Engagement practitioners (EP) work in diverse settings for UK public service
providers in the UK to increase citizen participation in decision-making for those
services. They use participation tools, including pro-formas and worksheets to aid participatory activities. We identify a tension between participation tool literature advocating for design of tools to disseminate participation methods to EPs, and tooluse literature demonstrating how tools can be modified in use. We ask how are participation tools used by EPs? What roles do instruction and flexibility of use play? How can EPs develop their participation practice through tool-use; and, how can those insights inform future tool design? In answer, findings and insights are presented from interviews with fifteen UK-based EPs conducted between October 2017 and May 2018. Three recommendations are made for the design of participation tools. This research has implications for social designers working in areas including participatory design, co-design or service design contexts.