The full-length version of The Client Brief best practice guide. Produced by the four main agency and client trade bodies (IPA, ISBA, MCCA and PRCA), The Client Brief covers three main areas: Why write a brief. The principles behind a good brief. What a good brief should contain. These new guidelines come as a result of research undertaken by the industry in March 2003 which showed that the current briefing process is far from satisfactory with clients sometimes using the creative process to clarify their strategy or relying on their agency to write it.