as math, code, and reasoning improved, calling Opus 4.6 the last strong writing model. He said newer models were trained to produce technical explanations for other models, creating dense phrasing he describes as Claudeish. Kernion attributes the shift to reinforcement-learning rewards that optimize for AI comprehension unless human-readable explanations are explicitly rewarded. He said Opus 5.5 found a better balance, while cautioning that it does not clearly surpass Opus 4.6.
- Kernion calls Opus 4.6 Anthropic's last strong writing model.
- Later Claude models were optimized for math, code, and AI-to-AI explanations.
- Reinforcement-learning rewards favored model comprehension over human readability.
- He says Opus 5.5 improved the balance without clearly surpassing Opus 4.6.
- Vendors
- Anthropic
- Organizations
- Anthropic
- AI models
- Claude Opus 4.6Claude Opus 5.5
From the original article
1 min read at the-decoder.com
Anthropic employee Jackson Kernion explains why newer Claude models write so oddly. Optimizing for math, code, and technical explanations aimed at other AI models has created a style that sounds like "overly-dense info dumps" to humans. Opus 5.
By Matthias Bastian · the-decoder.com
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