In this paper we investigate cross-linguistic variation in the morphosyntax of copular clauses, focusing on agreement patterns in binominal structures [NP1 BE NP2]. Our starting point is the alternation between NP1 and NP2 agreement, which arises both within and across languages. This alternation is typically taken to be confined to specificational (i.e. inverted) clauses, and previous analyses have strongly identified NP2 agreement with the syntax of inversion. However, we show that NP2 agreement is attested in a broader range of contexts, specifically in (assumed identity) equative structures, suggesting that it should not be correlated with specificational syntax. We present contrasting data from two languages – Persian and Eastern Armenian — for which the syntax of copular clauses is understudied. Whereas in Persian we see NP2 agreement in specificational structures but NP1 agreement in assumed identity equatives, in Eastern Armenian both types of structure yield NP2 agreement. We argue that the contrast between Persian and Eastern Armenian supports an approach that takes the NP1–NP2 alternation to arise as a phi-sensitivity in the probe–goal mechanics of Agree in a minimalist framework. Under this view, NP2 agreement is independent of syntactic inversion and is the result of the probe structure being articulated in such a way that certain NPs fail to Agree.