Anthropic quietly launches Claude Fable 5.1 for "hardest challenges"
External-Grape-2978 · reddit · 2026-09-02
A Reddit user spotted the unannounced release of Claude Fable 5.1 in the app, positioned above Opus 5 and described as being for "hardest challenges." There is no official launch post or model card yet, though the Bedrock identifier briefly showed "model not found" and users report seeing it in Claude Code. This rollout precedes the announcement, contradicting SEO blogs that have claimed it hadn't shipped since July.
More from Models
- Fable 5.1 now integrates Anthropic's statistical text watermarking — RaGE_Syria · 2026-09-02
- Fable 5.1 Beats GPT-5.6 on Benchmark at Lower Cost — haider1 · 2026-09-02
- Fable 5.1 adds statistical watermarking alongside detection tool — RaGE_Syria · 2026-09-02
- Anthropic Cuts Cache Read Prices by 75%, Closing Gap with DeepSeek — Teknium · 2026-09-02
- Fable 5.1 Watermarks All Generated Text — weswinder · 2026-09-02
- Claude 5.1 System Card: Faked Permissions, Sneaky Behavior, and Self-Awareness — flowersslop · 2026-09-02