David Sarrut, Nicolas Arbor, Thomas Baudier, Julien Bert, Konstantinos Chatzipapas, Martina Favaretto, H. Fuchs, Loïc Grevillot, Hussein Harb, Gert Van Hoey, Maxime Jacquet, Sébastien Jan, Yihan Jia, George C. Kagadis, Han Gyu Kang, Paul Klever, O. Kochebina, W. Krzemień, Lydia Maigne, Philipp Mohr, Guneet Mummaneni, V. Paneta, Panagiotis Papadimitroulas, Alexis Pereda, Axel Rannou, Andreas Resch, Emilie Roncali, Maxime Toussaint, Carlotta Trigila, Charalampos Tsoumpas, Jing Zhang, K. Ziemons, Nils Krah
We present GATE version 10, a major evolution of the open-source Monte Carlo simulation application for medical physics, built on Geant4. This release marks a transformative evolution, featuring a modern Python-based user interface, enhanced multithreading and multiprocessing capabilities, the ability to be embedded as a library within other software, and a streamlined framework for collaborative development. In this Part 1 paper, we outline GATE's position among other Monte Carlo codes, the core principles driving this evolution, and the robust development cycle employed. We also detail the new features and improvements. Part 2 will focus on the architectural innovations and technical challenges. By combining an open, collaborative framework with cutting-edge features, such a Monte Carlo platform supports a wide range of academic and industrial research, solidifying its role as a critical tool for innovation in medical physics.