Except that the Japanese Naval Code wasn’t broken at that point. Their diplomatic code had been but the Japanese military didn’t trust the diplomats or share their plans with them.
A useful "primary source" suggested can by found at www.archive.org. Generally given as the "Congressional Report on the Pearl Harbor Attack" - these are PDF files (often quite large).
From Volume 37, pages 1062-1063, at times noted as 37PHA1062-1063, are "Naval Message - Navy Department" copies. Note the dates, as these might be of importance.
A. If the IJN was operating under "strict" radio silence, where did these messages come from? B. On page 1063, note message beginning "Recent developments from RI X" ... and ending with "Following from CI translation today ..."
N.B., Within these Congressional Reports are several "Exhibits" that might be of help. Specifically, Exhibit No. 151. There questions might be raised as to the meaning of "translations" and "exchange" of technical information.
To close, a recent paper by Burtness and Ober might be of interest:
"Provocation and Angst: FDR, Japan, Pearl Harbor, and the Entry into War in the Pacific" The Hawaiian Journal of History, Volume 51, (2017), pages 91-114.
Also, regarding radio silence:
The IJN, at the time of Pearl Harbor, operating standard was:
(1) Very Strict Radio Silence (TE-SE-KA), (2) Strict Radio Silence (TE-KE-KA), and (3) Radio Silence (TE-TSU-KA).
N.B., Various translations of "Strict" exist in Japanese, and true copy of SRN-116866 (from 25Nov1941). The true copy of SRN-116866 has three paragraphs - all allow radio transmission.
Just a question - Who won WWII?