Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and a new price war
GPT-6 Luna and Sol arrived at half the GPT-5.6 price, while Claude Opus 5.5 cut prices but stumbled at max reasoning.
Willison says GPT-6 Luna is now $0.10/M input and $0.50/M output, making it one of OpenAI’s cheapest releases. GPT-6 Sol also halves the GPT-5.6 Sol price, putting pressure on Grok 4.7 and Anthropic’s mid-tier pricing. Claude Opus 5.5 drops to $4/M input and $20/M output, with cheaper cache reads, but failed his SVG pelican test twice at “max” thinking by exhausting its output limit while reasoning. He is now using GPT-6 Sol and Claude Opus 5.5 as defaults in his coding tools, and moved his Datasette Agent demo to GPT-6 Luna. Simon Willison's note
Willison says GPT-6 Luna is now $0.10/M input and $0.50/M output, making it one of OpenAI’s cheapest releases. GPT-6 Sol also halves the GPT-5.6 Sol price, putting pressure on Grok 4.7 and Anthropic’s mid-tier pricing. Claude Opus 5.5 drops to $4/M input and $20/M output, with cheaper cache reads, but failed his SVG pelican test twice at “max” thinking by exhausting its output limit while reasoning. He is now using GPT-6 Sol and Claude Opus 5.5 as defaults in his coding tools, and moved his Datasette Agent demo to GPT-6 Luna. Simon Willison's note
score 9