CIRCLES aims to discover and translate innovative microbiomes-tailored circular actions into concrete applications that will ultimately enhance EU food system performances and their overall sustainability. The setup of real-world labs in the field of 6 food systems relevant to the EU market – tomatoes, spinach, poultry, pigs, Atlantic salmon and seabream aquacultures – will, first, enable CIRCLES to increase knowledge on the importance of food system microbiomes as determinants of productivity, quality, safety and sustainability. This discovery phase will nurture the design and implementation of food system-specific microbiomes-tailored circular actions. Relying on an integrative usage of different Smart Microbiome (SM)-modulators, circular actions aim to optimize the microbiomes of food systems, from farm to fork, for an overall improvement of food system performances. The effectiveness of actions will then be tested in the labs in the field. This real-world validation phase will allow CIRCLES to translate the project results into concrete products, applications, procedures and tools, ready to be exploited and communicated to penetrate the EU market. In particular, CIRCLES will conceptualize and create SM-food systems for the 6 CIRCLES food chains, defined as food systems with optimized microbiome configurations. CIRCLES will also provide innovative, newly defined SM-food products, as foods derived from the SM-food systems and certified by Microbiome Transparent (MT)-labels. Finally, a vast panel of food system-specific SM-modulators will be provided as new agro-biotech applications to be integrated into circular actions to reach the status of SM-food system. In conclusion, the conceptualization, creation, and dissemination of SM-food systems, as well as all connected procedures, products, and tools, will allow CIRCLES to endow the EU food systems with new, cost-effective commercial applications for improved productivity, quality, safety and sustainability.