This talk demonstrates how tone can provide clues about large-scale grammatical architecture, drawing on primary data from Seenku (Mande, Burkina Faso). Seenku is a four-tone language, contrasting extra-low (X), low (L), high (H), and super-high (S) tones, which can combine to form many contour tones. Beyond the complexity of the tonal inventory itself, the language displays intricate tonotactics and grammatical tone processes that interact in complex ways. I focus here on three processes, whose interaction acts as a window onto the architecture of the grammar. First, a phonotactic restriction against H in word-final position in open class vocabulary triggers epenthesis of X, creating a H-X contour. Second, plurals are formed in part by tone raising, triggered by the suffixation of a [+raised] tone feature. Third, the tone of inalienably possessed nouns and irrealis verbs changes based on the tone of the possessor or the object of the verb, which I treat as construction-specific phrasal morphology. The interaction of these three processes points to systemic cyclicity, rather than cyclicity in the phonology proper: the possessor or object DP must undergo all tonal processes first, as the raised plural tone or epenthesized X can spread to the possessed noun or verb. Within the verb or possessed noun’s cycle, it must undergo construction-specific alternations before plural formation. The facts can be accounted for in a framework of cyclic spell-out, where more deeply embedded phases (the possessor or object’s DP) are sent to spell-out and receive morphophonological form before less deeply embedded phases (the overarching DP containing the possessed noun or the VP). Further, the order of processes within a cycle points to Morphology before Phonology in the computation of surface form. This approach fares better than alternatives, including cophonologies and Stratal OT. In sum, this talk provides an overview of Seenku’s complex tonology and demonstrates how tonal data can shed light on the architecture of grammar beyond their immediate domains (i.e. phonology, morphology).