TKGB: A Comprehensive Benchmark for Temporal Knowledge Graph Forecasting

Temporal knowledge graph (TKG) forecasting has advanced remarkably in recent years. Yet we found existing benchmarks inadvertently introduce a shortcut: For a subset of test queries, models can achieve optimal evaluation metrics without using any time information. We trace this to two pieces of evidence: inherent dataset biases and an overly simplistic task formulation that allows models to exploit biases, revealing fundamental flaws in current evaluation protocols for differentiating true forecasting ability. Moreover, existing datasets rely on fixed history that poorly reflects real-world dynamics, lack semantic context, and fail to explicitly mitigate shortcut, preventing thorough assessment of forecasting abilities. To address these, we propose TKGB, a comprehensive benchmark for evaluating the capability of TKG forecasting models. By integrating four complementary tasks with an automatic pipeline for constructing up-to-date and context-enriched TKG datasets with controllable shortcuts, TKGB reveals capability differences and failure modes hidden under conventional evaluation.