OpenAI slashes prices in half with GPT-6 Sol and Luna – just 90 minutes after Anthropic dropped Claude Opus 5.5
OpenAI today launched GPT-6 Sol and GPT-6 Luna, two faster, cheaper models in its new GPT-6 family, and cut API prices in half compared with the GPT-5.6 versions they replace. The timing wasn’t subtle: the announcement landed roughly 90 minutes after Anthropic released Claude Opus 5.5, according to TechCrunch.
Meet Sol and Luna
Both models build on GPT-6 Astra, the flagship OpenAI released earlier this month, bringing “much of its strengths into faster and more affordable models,” the company says.
- GPT-6 Sol is the all-rounder, aimed at complex work like interactive and agentic coding.
- GPT-6 Luna is the lightweight option, for “high-volume tasks with a clear goal, like summarizing documents, extracting information, or answering quick questions.” It’s the cheapest model in the GPT-6 family.
GPT-6 Sol makes about half as many mistakes as its predecessor, reaching Astra-level reliability at much lower cost.
OpenAI
The price cut
The headline number is price. Per million tokens, the new API rates are:
- GPT-6 Sol: $2 input, $10 output
- GPT-6 Luna: $0.10 input, $0.50 output
That’s 50% below the promotional pricing of the GPT-5.6 models, a cut OpenAI attributes to improvements in caching and inference. “We want the OpenAI API to feature the best model at every price point and modality,” CEO Sam Altman said, according to Pulse 2.0.
The benchmarks, and a catch
At its highest reasoning setting, OpenAI says Sol scores 33.2% on AutomationBench, a test of business workflows, at about $0.27 per task. It also reports 56.4% on Agents’ Last Exam, 60.5% on the OSWorld 2.0 computer-use benchmark, and 68.8% on the DeepSWE v1.1 software engineering test, where Luna isn’t far behind at 66.6%.
OpenAI claims the new models beat Anthropic’s Fable and Opus models. But the head-to-head numbers it published compare Sol with Claude Opus 5, which scored 26.9% on AutomationBench at 11 times the cost per task. That’s the model Anthropic replaced 90 minutes before OpenAI’s announcement, so how Sol stacks up against the brand-new Opus 5.5 is still an open question.
Anthropic’s move
Claude Opus 5.5 is the first model in Anthropic’s new 5.5 family. The company says it performs at the level of Claude Fable 5.1 on most work, costs 40% less to run than Opus 5, and generates output more than 30% faster. Its API price drops to $4 per million input tokens and $20 per million output tokens.
Anthropic is also removing the five-hour usage caps for Pro, Max, Team and seat-based Enterprise subscribers, and says Sonnet 5.5 and Haiku 5.5 will follow within weeks, TechCrunch reports.
How to get them
GPT-6 Sol and Luna are available now in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu subscribers, and rolling out to the ChatGPT app and website throughout the day. Free and Go users can use Luna in the ChatGPT desktop app. Developers can call them in the API as gpt-6-sol and gpt-6-luna, and both are already available in GitHub Copilot.
Sources: OpenAI, TechCrunch, Decrypt, Pulse 2.0, TechCrunch (Opus 5.5), GitHub