This paper describes Cape, a programming environment combining Clips And Perl with Extensions. Clips is an efficient and expressive forward-chaining rule-based system with a flexible object system. Perl is a popular procedural language with extremely powerful regular expression matching facilities, and a huge library of freely available software. Cape closely integrates these languages, and provides extensions to facilitate building systems with an intimate mixture of the two. The paper describes the facilities Cape offers programmers and the demonstration systems and “component applications” distributed with it. The use of the system is then discussed with reference to dime (Distributed Information Manipulation Environment), a toolkit being developed to support identifying and coordinating the use of external knowledge sources. Finally, planned developments of the system are indicated.