The concept of CAT seeks to lower the complexity of international transfers of mitigation outcomes. Consequently, a CAT agreement would not require monitoring and evaluation of the impact of specific actions (projects, policies or programmes) beyond what is required under the Paris Agreement. An ambitious national baseline, strongly modelled with the participation of a diversity of stakeholders, is more credible than claims of mitigation by projects or policies. While it is extremely difficult to evaluate the actual impacts of projects and policies in isolation, it is easier to see the actual movements in emissions through the national inventory. At the same time, it will be necessary to maintain a high level of trust between the members of the CAT and credibility in the eyes of the wider global community. To fulfil these requirements, and in line with reporting requirements under Article 6 and Article 13 of the Paris Agreement, Parties must provide qualitative and quantitative information of their collaborative approaches. This entails information about how participating parties ensure environmental integrity, including that the mitigation outcomes are real, additional and verified, baselines are set conservatively under business as usual, robust MRV is applied, non-permanence and leakage are taken into account. In addition, Parties must ensure avoidance of double counting. The CAT agreement may also require reporting on implementation and sustainability impacts of mitigation actions.