Applied Research Project "Undoing development: sketching the impacts of cuts in international cooperation" examines how the sharp contraction in official development assistance (ODA) is reshaping the international cooperation system, moving from the distribution of cuts to their cumulative implications for human development, coping capacity, and the broader development paradigm. Drawing on quantitative analysis of international data, an extensive review of academic, policy, and grey literature, 20 semi-structured interviews, a global health sector study, and contrasting country cases in Tanzania and Afghanistan, the report finds that the current contraction is disproportionately affecting least developed countries, Sub-Saharan Africa, and sectors such as health, education, and humanitarian assistance, while exposing the high concentration and limited resilience of existing financing structures. It further finds that commonly cited alternatives, including domestic resource mobilisation, private finance, philanthropy, and emerging donors, cannot currently compensate for ODA losses at the necessary scale, speed or across the affected sectors. Rather than representing a temporary fiscal adjustment, the evidence points to a broader transformation of development cooperation, characterised by greater selectivity, geopolitical prioritisation, more transactional donor motivations, and changing North–South relations. The report concludes that the consequences of these shifts extend beyond reduced financial flows: they risk eroding institutional capacity, service continuity, development gains, and the predictability and legitimacy on which long-term international cooperation depends.