Is the AI Slowdown Over? OpenAI and Anthropic Just Launched New Models

Anthropic and OpenAI launched new artificial intelligence (AI) models less than two hours apart on Tuesday. Both releases landed only 10 days after their chief executives publicly pushed for an AI slowdown.

This time, however, instead of pushing past their most powerful models, both cut prices instead, and Elon Musk who had also backed the AI slowdown initiative, congratulated Anthropic.

Congrats!

— Elon Musk (@elonmusk) September 22, 2026

Anthropic Ships Opus 5.5 After Its AI Slowdown Call

Anthropic released Claude Opus 5.5 at 16:31 UTC. The company said the model matches its Claude Fable 5.1 on most tasks and costs 40% less to run than Opus 5.

Introducing Claude Opus 5.5, the first model in our new Claude 5.5 family.It performs at the level of Claude Fable 5.1 for most tasks, and costs 40% less to run than Opus 5. pic.twitter.com/Q9C2VKQ79f

— Claude (@claudeai) September 22, 2026

That 40% figure comes from Anthropic’s own tests on typical workloads. List prices fell 20%, to $4 per million input tokens and $20 per million output tokens. Tokens are the chunks of text a model reads and writes, and developers pay per token.

Opus 5.5 is Anthropic’s first model since CEO Dario Amodei published an essay on September 12 urging labs to slow capability gains. OpenAI CEO Sam Altman agreed, and Musk wrote “Dario is right,” as BeInCrypto reported.

However, Amodei’s essay left room for new launches.

“…pacing does not mean halting model training or technical progress, but ensuring companies take adequate time to align and safeguard their models,” wrote Amodei.

Anthropic said outside testers METR and Frontier Design reviewed Opus 5.5 before release.

OpenAI Answers With Cheaper GPT-6 Sol and Luna

OpenAI introduced GPT-6 Sol and GPT-6 Luna at 18:12 UTC. Both are faster, lower-cost models built on GPT-6 Astra, which remains its flagship.

Please welcome GPT-6 Sol and GPT-6 Luna to the GPT-6 universe.GPT-6 Sol and Luna build on the advances behind GPT-6 Astra, bringing much of its strengths into faster and more affordable models to support work at scale.We’ve also made caching and inference more efficient, and… pic.twitter.com/5LiVE4rbFt

— OpenAI (@OpenAI) September 22, 2026

The company halved prices for developers. Sol now costs $2 per million input tokens, while Luna costs $0.10. Meanwhile, that 50% cut is measured against GPT-5.6 promotional pricing, not standard rates.

Paid ChatGPT users get both models today. Free users can try Luna in the desktop app.

Skeptics had questioned the slowdown pledge from the start. Investor Michael Burry called it self-serving IPO hype. Morgan Stanley, an Anthropic IPO underwriter, said the push changes nothing for spending.

Neither lab has said when it will ship a model above its current flagship.