Anthropic Revokes OpenAI's API Access to Claude Models Over Alleged Terms of Service Violations

Aug 1, 2025

Anthropic revokes OpenAI's API access to its Claude models, alleging OpenAI violated its terms of service by using Claude's coding tools to develop the upcoming GPT-5. OpenAI defends its actions as "industry standard" benchmarking and calls the move disappointing. The conflict, which follows Anthropic's similar block of a rumored OpenAI acquisition target, highlights escalating competitive tensions and the use of API access as a strategic weapon in the AI industry.

Anthropic revokes OpenAI API access

▪Anthropic stated it will continue to ensure OpenAI has API access for standard benchmarking and safety evaluations, without clarifying how this works with the current restriction.
▪Anthropic has revoked OpenAI's API access to its Claude family of AI models.

Terms of service violation dispute

▪OpenAI's CCO Hannah Wong defended the company's actions as an "industry standard" practice for benchmarking progress and improving safety.
▪OpenAI staff reportedly used special developer APIs to integrate "Claude Code" into internal tools for benchmarking, rather than using the public chat interface.
▪Hannah Wong of OpenAI also called Anthropic's decision "disappointing," noting that OpenAI's API remains available to Anthropic.
▪Anthropic alleges OpenAI violated its terms of service by using Claude's coding tools to support the development of its upcoming GPT-5 model.
▪Anthropic's commercial terms prohibit customers from using its services to "build a competing product or service" or to train rival AI models.

OpenAI GPT-5 development pressures

▪The GPT-5 launch is seen as a critical moment for OpenAI to reassert its leadership after a period of internal turmoil and strategic blunders.
▪The dispute occurs as OpenAI is reportedly preparing to launch its next-generation model, GPT-5, which is rumored to have superior coding capabilities.

Windsurf acquisition sabotage precedent

▪Anthropic's Chief Science Officer, Jared Kaplan, commented on the Windsurf situation, stating, "I think it would be odd for us to be selling Claude to OpenAI."
▪Anthropic previously revoked API access for Windsurf, an AI coding startup, amid rumors that OpenAI was planning to acquire the company.

AI industry competitive tactics

▪Restricting API access is a known competitive tactic in the tech industry, with historical examples including Facebook blocking Vine and Salesforce limiting Slack data access.
▪The day before blocking OpenAI, Anthropic announced new rate limits for its Claude Code service, citing "explosive usage" and terms of service violations by some users.