This study investigated English as a Foreign Language (EFL) teachers' beliefs concerning the use of an AI grading tool (CoGrader) for essay scoring and feedback. The study also explored the factors which contributed to those beliefs. EFL teachers (n = 10) from public universities (n = 3) in Saudi Arabia participated in this study. The study employed a mixed-method approach with a quantitative questionnaire followed by qualitative interviews. The results were further conceptualized within the Activity Theory (AT) framework to ensure a better understanding of the interrelation of teachers' beliefs and factors influencing those beliefs. Findings indicated that CoGrader was perceived positively by the majority of the participant teachers as an assistant tool in scoring students' written essays and in providing feedback. However, the dependability of such AI scoring software is still in question and it was not accepted as a complete substitute for teacher grading. Teachers and teacher trainers are therefore advised not to neglect AI grading but to engage with cautious use of it.