Pen-based user interfaces which leverage the affordances of the pen provide userswith more flexibility and natural interaction. However, it is difficult to construct usable pen-baseduser interfaces because of the lack of support for their development. Toolkit-level support has beenexploited to solve this problem, but this approach makes it hard to gain platform independence,easy maintenance and easy extension. In this paper a context-aware infrastructure is created,called WEAVER, to provide pen interaction services for both novel pen-based applications andlegacy GUI-based applications. WEAVER aims to support the pen as another standard interactivedevice along with the keyboard and mouse and present a high-level access interface to pen input.It employs application context to tailor its service to different applications. By modeling theapplication context and registering the relevant action adapters, WEAVER can offer services,such as gesture recognition, continuous handwriting and other fundamental ink manipulations, toappropriate applications. One of the distinct features of WEAVER is that off-the-shelf GUI-basedsoftware packages can be easily enhanced with pen interaction without modifying the existing code.In this paper, the architecture and components of WEAVER are described. In addition, examplesand feedbacks of its use are presented.