Ethnographic studies of legal materiality and the bureaucratic mundanities of law often juxtapose their richly empirical approach to the material assemblages of law with the ‘grand talk’ and conceptual abstractions of law. This article considers the intersection of formal legal discourse and the mundanity of bureaucratic practice through an examination of two judicial opinions concerning the legal significance of the Bates number, a sequential digit inscribed onto documents produced in US pretrial discovery. Through this analysis, the article both illustrates the Bates stamp’s role in the material constitution of law, and offers a reminder that the stories law tells about its own materiality can offer insights into, and enact and extend, the sociolegal agency of bureaucratic tools.