Al-Tabari did not write as Bukhari wrote. He did not condition a report on being sahih before he set it down. He set it down with its chain. The criticism, he said, is in the names. A reader who treats every line in the Tarikh as “what happened” has not read the introduction.
Whatever in this book of mine is a report that is found objectionable — let the reader know it did not come from us. It came from some who transmitted it to us. We have only delivered it as it was delivered to us.
al-Tabari, introduction to the Tarikh
This is the key of the whole work. He is a trustee of transmission, not a guarantor of every story.
How to weigh this
Three lamps on every page of Nur’s reader: (1) Quran first, where the Quran speaks. (2) A sahih report from the Six, where one exists. (3) Tabari’s akhbar, with the chain named and the grade not assumed. If only the Tarikh carries a tale, we say so.