The 106-page report, entitled “Planned in Plain Sight,” highlighted and added to evidence already uncovered by the now-defunct House Jan. 6 committee, news reporting and other congressional work to provide the most comprehensive picture to date of a cascading set of security and intelligence failures that culminated in the deadliest assault on the Capitol in centuries.

Aides said Senate staff obtained thousands of additional documents from federal law enforcement agencies, including the Justice Department, before drafting the report. It includes multiple calls for armed violence, calls to occupy federal buildings including the Capitol and some of the clearest threats the F.B.I. received but did little about — including a warning that the far-right group the Proud Boys was planning to kill people in Washington.