The prioritization of energy policies by local governments represents a process of competitive attention allocation among various policy tools, and its outcomes significantly influence the ultimate effectiveness of the low-carbon transformation of energy. Building on the theoretical framework of governmental attention allocation, the research first analyzes how internal–external governmental relations shape policy tool prioritization through comparative case studies, followed by a discrete choice experiment (DCE) to empirically examine local governments’ preferences for policy tool attributes under different relational conditions. The findings reveal that county governments (CGs) dominated by intergovernmental relationships tend to align their priorities with the governance requirements of higher-level authorities and emphasize clarity, operability, economic attributes, and political considerations in policy tool selection. In contrast, governments dominated by government–enterprise relationships place greater emphasis on the impact of policy tools on enterprise production and focus primarily on economic attributes and operability. The study demonstrates that under different internal–external government relations, CGs prioritize distinct attributes of policy tools, which leads to varied rankings of energy policy tools. Building effective incentive and constraint mechanisms on the basis of rationalizing vertical intergovernmental and government–enterprise relationships, while optimizing energy policy supply to guide local governments in selecting context-appropriate energy policy tools, serves as a crucial approach to advancing urban low-carbon energy transitions and achieving sustainable socioeconomic development.