One embodiment of the present invention provides a system for providing context-based web services for a user. During operation, the system receives a sentence as input from a user. The system performs natural language processing on the sentence to determine one or more parameters. The system retrieves data from a foreground knowledge graph containing contextual data for the user and from a background knowledge graph containing background information corresponding to the parameters. The system determines a set of arguments based on the parameters and/or data from the foreground knowledge graph and/or data from the background knowledge graph. The system then selects an action module based on results of the natural language processing and/or the set of arguments. The system passes the arguments to the action module. The action module then uses the arguments to respond to a question or interact with web services to perform an action for the user.