What is the ruling on cracking knuckles inside and outside the mosque, and is there any authentic prohibition reported concerning that?

Cracking one's knuckles during prayer is considered makrooh (disliked) by the four schools of thought. Ibn Abidin explicitly stated its prohibition due to the warnings mentioned in the hadiths. Consensus has been reported regarding the dislike of cracking knuckles and interlocking fingers during prayer. As for outside of prayer, it is disliked by some scholars, while others have qualified it as permissible if there is no need for it. It is more appropriate to avoid it entirely unless there is a necessity.