Upward agreement and syntactic counterfeeding in Lubukusu

What are the constraints on agreement, and how does it interact with other syntactic operations? Recent studies suggest that syntactic dependencies are tier-based strictly local (TSL) over Minimalist Grammar derivation trees, a computationally restrictive model which closely fits many aspects of the formal typology (Graf 2022, Hanson 2025). Using this framework, I provide an analysis of upward complementizer agreement in Lubukusu (Diercks 2013), and show that it correctly predicts lack of agreement with hyperraised subjects without any additional assumptions. I argue further that the phenomenon should be understood as a kind of syntactic counterfeeding, which together with the existence of feeding, bleeding, and counterbleeding, suggests the need for a syntactic framework which can handle variable operation ordering.