Unverified50% confidenceFactExact time
This ultrathink behavior covers four models: Opus 5.5, Sonnet 5.5, Haiku 5.5, and Fable 5.1.
1
Sources
50%
Confidence
Medium-term (~90 days)
Relevance
10/27/2026
First Seen
Valid until: 1/25/2027
Sources
Related Entities
Related Claims
UnverifiedVerified security professionals can use the Claude Mythos 5.1, Opus 5.5 and Sonnet 5.5 models.74% similarVerifiedHaiku 5.5 can work as a sub-agent alongside Claude Opus 5.5 and Sonnet 5.5 to complete programming tasks.73% similarUnverifiedFable 5.1 is the overall best frontend design model in the author's evaluation, while Sonnet 5.5's design capability is weaker than both Opus and Fable.72% similarUnverifiedThe three tiers of the Claude 5.5 family (Opus, Sonnet, and Haiku 5.5) all come with a 1 million token context window.65% similarUnverifiedAnthropic officially states that Opus 5.5 achieves Fable 5.1-level coding performance on most tasks.65% similar
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