GEN1438 A child is forbidden to tell his parents derogatory information about his brothers and sisters before he himself has admonished them.   The Chofetz Chayim notes that Yosef did not relate derogatory information about his brothers to anyone else besides their father.   Furthermore, his intentions were constructive and not malicious.  Nevertheless, Yosef’s report was improper, since he should have admonished his brothers and tried to correct their apparent misdeeds before speaking to his father about them.  Had he reproved his brothers, they would have been able to show him that he was mistaken (see Sifsai Chachomim).  Because he failed to go directly to them first, Yosef was punished (Rashi).   Shmiras Haloshon 2:11).   PLYN 109