This chapter introduces the CASTROFF framework as a structured, professional standard for designing, analyzing, and evaluating prompts in human–AI interaction. It addresses the lack of consistency in current prompting practices and argues for a shared vocabulary to support reliability, auditability, and professional use. The framework defines eight interrelated dimensions; Constraints, Audience, Structure, Tone, Role, Output format, Focus, and Function, each shaping how prompts are interpreted and executed. The chapter examines how constraints establish boundaries, how audience and tone guide communicative alignment, and how structure and format improve clarity and usability. It distinguishes focus from function to clarify the difference between content emphasis and communicative purpose. Each dimension is explored as both a technical control and an ethical consideration in high-stakes environments. Practical guidance, including diagnostic strategies and refinement heuristics, demonstrates how prompts can be evaluated and improved systematically. The framework is positioned as an extension of prompt anatomy, enabling teaching, standardization, and cross-domain application. Emphasis is placed on transparency, responsibility, and the professionalization of prompt design. Ultimately, CASTROFF is presented as a foundational model for creating precise, reliable, and purpose-driven AI interactions.