TempTool-R1: Tool-Augmented Reinforcement Learning for Temporal Knowledge Graph Question Answering

Temporal knowledge graph question answering (TKGQA) addresses time-sensitive queries over temporal knowledge graphs, but existing approaches struggle with multi-hop reasoning and implicit temporal constraints. We introduce TempTool-R1, a novel tool-integrated reasoning framework that enables large language models to explicitly use temporal tools for precise reasoning. First, we design a unified temporal tool-based API capable of transforming implicit temporal cues into executable operations, establishing the structural foundation for tool interaction. In the second stage, supervised fine-tuning teaches the model to interweave chain-of-thought reasoning with think-then-tool usage, allowing it to call temporal tools during inference. Finally, we apply reinforcement learning with fine-grained, order-sensitive reward functions tailored for temporal tool use, further refining the model's tool-use policy. Experiments on three challenging TKGQA benchmarks demonstrate that TempTool-R1 significantly outperforms existing methods. In particular, our approach excels on complex questions requiring multi-hop temporal reasoning, highlighting the effectiveness of temporal tool integration and reward optimization in improving TKGQA performance.