Anthropic ships Claude Opus 5.5: Fable 5.1-level work, 40% cheaper
2026·09·27 · 1 min read
Photo: Mizuno K · Pexels
Released September 22, 2026. Anthropic says it matches Claude Fable 5.1 on most work while costing 40% less to run than Opus 5, with cache reads down 60%.
Anthropic released Claude Opus 5.5 on September 22, 2026, the first model in the Claude 5.5 family.
The claims, from the announcement:
- Performs at the level of Claude Fable 5.1 on most work, and costs 40% less to run than Opus 5 — a combination of a lower unit price and fewer tokens spent per task.
- $4 per million input tokens and $20 per million output, 20% below Opus 5.
- Cache reads at $0.20 per million, 60% cheaper. Anthropic notes cache reads are the majority of the cost in agentic and coding work, so this is the number that shows up on a real invoice.
- Generates output more than 30% faster than Opus 5.
- A fast mode is available in Claude Code and the platform at up to 2.5x speed, priced at $8 / $40 per million tokens.
On the release process, the announcement points to pre-release evaluation by outside organizations including METR and Frontier Design, and says the model ships with preserved thinking, the anti-distillation safeguard introduced with Fable 5.1, which blocks API users from editing prior context to extract the model's reasoning.
Source: Anthropic, "Introducing Claude Opus 5.5" (September 22, 2026).