Anthropic (ANTH.PVT) debuted its Claude Opus 5 AI model on Thursday, the fourth in its Claude 5 family of models, which also includes its powerful Mythos 5 and Fable 5.
Fable 5 is Anthropic's most capable publicly available model, meant for "days-long autonomous projects," the company said. Mythos 5 is Anthropic's current cutting-edge model, but the AI lab has limited availability to a select group of companies and organizations due to its impressive hacking capabilities.
The company is framing Opus 5 as the go-to AI model for most tasks, including knowledge work and automation. According to Anthropic, Opus 5 approaches Fable 5's competencies at half the cost.
Unlike Fable 5, Opus 5 doesn't retain user data for 30 days. Anthropic says it retains user inputs and outputs for Fable 5 as part of its safety efforts and to prevent future misuse.
Opus 5 comes after OpenAI (OPAI.PVT) released its GPT-5.6 family of models earlier this month. Google is also preparing to release its Gemini 3.5 Pro model, but according to Bloomberg, it's been delayed.
Google pushed back against the report.
The Trump administration initially forced Anthropic to pull its Mythos 5 and Fable 5 models from the market over cybersecurity concerns, only to allow the company to reinstate them later. OpenAI voluntarily submitted its GPT-5.6 Sol to the administration for evaluation purposes before releasing it more widely.
The companies are in a constant race to release increasingly powerful models to stay ahead of each other, as well as China-based AI companies.
Last week, China's Moonshot AI debuted its open-weight Kimi K3 model, which the lab said was nearly as powerful as both Fable 5 and GPT-5.6 Sol.
Staying ahead in the AI race is also paramount as Anthropic and OpenAI prepare for their initial public offerings. Anthropic filed confidential paperwork to go public in June, followed shortly by OpenAI, and Anthropic appears to be on track to hit the market later this year.
OpenAI, however, may delay its IPO until 2027. It also has to contend with Apple's (AAPL) trade secrets lawsuit, which alleges that the company stole proprietary information from Apple, further complicating its plans to go public.
Email Daniel Howley at dhowley@yahoofinance.com. Follow him on X at @DanielHowley.
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