Who is responsible for your acts?

Summary of pages (12 -13) from the book [1]

The Mutazila did not make God as the cause of all that happens in the universe. Humans are responsible for their own acts.

The Mu'tazila further claimed that this constantly created reality behaves according to known patterns of events or "nature" ('ada) on which human reasoning about the world is based.[1]

Sometimes, God allows Miracles to be perform by Prophets. According to them, this is the only exception to the rule. False Prophets do no perform real miracles because that would sabotage human rationality.

The Mutazila were faithful to the Islamic faith. They believe that reason can demonstrate the existence of God and that the revelation is advantageous to human rationality.

The biggest opposition to the Mutazilah came from the Hanbalite Sunnis (follower of Sunni Imam Ahmad ibn Hanbal).

The term Sunni or Sunnah wal-Jamaah came from two groups of traditional Muslim groups; the people of the Sunnah (ahl al-Sunnah) and the community (wa l-Jama'a).

from which the term "Sunni" is derived. 'Traditionalist (Hanbali) and rationalist (Mu'tazili) religious leaders also belonged to this broad and dynamic Sunni majority (though some Mu'tazili mutakallimun leaned toward Imami and Zaydi Shi'i political theologies). [1]

Reference
[1] Martin, Richard C, Woodward, Mark R and Atmaja, Dwi S. 1997. Defenders of Reason In Islam: Mu'tazilism and Rational Theology from Medieval School to Modern Symbol. Oneworld Oxford. Preface. ISBN 978-1851681471