Generally speaking, Uṣūl al-kāfī contains traditions that deal with epistemology, theology, history, ethics, supplication, and the Qurʾān.

According to the Imami scholar Zayn al-Dīn al-ʿĀmili, known as ash-Shahīd ath-Thāni (1505–1559 CE, 911–966 AH), who examined the asanād or the chains of transmission of al-Kāfi traditions, 5,072 are considered ṣaḥīḥ; 144 are regarded as ḥasan ('good'), second category; 1,118 are held to be muwathaq ('trustworthy'), third category; 302 are adjudged to be qawi ('strong') and 9,485 traditions which are categorized as ḍaʿīf ('weak').

I hope it is as you desired.Imam Khomeini (a prominent 20th century Shī‘ah scholar and statesman) said:[7][full citation needed] Do you think it is enough [kafi] for our religious life to have its laws summed up in al-Kāfī and then placed upon a shelf?The general idea behind this metaphor is that Khomeini objected to the laziness of many ignorant people who simply kept al-Kafi on their shelf, and ignored or violated it in their daily lives, assuming that they would somehow be saved from Hell just by possessing the book.

Khomeini argued that Islamic law should be an integral part of everyday life for the believer, not just a stale manuscript to be placed on a shelf and forgotten.

The irony of the allusion is telling; Khomeini implicitly says that al-Kāfī (literally 'the Sufficient') is not kafi ('enough') to make one a faithful Muslim or be counted among the righteous, unless one uses the wisdom contained within it and acts on it.

Khoei points this out in his Mu‘jam Rijāl al-Hadīth, or Collection of Men of Narrations, in which he states:[8] Shaykh as-Sadūq did not regard all of the traditions in al-Kāfī to be Șaḥīḥ ['truthful']Scholars have made such remarks to remind the people that one cannot simply pick the book up, and take whatever they like from it as truthful.