It’s the American dream: We’re supposed to improve ourselves, get a better job, move on and up. But in too many instances, secret agreements between employers are stifling workers’ ability to parlay their hard work and experience into better-paying jobs and a chance to climb the career ladder.

On Thursday, the attorney general of Washington State, Bob Ferguson, announced that he had obtained agreements from seven fast-food chains, including Arby’s, Carl’s Jr. and McDonald’s, not to use or enforce “no poach” or “no hire” agreements. Under these arrangements, franchisees pledge not to hire job applicants who are current or recent employees of the company or any of its franchisees, without the approval of the applicants’ employers.

This crackdown on a widespread practice is a welcome development. But as Mr. Ferguson made clear in his announcement, he is still “investigating other corporate chains that utilize no-poach agreements.”

And he isn’t alone. On Monday, attorneys general from 10 states and the District of Columbia announced that they sent letters to Burger King, Domino’s, Dunkin’ Donuts and five other leading fast-food companies, seeking information about whether those companies use these no-poach or no-hire agreements.