A Comprehensive Compilation of Reliable Narrations · Hadith 357 (#Ḥadīth #2)

[2/249] الكافي: علي بن محمد، عن محمد بن علي بن بلال قال: خرج إلي من أبي محمد عليه السلام قبل مضيه بسنتين يخبرني بالخلف من بعده، ثم خرج إلي من قبل مضيه بثلاثة أيام يخبرني بالخلف من بعده

2. [2/249] al-Kafi: Ali b. Muhammad from Muhammad b. Ali b. Bilal who said: There came to me from Abi Muhammad [al-Askari] عليه السلام [a letter] informing me of the identity of the successor after him two years before his [al-Askari’s] death. Then there came to me [a letter] informing me of the successor after him three days before his death.

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).