Claude Opus 5.5: Anthropic's model that performs like Fable and costs less

September 22, 2026 · JICA LABS

On September 22, 2026, Anthropic launched Claude Opus 5.5, the first model in its new 5.5 family. The pitch is unusual: more capability for less money.

The key points

A striking example

Among its results, Anthropic highlights a 680,000-line code migration completed in under a day. On public benchmarks it reports, for example, 66.4% on Terminal-Bench 4.0 and 57.8% on CursorBench 4.0.

Where it is available

From launch day it is available in the Claude apps (Pro, Max, Team and seat-based Enterprise plans), in Anthropic's API as claude-opus-5-5, and on Amazon Web Services, Google Cloud and Microsoft Azure. Anthropic said Sonnet 5.5 and Haiku 5.5 will follow in the coming weeks with similar improvements.

Why it matters

The industry pattern had been that each more capable model was also more expensive. A model matching a larger one at a lower cost makes this level of AI practical for tasks where it did not pay off before. That same day, OpenAI answered with cheaper models of its own: see GPT-6 Sol and Luna. For a side-by-side look at what each costs, see our Claude vs GPT-6 vs Gemini pricing comparison.

Fun fact: these JICA LABS pages were built with help from Claude.

Sources

More notes