Anthropic introduces Claude Fable 5.1, replacing Fable 5

Anthropic's model overview now lists Claude Fable 5.1 as the top-tier model for demanding reasoning and long-horizon agentic work, replacing Claude Fable 5. The new model has a knowledge cutoff of Jun 2026 (vs Jan 2026 for Fable 5). API ID is claude-fable-5-1. This is a new model launch, not a break

Sep 1, 2026 (UTC)Views:1

Anthropic Overview

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Anthropic Models Docs

Models overview Claude Fable 5.1

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