Cultural-historical activity theory (CHAT) offers veterinary and animal-science educators a powerful way to design learning as collective, tool-mediated transformation of practice rather than as individual acquisition of decontextualized knowledge. Yet CHAT’s “rules” component often remains a descriptive category (codes, policies, conventions) rather than a designable mechanism that can be deliberately cultivated through pedagogy. This essay argues that logic and rhetoric can be integrated into a coherent philosophical component—mediated practical reason—that strengthens activity-theory-oriented educational models applied to veterinary and animal sciences. The integration proceeds through argumentation theory: logic contributes inferential accountability (warrants, rebuttals, standards of evidence), rhetoric contributes audience-orientation, value articulation, and trust-building required for coordinated action, and dialectical norms constrain persuasion ethically. On that basis, the essay proposes a principled re-specification of the activity system: substitute the “rules” node with persuasive media, understood as the material–semiotic infrastructures (genres, protocols, dashboards, rubrics, narratives, deliberative formats) through which norms are articulated, negotiated, and legitimated. The substitution does not deny the existence of laws or professional standards; it makes explicit how those standards enter practice and become actionable. Finally, the essay derives design principles and examples aligned to competency-based veterinary education and workplace learning: assessing argument quality within entrustable professional activities, designing boundary objects for One Health collaboration, and teaching rhetorical ethics as an explicit professional competency.