The paper presents a coding scheme for design protocol analysis of collaborative sessions supported by Augmented Reality. It maps verbal interactions during creative sessions, so as to distinguish codesigners' intentions and the related contents characterizing the characteristics of the design proposal in terms of items and related parameters. Three different co-creative sessions and a tailored metrics allowed for checking the coding scheme effectiveness, showing good mapping capabilities and versatility of application also to compare similar sessions carried out with and without AR support.