A lawyer for Twitter owner Elon Musk accused Microsoft of misusing the service’s data and demanded an audit from the software giant.

The letter primarily addresses a seemingly narrow set of alleged infractions by Microsoft in drawing information from Twitter’s database of tweets. But the move could foreshadow more serious developments. Musk has previously accused Microsoft and its partner OpenAI in a tweet of “illegally” using Twitter data to develop sophisticated AI systems such as ChatGPT.

“ Lawsuit time,” Musk wrote in that April tweet.

But the letter, signed by Musk lawyer Alex Spiro, tiptoed around that concern. It noted that Microsoft's agreement with Twitter barred it from overuse of the service's data such as exceeding “reasonable request volume" or “excessive or abusive usage.” Spiro then noted that “despite these limitations,” Microsoft had retrieved more than 26 billion tweets in 2022 alone.

He provided no context for those numbers. The process of training AI systems requires enormous amounts of data such as written text, which AI algorithms scour for patterns that the AI can use to make sense of language and large bodies of knowledge.

In other respects, the letter primarily laid out a series of vaguely worded allegations. For instance, it noted that while Microsoft was required to inform Twitter about its intended use of the data, it failed to do so for six of the eight Microsoft apps that drew on information from the Twitter database.

Similarly, the letter asserted that at least one Microsoft app had supplied Twitter data to a number of virtual locations that “reference a government entity or agency.” That apparently violated Microsoft's agreement with Twitter, the letter stated, which prohibited the company from retrieving Twitter data “on behalf of ‘any government-related entity’” without first notifying Twitter.

The letter stated that Microsoft had failed to provide such notification.

Microsoft spokesman Frank Shaw provided a statement noting that Microsoft will review questions raised by the letter and then will “respond appropriately.” The statement added that “we look forward to continuing our long term partnership” with Twitter, which it did not refer to by name. Shaw declined to address specifics from the letter.

Spiro's letter demanded that Microsoft describe in detail the Twitter data it possesses or has previously destroyed, the purpose for each of its apps that drew on Twitter information, and any government entities that used these Microsoft apps and whether they received data from Twitter's database.