One of my PhD students, Paolo Tell, and I have been working on exploring the viability of using activity-based computing (ABC) paradigm for designing and developing the next generation of tools for supporting Global Software Engineering. The fundamental assumption of our research on applying ABC for building GSE tools is that a large majority of the GSE tools have been built based on desktop metaphor, which has several inherent limitations. Hence, there is an imminent need of new design and development paradigms for building GSE tools. We have achieved initial success with building prototype platform called ABC4GSD, which can enable tools activity aware. However, we realised that there is a need of sound theoretical foundation based on activity theory for addressing challenges faced by tools in GSE. We have recently reported our efforts aimed at building theoretical foundations for applying activity theory to GSE. This ICGSE paper analyzes and explains the fundamental concepts of activity theory, and how they can be applied by using examples of software architecture design and evaluation processes. This paper also outlined the data model and architectural support required for applying activity theory in building tooling infrastructure for GSE. Comments and suggestions are welcome.