In particular, that marathon refactoring claim reportedly comes from Rakuten, a Japanese tech services conglomerate that "validated [Claude's] capabilities with a demanding open-source refactor running independently for 7 hours with sustained performance," Anthropic said in a news release.

Anthropic's Claude 4 models show particular strength in coding and reasoning tasks, but lag behind in multimodality and context window size compared to Google and OpenAI offerings.

Bowman later edited his tweet and the following one in a thread to read as follows, but it still didn't convince the naysayers.

Learn how Claude 4’s advanced AI features make it a game-changer in writing, data analysis, and human-AI collaboration. Anthropic's Claude 4

Anthropic's Claude Opus 4 outperforms OpenAI's GPT-4.1 with unprecedented seven-hour autonomous coding sessions and record-breaking 72.5% SWE-bench score, transforming AI from quick-response tool to day-long collaborator.

Anthropic's newest editon of its flagship AI product will address significant limitations in current large language models.

Anthropic just unveiled its Claude Opus 4 and Claude Sonnet 4 models. Just like all other AI companies, Anthropic is working on AI agents that can work for you. This goes far beyond simply using a chatbot.