This paper is meant to be an contribution to the current debate on the scope and accountability of grammatical description by a critical examination of features of the systemic-functional model. As to scope, I consider to what extent this grammar can actually account for language use in text. I argue that the semantic functions which are specified in the separate components of systemic-functional grammar combine pragmatically under variable conditions of interpretation which will aways elude grammatical analysis, and that although it is possible to analyse text as manifesting linguistic categories, the interpretation of text as the realization of this categories in discourse is a pragmatic beyond the scope of grammar. This means that you can make use of grammatical description, and therefore make it useful, but use and usfulness cannot be intrinsic design features of the description, and cannot be adduced as measures of its validity.