WASHINGTON — Maria Butina, the Russian woman accused of running a secret campaign to influence powerful American conservatives, has agreed to plead guilty to conspiring to act as a foreign agent, bringing to a close a case that had drawn headlines with prosecutors talking of a sly seductress who traded sex to further the aims of her spymasters in Moscow.

But in court papers laying out the plea deal, the portrayal of Ms. Butina is far tamer than the narrative the government put forward after her arrest in July. The latest filings make no mention of the most salacious accusations against Ms. Butina — that she used sex as spycraft — and she instead comes across as the tool of powerful men who helped her to infiltrate the National Rifle Association and the Republican Party.

Prosecutors even appear to have backed off the accusation that Ms. Butina used a graduate program at American University in Washington merely as a cover to enter the United States. “All available evidence indicates that Butina had interest in a graduate school education,” prosecutors say in a footnote.

The deal, which now must be approved by a judge, stipulates that Ms. Butina must cooperate with federal, state and local authorities in exchange for what could be a short prison term, or possibly a release after having already spent five months in jail. As a felon, she will most likely be deported after her release, as was made clear in court filings laying out the deal that were obtained by The New York Times.