During the reign of Emperor Ruizong of the Tang Dynasty, a man named Xue Deng from Yixing in Changzhou once served as an imperial advisor.
This man had a vast knowledge of literature and history, and whenever he discussed events of past dynasties, he would cite numerous sources to explain his points thoroughly, making the examples he referenced seem as vivid as if he had witnessed them himself.
He was equally renowned as Xu Jian and Liu Zixuan, maintaining a close bond with frequent visits and exchanges between them.
During the Tang Dynasty, the imperial advisor Xue Deng submitted a memorial to the emperor criticizing the lax standards in selecting talented officials and the overemphasis on flowery poetry. He cited the words of the official Li E, who had harshly criticized the three Cao fathers and sons—Cao Cao, Cao Pi, and Cao Zhi—for their corrupting influence on literary culture.
He said, "The three founders of the Wei state were especially fond of poetry and rhapsodies, neglecting the great principles of governance. Their obsession with trivial literary skills resulted in endless pages filled with nothing more than descriptions of moonrise and moonset, thick and thin dew, and piles of writings on desks and stuffed into boxes were merely sighs over gentle and fierce winds, gathering and dispersing clouds."
While his views certainly have merit, his critique of the Cao family's poetry is rather unfair.
"The idiom 'carving insects as a petty skill,' also written as 'carving insects as a minor art,' shares the same meaning as 'carving insects and seal script.' It is used to describe an insignificant skill. Later, it mostly refers to the skill of writing poetry and prose."
Source: *Old Book of Tang*, "Biography of Xue Deng"
Meaning of the Idiom: Later, the Chinese idiom "雕虫小技" came to describe an insignificant skill.