The conversation in the AI industry has largely been focused on slowing down AI development or “pacing the frontier,” but that apparently won’t stop Anthropic and OpenAI from releasing new models. Both companies are iterating on their previous releases, Fable 5.1 and GPT-6 Astra, with new models that offer similar levels of performance but at lower costs.

In the case of Claude, Anthropic says its new Opus 5.5 model is better at handling complex work, “finding and fixing inefficiencies in software” and financial analysis and business work — all pitches laser-targeted at Anthropic’s enterprise customers. Anthropic’s benchmarks claim Opus 5.5 also scored better at agentic coding than GPT-6 Astra on both Terminal-Bench 4.0 and FrontierCode v1.1 (Main), which could make it more appealing for developers.

Improvements extend outside of the tasks the model can handle and to how it works: Anthropic claims Opus 5.5 produces writing that’s easier to understand, and that it “attempted to circumvent boundaries around 85 percent less often” than past models, suggesting it’ll disobey directions less often. Equally important, the company claims it costs less per token to use ($4 for input tokens and $20 for output tokens, compared to the $5 input and $25 output of Opus 5).

OpenAI’s new GPT-6 Sol and GPT-6 Luna models are similarly focused on efficiency. The new models were trained using similar methods to GPT-6 Astra and offer improvements across professional work, coding and computer use, but for up to 50 percent cheaper than the promotional pricing of their GPT-5.6 counterparts. Specifically, GPT-6 Sol input tokens cost $2, while output tokens cost $10. For Luna, input tokens cost $0.10, while output tokens cost $0.50.

In terms of improvements, both new GPT-6 models are better at getting facts right, with Sol making about half as many mistakes as its predecessor, according to OpenAI. In coding, the company says GPT-6 Sol is able to match the performance of Fable 5.1 at a lower cost, too. The new models also communicate more clearly, and thanks to improvements to prompt caching, OpenAI says they can reuse more context and respond faster.

OpenAI says the GPT-6 models are more aligned than before based on the company’s homegrown tests. For example, they lie less about the results of their coding work and deny even more attempts to bypass safeguards when they receive an unsafe command. Like Anthropic, OpenAI has also proposed its own criteria for third-party evaluators to use when judging the progress and safety of AI development. Whether these proposals will lead to some kind of industry-wide standard remains to be seen though.

Anthropic’s Opus 5.5 model is available to developers now through Claude, Amazon Web Services, Google Cloud and Microsoft Azure. OpenAI’s GPT-6 Sol and GPT-6 Luna are both available in ChatGPT Work and Codex for Plus, Pro, Business and Enterprise customers. Free users and Go subscribers will have access to only GPT-6 Luna in the company’s desktop app.