The gloves have been taken off in the AI ​​race, and Elon Musk is not holding back. The tech billionaire has publicly attacked Anthropic after the AI ​​startup blocked access to its cloud AI models for Musk’s AI firm, XAI. The move came after xAI employees were reported to be using the cloud’s AI models.

Elon Musk calls Anthropic’s decision to block XAI bad for karma

On Twitter, Elon Musk responded to a post that shared a screenshot of his statement from November 2025. At the time, Musk said that Grok 4.2 could outperform Anthropic’s Opus 4.5 model. In his response, the tech billionaire admitted that it may be difficult to outperform Anthropic when it comes to coding models, however, he stressed that the company’s decision to block xAI will not help them in Karma.

Elon Musk wrote, “Not exactly on programming, but it will excel in other areas. Anthropic did something special with coding. It was a helpful motivator that they cut us off from @xAI and that’s not good for their karma.”

Grok 4.2 is set to be released in early 2026. However, Musk has not yet given any concrete timeline.

Why did Anthropic block xAI’s access to its AI models?

Anthropic’s recent move to block XAI from accessing its cloud models through coding platform Cursor follows concerns within Anthropic that its technologies are being used to enhance a direct competitor’s systems.

xAI’s developers were informed of the decision this week in an internal email, which was first reported by tech journalist Kylie Robison. “Hi team, I believe many of you have already discovered that Anthropic models are not responding to cursors,” XAI co-founder Tony Wu wrote in an email.

While Wu acknowledged that this would impact xAI’s productivity, the company will work harder on its models. He added, “We will hit productivity, but it really forces us to develop our own coding products and models.”

However Anthropic’s new policy targets all major competitors, not just xAI. This has left xAI engineers unable to use the cloud to support their software development process.

Anthropic’s terms of service explicitly prohibit customers from using its AI to develop competing products or train rival systems, even through indirect means such as third-party platforms. The ban was reportedly triggered by xAI’s usage patterns via cursors, which are commonly used by developers to access various AI models for code generation and improvement.

This is not the first time Anthropic has implemented such measures. The company previously withdrew API access from OpenAI and limited other coding services when it felt its technology could give competitors an advantage. Additionally, Anthropic has recently tightened controls to prevent third-party tools from rigging pricing through consumer plans and has banned accounts that abuse the system.