Hadeeth Qudsi is a narration from the Prophet Muhammad (SAWA) which is supposed to be from Allah (SWT) in its meanings and from the Prophet (SAWA) in its wordings. Hadeeth Qudsi is not like Quran because the whole Quran is absolutely authentic and every letter in Quran is from Allah The Glorious in the meaning and the words, while Hadeeth Qudsi is a narration which must be authentic and if it is proves authentic, then the meanings id from Allah but he wordings is from the Prophet .
As every narration from the Prophet (SAWA) needs to be studies properly by specialized scholars in its contents (Matn) and narrators who must be reliable. The scholars in Hadeeth study every narration, to be sure that its content does not contradict the facts mentioned in Quran and authentic Hadeeths, as well as the narrators must be reliable and trustworthy.
Hadeeth Qudsi is narrated in Shia books of Hadeeth as well as Sunni books of Hadeeth.
The prominent Shia scholar Al-Horr Al-Aamily has compiled a well known book in Hadeeth Qudsi called Al-Jawahir Al-Saniyyah Fil Ahadeeth Al-Qudsiyyah.
Our scholars take from the narrations only the authentic ones, just like the narrations in every subject.