As we know shias do believe that prophet (sallalahu alaihi wa ala alihi wa sallam) appointed 12 imams. Many of them believe that they were named by him.
al-Husayn ibn Sulaiman al-Hilli in “Muhtasar basair ad-Darajat” (p 14) narrated that when Muhammad ibn al-Hanafiyah disputed on Imama with Ali ibn Husayn, imam Zaynalabidin said to him:
وجاءت في كتاب مختصر بصائر الدرجات هكذا : إن الله ـ تبارك وتعالى ـ لما صنع الحسن مع معاوية ما صنع ، أبي أن يجعل الوصية والإمامة إلا في عقب الحسين
When al-Hasan (alaihi salam) maintain with Moawiyah what he has maintain, Allah Tabaraka wa Taala made al-Wasiyah and al-Imama in the posterity of no one other than al-Husayn.
This report came to us via this chain:
أحمد وعبد الله ابنا محمد بن عيسى عن الحسن بن محبوب عن علي بن رئاب عن أبى عبيدة الحذاء وزرارة بن اعين عن أبي جعفر
1 – st link of chain: Ahmad and Abdullah sons of Muhammad ibn Isa. Ibn Dawud al-Hilli and Najashi described Ahmad as shaykh and faqih of Qum in his time.
2-nd is al-Hasan ibn Mahbub, who was thiqat and from ashabul Ijma. And that mean if report authentic till him, its authentic.
3-d is Ali ibn Raba and he was thiqat, as said ibn Dawud al-Hilli.
4-th are Abu Ubaydah al-Hazaa and Zurara. No need to introduce Zurara.
As we can see all narrators are upright in accordance to shia books.
What benefits we can get from this report?
1) Nor in the time of prophet (sallalahu alaihi wa ala alihi wa sallam), neither in the time of Ali or Hasan (radi Allahu anhum) there was no such thing like list of appointed 12 imams.
2) From this report is clear that only after al-Hasan made treaty with Muawiyah, Allah put wasiyah and imama in the posterity of al-Husayn.