The State Department, under Secretary Hillary Rodham Clinton, created an arrangement for her longtime aide and confidante Huma Abedin to work for private clients as a consultant while serving as a top adviser in the department.

Ms. Abedin did not disclose the arrangement — or how much income she earned — on her financial report. It requires officials to make public any significant sources of income. An adviser to Mrs. Clinton, Philippe Reines, said that Ms. Abedin was not obligated to do so.

The disclosure of the agreement that Ms. Abedin made with the State Department comes as her husband, former Representative Anthony D. Weiner, a Democrat, prepares for a mayoral run in New York City. Politico reported the arrangement on Thursday afternoon.

Ms. Abedin declined a request for an interview, but the picture that emerges from interviews and records suggests a situation where the lines were blurred between Ms. Abedin’s work in the high echelons of one of the government’s most sensitive executive departments and her role as a Clinton family insider.