Cloud diaries were journals used by Chiss as diaries and artistic canvases depicting nature. The writing in cloud diaries was stylized into small features that composed the details of the drawing. Yomie described the Agbui's manipulations in her cloud diary and was killed by Haplif to silence her revelations.
Yomie, a Chiss female, kept a cloud diary when traveling with her betrothed Yoponek, which she continued writing after joining a group of Agbui led by Haplif around 18 BBY. The Agbui claimed to be "cultural nomads", but were attempting to subvert the Chiss nation on behalf of an expansionist empire.
Haplif hoped to read Yomie's cloud diary to learn her motivations to better manipulate her, but she did not let him. When Yomie left the Agbui's starship, she took her diary so Haplif could not read it. After spending several weeks bird-watching on the planet Shihon, Yomie deduced that the Agbui possessed telepathy and were manipulating the Chiss. Yomie recorded everything she knew about the Agbui in her cloud diary. To prevent that knowledge's spread, Haplif murdered Yomie, dumping her and her diary into the vacuum of space.
A cloud diary appeared in flashbacks in Timothy Zahn's 2021 novel Thrawn Ascendancy: Greater Good.