Caise, a collaborative software engineering architecture, provides extensible real-time support for collaboration between participating tools and users. The architecture maintains a semantic project model constructed incrementally from software artifacts as they are developed; this model is used to determine the impact of changes at a semantic level. This information is relayed to developers, providing them with awareness of others’ locations, and alerting them to potential conflicts and the need for closer collaboration. We use examples from Caise-based tools to illustrate the potential of real-time collaborative software engineering to enhance awareness of other developers’ actions.