Claude Opus 5.5

The Short Version Sol and Luna are not new names: they arrived this summer as part of GPT-5.6. On 22 September 2026 OpenAI moved both to GPT-6 and halved the price, roughly 90 minutes after Anthropic shipped Claude Opus 5.5. Sol: $2 in / $10 out per million tokens. Opus 5.5 is $4 / $20, so Sol is exactly half. Luna: $0.10 / $0.50, 40x cheaper than Opus 5.5. Free and Go users get it in the ChatGPT desktop app. Every OpenAI chart compares against Opus 5, not Opus 5.5. On the one benchmark both vendors report, Opus 5.5 leads: 40.0% vs 33.2% on AutomationBench. Pick Opus 5.5 for quality, Sol for volume, Luna for simple high-volume jobs. GPT-6 Sol vs GPT-5.6 Sol: What Changed? The Sol, Terra and Luna tiers first shipped this summer with GPT-5.6 . Earlier this month GPT-6 Astra took the top slot, while Sol and Luna stayed on GPT-5.6. This release moves those two onto the GPT-6 generation: Sol for coding and agentic work, Luna for high-volume jobs with a clear goal, such as summarising documents, extracting fields or answering quick questions. ...

Summary: Claude Opus 5.5 in 30 Seconds Released 22 September 2026, available the same day on every platform Anthropic ships to. $4 in / $20 out per million tokens, against $5 / $25 on Opus 5. Cache reads drop from $0.50 to $0.20. Anthropic measures a 40% lower total cost on typical workloads and 30%+ faster output generation. Model ID is claude-opus-5-5. Four breaking API changes land with it. Sonnet 5.5 and Haiku 5.5 follow in the coming weeks. What Opus 5.5 Costs The headline price is 20% under Opus 5, but the number that moves most bills is the cache read rate. On agentic and coding work, cache reads are where the majority of spend lands, and they got 60% cheaper. ...