SEATTLE — Google fired its opening salvo in what is expected to be a protracted antitrust fight with four dozen states, demanding more protections before it hands over confidential business documents sought by investigators.

In a petition filed on Thursday in Texas state court of Travis County, Google, along with its parent company Alphabet, sought a protective order against Ken Paxton, the attorney general of Texas, who is spearheading the multistate antitrust investigation into the company.

The petition said Mr. Paxton had not provided sufficient safeguards for how his office shares Google’s sensitive business documents with outside consultants to the investigation. Google said some of those outside consultants were also working for competitors or complainants.

It is first legal challenge made by Google since the attorneys general from 48 states as well as the District of Columbia and Puerto Rico said in September that they were starting an antitrust investigation into the market power and corporate behavior of Google, with Mr. Paxton taking the lead.