Abstract A prototype expert system is described that advises end-users in the selection of a suitable development environment for small- to medium-scale expert system applications. The system, running on a microcomputer, assesses the suitability of an application as a whole for expert systems techniques and recommends the five ‘best’ products from its knowledge base of 42 products. The paper takes a case-study approach, using the system itself as a recursive discussion example, applying some of the concepts involved in building an expert system. It describes the operation of the system and suggests improvements; it includes a feature list for classifying expert system shells.