This paper presents an automated software tool SQUARE (Software QUality and ARchitecture modelling Environment). It is designed and implemented to support the analysis of software quality from software architectural designs. The tool is based on a modelbased method and follows a structured process to systematically derive quality models from software architectural designs by adapting and applying the principles of system hazard analysis. Through identification of potential quality hazards and their consequences, the quality related properties of the components and connectors and the causal relationships between them are derived and then translated into a quality model represented in a graphical notation. The tool enables automated analysis of the quality models in the graphical notation to recognize a number of types of software quality features including quality sensitive components, quality risks and quality trade-off points, etc. A case study with a real e-commerce system is also r...