This article introduces a novel approach to addressing challenges in Program Increment (PI) Planning within Agile methodologies and large-scale software development. Our research develops a metamodel and framework to formalize the PI Planning domain, enabling systematic modeling and effective impact analyses. PI Planning is crucial in Agile software development, helping teams align their efforts towards a common goal. By breaking projects into manageable increments, teams maintain flexibility and adapt to changing requirements. Increment planning promotes regular inspection, adaptation, continuous improvement, and early issue identification. It enhances transparency, collaboration, and stakeholder engagement, leading to successful, customer-focused software development. Despite its importance, organizations struggle to model the PI Planning process and analyze its impact on project outcomes. Key contributions include: • Metamodel Design: A detailed metamodel capturing essential structural concepts, relationships, and constraints within the PI Planning domain, providing a foundation for modeling PI Planning processes. • Framework Design: A practical framework leveraging the metamodel, offering multiple perspectives on the PI Planning process. This framework enables stakeholders to create tailored views and conduct impact analyses, supporting informed decision-making.