DOGE is an agency, it took over the digital services agency that existed before.[1]. Obama had created the original agency, not Congress, so Trump had the ability to change it.

"The United States Digital Service is hereby publicly renamed as the United States DOGE Service (USDS) and shall be established in the Executive Office of the President."

And I’m not sure why you think a “congressional mandate” is required for the executive to do things, it’s not. Especially for an agency that a former President created on his own.

As for data access, my understanding is the digital services agency already had data access to other agencies through pre-existing agreements (it goes back to the original mandate to fix the Obamacare website which required pulling data from numerous databases).

[1]https://www.whitehouse.gov/presidential-actions/2025/01/esta...