Anthropic releases Claude Opus 5.5 model

Claude Opus 5.5, the first model in the Claude 5.5 family, performs at the level of Fable 5.1 on most tasks and costs 40% less to run than Opus 5.

Claude

@claudeaiArchived 2026.09.23Originally posted 2026.09.23

Claude @claudeaiOriginally posted 2026.09.23

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Introducing Claude Opus 5.5, the first model in our new Claude 5.5 family. It performs at the level of Claude Fable 5.1 for most tasks, and costs 40% less to run than Opus 5. https://t.co/Q9C2VKQ79f

x.com/claudeai/status/2102435511222890900Archived 2026.09.23 10:43

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