Based on an empirical study of the citizen science initiative Biodiversity Galiano and the biodiversity data collection platform iNaturalist, this paper presents an analysis of the meeting between the technology adaptation processes of grassroots communities and the contemporary software development process. Where previous work has developed a theoretical account of how grassroots communities form around shared activities and assemble ecosystems of tools, we investigate how the contrasting means and ends of end-users and software developers shape and constrain this assembly process. We apply the activity-theoretical concept of Common Interactive Objects to analyze the role of iNaturalist as a key tool in the artifact ecology of Biodiversity Galiano on the one hand, and as the central product of its developers on the other. We find that this dual role for the platform creates tensions that both motivate and constrain the adaptation work within Biodiversity Galiano, and argue that in this respect our case is reflective of the general experience of grassroots communities who rely on platform software.