Abstract Background Evidence syntheses are essential to the creation of evidence-based guidelines that guide health care. Findings from our recent mixed methods systematic review (MMSR) identified no gold standard format for communicating summaries of evidence syntheses to guideline development groups. This is important as these groups are comprised of patients, healthcare providers, policymakers, etc., who all have different expertise, perspectives and priorities. Our overall aim is to develop evidence-informed prototype summary formats for use in guideline development. To inform this process, we held online co-design focus group workshops shaped by findings from our MMSR. Methods We held six focus groups with 30 participants involved in developing guidelines and/or evidence synthesis (February - March 2023). The topic guide was informed by the MMSR -- focusing on recommendations with mixed methods support, ≥3 supporting studies, and those prioritised by an expert advisory group through a pragmatic prioritisation exercise using the MoSCoW method (Must, Should, Could, and Will not haves). Focus groups were recorded and transcripts were analysed using a directed content analysis. Results Participants suggested a “less-is-more” structured approach that minimises methodological steps and statistical data, promoting accessibility to all audiences by judicious use of links to the full technical report. They emphasized the importance of concise consistently-presented formats which emphasize key messages, flag readers to indicators of trust in the producers (i.e., logos, websites, and conflict of interest statements), and highlight the quality of evidence. Conclusions Project findings are informing the creation of accessible and actionable guidance on best-practices for creating summary formats. Next steps involve user-testing prototype formats through semi-structured interviews which will then be integrated into the National Clinical Guideline development process in Ireland. Key messages • Co-design workshops delineated key aspects of effective and acceptable evidence synthesis summary formats to help create reproducible format templates for use in clinical guideline development. • Creating summary formats accessible to all guideline development group members will promote better communication and translation of research evidence into recommendations and practice.