The great development of the knowledge society on the Internet requires that Web information systems are adapted at runtime to user groups with common interests. Interface agents help us to observe and learn from user preferences making interfaces adaptable to user working habits. We propose an interface agent which works on Web interface based on COTS components, adapting the interface to the user needs or preferences. Our agent runs two main behaviors: observation behavior which analyses the user interaction on the interface and a second behavior which runs the adaptation actions to adapt the user interface at runtime
