The launch came as the San Francisco-based startup held its first developers conference.

"Claude Opus 4 is our most powerful model yet, and the best coding model in the world," Anthropic co-founder and chief executive Dario Amodei said as he opened the event.

Opus 4 and Sonnet 4 were described as "hybrid" models capable of quick responses as well as more thoughtful results that take a little time to handle well.

Anthropic's gathering came on the heels of annual developers conferences from Google and Microsoft at which the tech giants showcased their latest AI innovations.

Since OpenAI's ChatGPT burst onto the scene in late 2022, various generative GenAI models have been vying for supremacy.

GenAI tools answer questions or tend to tasks based on simple, conversational prompts.

The current focus in Silicon Valley is on AI "agents" tailored to independently handle computer or online tasks.

Anthropic was early to that trend, adding a "computer use" capability to its model late last year.

"Agents can actually turn human imagination into tangible reality at unprecedented scale," said Anthropic chief product officer Mike Krieger, a co-founder of Instagram.

AI agents can boost what engineers at small startups can accomplish when it comes to coding, helping them build products faster, Krieger told the gathering.

"I think back to Instagram's early days," Krieger said. "Our famously small team had to make a bunch of very painful either/or decisions."

GenAI can also provide startup founders with business strategy insights on par with those of veteran chief financial officers, according to Krieger.

Anthropic, founded by former OpenAI engineers, launched Claude in March 2023.

The startup stresses responsible development of AI, moving more cautiously than competitors as it innovates.