Cities are particularly vulnerable to the consequences of climate change. Adaptation is therefore of high urgency. Architects and Urban Designers can play a key role through their actions, but adaptation is still little integrated in current design practices. Evaluation tools have been developed to assess the environmental quality of urban projects (regarding energy consumption of buildings, most of the time), but are seldom used by practitioners. Those tools are often too specific for the multi-scale urban design project and the results they produce do not fit the actual needs of professionals. This paper concerns a research project aimed at developing a multicriteria design-aid tool for the early design stages of urban projects adapting to climate change. The tool partially draws on the methods of practitioners, and their understanding of the city. In the first part of the paper, we will present results from the first phase of the project that undertook a series of consultations with practitioners through a questionnaire with over 200 respondents, and two design workshops centred on adaptation. The consultation showed that evaluation tools were very little used. Moreover, the results suggested that practitioners have solution-based approaches of design. Indeed, during the workshops, potential solutions were used to understand and explore the problem. Finally, through the workshop design process the main sources of knowledge were personal experience and education. Consequently, a design-aid tool should reflect this solution-based design process, but also be an educational tool. The second part of the paper will describe the structure of our tool as a web application. The application will guide the users following three stages of an urban project (diagnostic, program and design) proposing methods, solutions and examples relevant to their specific projects. This tool will be dedicated to urban designers and architects but also to students in those fields.