Anthropic has reportedly revoked OpenAI's access to its Claude API after discovering that OpenAI engineers were using Claude's coding tools. This occurred prior to the anticipated launch of GPT-5. Despite the access revocation, Anthropic stated it will continue providing API access to OpenAI specifically for benchmarking and safety evaluations. The initial access appears to have been terminated due to concerns over competitive advantage or potential misuse of Claude's capabilities in the development of GPT-5.