Negotiations are underway at the WHO for a legally binding instrument for pandemic prevention, preparedness and response. As seen in the International Health Regulations, however, countries signing up to an agreement is no guarantee of its effective implementation. We, therefore, investigated the potential design features of an accountability framework for the proposed pandemic agreement that could promote countries' compliance with it. We reviewed the governance of a number of international institutions and conducted over 40 interviews with stakeholders and experts to investigate how the pandemic agreement could be governed.We found that enforcement mechanisms are a key feature for promoting the compliance of countries with the obligations they sign up for under international agreements but that they are inconsistently applied. It is difficult to design enforcement mechanisms that successfully avoid inflicting unintended harm and, so, we found that enforcement mechanisms generally rely on soft political levers rather than hard legal ones to promote compliance. Identifying reliable information on states' behaviour with regard to their legal obligations requires using a diverse range of information, including civil society and intergovernmental organisations, and maintaining legal, financial, and political independence.We, therefore, propose that there should be an independent mechanism to monitor states' compliance with and reporting on the pandemic agreement. It would mainly triangulate a diverse range of pre-existing information and have the authority to receive confidential reports and seek further information from states. It would report to a high-level political body to promote compliance with the pandemic agreement.