For CoastAdapt to be useful and used, it needs to be relevant, accessible and authoritative. As NCCARF scoped the tool in late 2014 and early 2015 we undertook a comprehensive communication and engagement process to understand what ‘relevant’, ‘accessible’ and ‘authoritative’ means for coastal decision makers. We consulted with more than 600 individuals and groups that have influence in the coastal zone.  Activities included a kick-off meeting, a series of regional consultation meetings (300+ people), and an online survey (299 responses).  Key findings that helped to guide the development of the tool include:  the need to build capacity around understanding future projections of sea level rise and climate impacts; the need to support consistency across many areas of decision making; the ability for decision maker to persuade and engage others about potential adaptation options.  Above all the tool needed to ‘make their life easier not harder’.  Strategies by NCCARF to ensure the tool is fit for purpose is to use effectively our three governance committees  for advice on tool content, as well as seek specialty expertise in ‘user experience’ to ensure the website navigation is helpful.  We also established an advisory group of ‘tool development partners’ which has been invaluable in providing grassroots advice on all facets of the tool.