Performance evaluation is one of the major factors that determine the growth and development of any organization. Competent and hardworking employees are identified proper appraisal, and promotion and gratuity are justly applied. Lack of clarity of performance metrics and bias create improper appraisal in organizations, with evaluation process mostly inconclusive, incomplete, and unfair, affecting the effectiveness of the result. This study, therefore, focused on developing a model and application towards achieving a staff-centric, task-centric and environment-centric computer-based appraisal system. In developing the proposed system, the spiral model of the Software Development Life Cycle was adopted. The software development environment consists of Netbeans Integrated Development Environment, Hypertext Mark-up language, MySQL, MySQL DB connector, Apache and PHPmyAdmin. The metrics that were used by the system to evaluate performance include attendance, employee responsiveness, punctuality and projects. The model was created and an agent-based performance evaluation application was developed as an instantiation of the model. The system revealed employee strengths and weaknesses regarding execution of a particular project.