Anthropic has revoked OpenAI’s access to its Claude family of models, according to a Wired report. OpenAI was connecting its own internal tools to Claude to allow the company to compare Claude’s performance to its own models in categories like coding, writing, and safety, according to the report.
“Claude Code has become the go-to choice for coders everywhere, and so it was no surprise to learn OpenAI’s own technical staff were also using our coding tools ahead of the launch of GPT-5,” Anthropic spokesperson Christopher Nulty said in a statement to WIRED. “Unfortunately, this is a direct violation of our terms of service.” However, Anthropic also said it would give OpenAI access for “for the purposes of benchmarking and safety evaluations.”
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Meanwhile, an OpenAI spokesperson described its usage as “industry standard” and added, “While we respect Anthropic’s decision to cut off our API access, it’s disappointing considering our API remains available to them.”
Anthropic’s Terms of Service restricts customers from using the service to “build a competing product or service, including to train competing AI models” or “reverse engineer or duplicate” the services. This comes ahead of OpenAI’s launch of its latest model GPT-5.
Previously, Anthropic had cut off AI coding startup Windsurf’s access to Claude, when there were talks of a possible acquisition of the startup by OpenAI. “We really are just trying to enable our customers who are going to sustainably be working with us in the future,” Anthropic Co-Founder and Chief Science Officer Jared Kaplan said while addressing this issue. “I think it would be odd for us to be selling Claude to OpenAI.” The acquisition ended up not coming through, and Windsurf was acquired by Cognition instead. Cognition said in a press release that Windsurf will now have full access to Claude AI models once again.
The practice of top tech companies removing API access from their competitors has been a long-standing one. Facebook did the same to Twitter-owned Vine (which led to allegations of anticompetitive behavior) and last month Salesforce restricted competitors from accessing certain data through the Slack API.
Meanwhile, OpenAI is all set to release its GPT-5 model. OpenAI CEO Sam Altman had recently mentioned in an episode of This Past Weekend with Theo Von podcast that he felt unsettled while testing GPT-5. “It feels very fast,” he said, adding that he felt “very nervous” during some of the sessions. He even said he “sort of felt like it was the Manhattan project.” While GPT-5 is expected to be significantly faster and smarter than GPT-4, Altman did not go into the technical specifics while discussing his concerns about GPT-5.