The MAterials Simulation Toolkit (MAST) is a workflow manager and post-processing tool for ab initio defect and diffusion workflows. MAST codifies research knowledge and best practices for such workflows, and allows for the generation and management of easily modified and reproducible workflows, where data is stored along with workflow information for data provenance tracking. MAST is available for download through the Python Package Index, or at https://pypi.python.org/pypi/MAST , with installation instructions and a detailed user’s guide at http://pythonhosted.org/MAST . MAST code may be browsed at the GitHub repository at https://github.com/uw-cmg/MAST . [ABSTRACT FROM AUTHOR]