In German, past participles not only occur in root position with a directive force, as in Stillgestanden! ‘Stop!’ lit. ‘stood still(ptcp)’, but also as performatives in responses: A: Du sagst also nichts zu Papi. ‘So you won’t tell dad.’ B: Versprochen! ‘I promise!’ lit. ‘promised(ptcp)’. Here B performs the speech act denoted by the verb by saying that it has been performed. The propositional argument of the participle (what is promised) is resolved contextually, and the agent and the recipient arguments are restricted to the speaker and the hearer, respectively. This article presents a syntactic analysis of this rarely studied phenomenon, arguing that the construction with a performative participle is not ellipsis but an IP with a participial head and null pronominal complements. The syntactic analysis is formalized within Lexical-Functional Grammar. A pragmatic analysis is proposed arguing that the performative participle in its core use alternates with Yes! to express agreement with an assertion or compliance with a request, that is, to express consent to the effect that a proposition p may safely be added to the Common Ground. This analysis is cast within the dialogue framework of Farkas & Bruce (2010) and extended to response performative participles in monological uses.*