Things are heating up between rival AI firms as they race to establish dominance in the fast-moving field.
Anthropic has reportedly cut off access to its models from xAI’s team, which was using them for coding. In turn, X’s product head Nikita Bier has said said X could end up banning Anthropic from the service.
“Hi team, I believe many of you have already discovered that Anthropic models are not responding on Cursor. According to Cursor this is a new policy Anthropic is enforcing for all its major competitors,” xAI’s xAI cofounder Tony Wu told staff on Slack as per a report by Kylie Robinson of Core Memory.
“This is a both bad and good news,” Wu added. “We will get a hit on productivity, but it rly pushes us to develop our own coding product / models. We’re at a time in which Al is now a critical technology for our own productivity. This coming year is rly going to be wildly exciting for all of us. The team is rapidly developing our own models / product. We will have something to share with everyone soon. In the meantime, you may still try all different kinds of models in grok build,” he said.
xAI had presumably been using Anthropic’s models to code using Cursor, and given how it is a rival, Anthropic appears to have cut access to these models. Elon Musk has previously said that Anthropic’s models were ‘outstanding’. “I must give @AnthropicAI credit here: Opus4.5 is outstanding,” he’d posted on X last month. Google too has been using Anthopic’s models internally to code, with a Google Principal Engineer saying last week that Claude Code had done more in an than their team had achieved in a year.
But at least someone from Musk’s universe doesn’t seem to have taken kindly to their teams being blocked from using Anthropic’s models. “Time to ban Anthropic from X,” X’s product head Nikita Bier wrote on X in response to the report. As of writing, Anthropic’s X account was available on X as usual.
This isn’t the first time that Anthropic has cut off access to its models to certain companies. Last year, Anthropic had cut access to its models to Windsurf after there were reports that it had been acquired by OpenAI, presumably not to give OpenAI access to data around how its models were being used. Such disruptions could cause AI model companies that compete with Anthropic to think twice about using its services, and possibly hasten the creation of similarly strong models at their own organizations. But these reports are also a big endorsement for Anthropic’s coding products — with everyone from Google to xAI using them, they do seem to be a cut above the rest in terms of raw ability and usefulness.