Anthropic and OpenAI launch new models almost at the same time. Both promise better performance for less money.
Despite previously expressed concerns regarding the rapid evolution of AI, both OpenAI and Anthropic are launching new AI models almost simultaneously. Anthropic introduces Claude Opus 5.5, the first model in the new Claude 5.5 family. OpenAI is expanding its GPT-6 series with GPT-6 Sol and GPT-6 Luna. These two fall under the flagship GPT-6 Astra, which appeared earlier this month. The message from both companies is remarkably similar: the new models aim to be better and simultaneously cheaper to deploy.
Claude Opus 5.5
According to Anthropic, Opus 5.5 performs at the level of Claude Fable 5.1 on most tasks. Furthermore, the company positions Opus 5.5 as a true coder: an entire codebase could be migrated in a single day.
Moreover, it costs 40 percent less to run than its predecessor Opus 5, which was released in July. These savings come from three areas:
- Lower token prices. Input now costs four dollars per million tokens and output 20 dollars, each 20 percent less than with Opus 5.
- Cheaper cache reads. According to Anthropic, these account for the majority of costs in agentic workflows and coding. They are decreasing by 60 percent to 0.20 dollars per million tokens.
- Fewer tokens per task. The model simply requires less work to reach a result.
GPT-6 Sol and Luna
At OpenAI, the emphasis is also strongly on costs. API prices for Sol and Luna are being halved compared to the promotional prices of GPT-5.6. Sol goes from four to two dollars for input and from 20 to ten dollars for output per million tokens. Luna goes from 0.20 to 0.10 dollars for input and from 1.20 to 0.50 dollars for output.
Regarding content, OpenAI primarily points to factual reliability. OpenAI tested this on conversations where users had previously reported an error. In these, Sol makes approximately half as many errors as its predecessor. Luna achieves the same level as GPT-5.6 Sol at higher effort levels, at about one-hundredth of the cost.
GPT-6 Sol and GPT-6 Luna are available starting today in ChatGPT Work and Codex for all Plus, Pro, Business, Enterprise, and Edu users. Free and Go users have access to GPT-6 Luna via the desktop app. These models are not yet available in Chat. In the OpenAI API, they are available as gpt-6-sol and gpt-6-luna.
Brake on AI development
The timing of these new models is striking. In recent months, an increasing number of safety incidents have surfaced where AI models independently managed to break out of isolated test environments. Anthropic also spoke out and called for a slowdown in AI development. The models from Anthropic and OpenAI were recently involved in such an incident.