Corroborated event · 10 outlets
Anthropic unveiled Claude Opus 5.5, while OpenAI launched GPT-6 Sol and Luna, with both releases accompanied by significant price cuts across the industry.
AI brief
Anthropic released Claude Opus 5.5, and about an hour later OpenAI released GPT-6 Sol and GPT-6 Luna. The releases followed Grok 4.7 and MiMo v2.6 Flash/Pro a day earlier.
Written by AI from Simon Willison's Weblog's published text. Read the original for full details.
More coverage of this story (15)
Anthropic releases Claude Opus 5.5 and OpenAI launches GPT-6 Sol and Luna
Frontier AI keeps racing despite calls to slow down
The Register AI + ML · 23 Sept 2026, 00:02
Anthropic releases Claude Opus 5.5 and OpenAI counters with two cheaper GPT-6 models
SiliconANGLE AI · 22 Sept 2026, 22:58
New Anthropic, OpenAI models make same promise: A little more for a lot less money
Ars Technica AI · 22 Sept 2026, 21:25
Better prompt caching for GPT-6
OpenAI News · 22 Sept 2026, 21:00
OpenAI's GPT-6 Sol and Luna cut prices in half but barely move the needle on performance
The Decoder · 22 Sept 2026, 20:06
llm 0.36
Simon Willison's Weblog · 22 Sept 2026, 18:48
Bring more intelligence to everyday work with GPT-6 Sol and GPT-6 Luna on Amazon Bedrock
AWS Machine Learning Blog · 22 Sept 2026, 18:10
OpenAI launches GPT-6 Sol and Luna, boasting lower cost and fewer mistakes
TechCrunch AI · 22 Sept 2026, 18:00
Introducing GPT-6 Sol and Luna
OpenAI News · 22 Sept 2026, 18:00
Claude Opus 5.5 is now available on AWS
AWS Machine Learning Blog · 22 Sept 2026, 17:28
llm-anthropic 0.29
Simon Willison's Weblog · 22 Sept 2026, 17:14
Claude Opus 5.5 matches Fable 5.1 performance at lower cost and promises less "Claudish" writing
The Decoder · 22 Sept 2026, 16:31
Anthropic launches Claude Opus 5.5 with stricter safeguards for cybersecurity
The Verge AI · 22 Sept 2026, 16:30
Anthropic releases Opus 5.5 with lower prices and Fable-level performance
TechCrunch AI · 22 Sept 2026, 16:30
Anthropic and OpenAI announce more powerful (and cheaper) AI models
Engadget AI · 22 Sept 2026, 07:30
Primary source
Interpretation or community commentary rather than straight reporting.
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