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Claude Opus 5.5 matches Fable 5.1 performance at lower cost and promises less "Claudish" writing

Technology · en

Claude Opus 5.5 matches Fable 5.1 performance at lower cost and promises less "Claudish" writing

The Decoder · Sep 22, 2026, 5:11 PM UTC

Anthropic is launching Claude Opus 5.5, the first model in a new generation. The company says it matches Claude Fable 5.1 on most tasks while costing about 40 percent less to run than Opus 5. Anthropic's benchmarks also put it ahead of OpenAI's GPT-6 Astra on most tasks, despite being significantly cheaper. Sonnet 5.5 and Haiku 5.…