Anthropic Launches Claude Fable 5.1: Major Long-Horizon Agent Boost, 4x Cheaper Cache
Wes Roth · youtube · 2026-09-02
Anthropic released Claude Fable 5.1 and Mythos 5.1, featuring significant improvements in long-horizon agentic work. Prompt cache reads are now 4x cheaper, and the model burns significantly fewer tokens for the same tasks. The release coincides with OpenAI's announcement of Astra. Demonstrations include building a fully-voiced Tarkov-style extraction game and a replica of Stanford's "LLM Village" in roughly 10–15 minutes.
Related event: Anthropic Launches Claude Fable 5.1 with 75% Cache Price Cut(72 posts)→
More from coding & agent
- Optimizing Grok Bot usage by combining Herdr with CLI tools — mazzaTalk · 2026-09-02
- Claude Fable 5.1 preserves prompt cache when adjusting thinking effort — brandon_galang · 2026-09-02
- Steve Yegge: All models will eventually build systems they can't maintain — Steve_Yegge · 2026-09-02
- A working pattern: agent finds customers, negotiates, delivers, and invoices via Stripe — jeff_weinstein · 2026-09-02
- Ramp builds a semantic layer linking AI spend to ROI by decoding agent traces — graceisford · 2026-09-02
- One voice command makes AI pull all project artifacts and render an iteration timelapse — apostraphi · 2026-09-02