Urban agriculture and its potential contributions to a sustainable food system have been on Brussels' agenda for more than a decade. Launched in 2016, Brussels food strategy, the Good Food, is currently undergoing a reform, passing from a "Sustainable food system" focus to an Agroecology focus. Consequently, the administrations in charge -Bruxelles Environnement and Bruxelles Economie et Emploi -struggle to refine this new vision, facing the fuzziness around the normative concepts of Sustainability and Agroecology. Through the Good Food co-construction process, those administrations are having a hard time trying to arrange discordant points of view and facing different levels of participation among stakeholders. Researchers of the Agroecology Lab have actively contributed to the Good Food's vision process via a close dialogue with food policymakers and its stakeholders, especially urban farmers. Those discussions between the various stakeholders have fueled research proposals to enhance the transition process in Brussels Food Policy. This paper focuses on how researchers who support civil society dynamics -particularly through participatory action research methodologies -can play a crucial role in fostering public policies in general, and Brussels Food Policy in particular. Sometimes influenced, often influencers, how do these "bridgers" (also known as knowledge brokers or boundary workers) contribute to transition processes and help build collective innovation capacities? Throughout a process of reflexivity, researchers' posture is spelled out, in order to assess how both posture and process evolved and interacted.