🤖 AI Summary
Existing tool-use benchmarks report only aggregate success rates, lacking fine-grained diagnostic insights into LLMs’ failure modes during tool invocation.
Method: We introduce the first reproducible, attributable diagnostic benchmark for tool use. It systematically defines and empirically validates seven interpretable error categories—including malformed parameter formatting, incorrect tool selection, and context forgetting—grounded in multi-source real-world tool interaction scenarios. Our test suite integrates human annotation with pattern-driven analysis to enable automated error-type identification and statistical attribution.
Contribution/Results: Experiments reveal that all seven error types occur pervasively across mainstream LLMs. The benchmark is publicly released, enabling precise error root-cause analysis and facilitating targeted model improvement. It significantly advances the interpretability, debuggability, and robustness of LLM-based tool-use systems.
📝 Abstract
Evaluating the output of Large Language Models (LLMs) is one of the most critical aspects of building a performant compound AI system. Since the output from LLMs propagate to downstream steps, identifying LLM errors is crucial to system performance. A common task for LLMs in AI systems is tool use. While there are several benchmark environments for evaluating LLMs on this task, they typically only give a success rate without any explanation of the failure cases. To solve this problem, we introduce SpecTool, a new benchmark to identify error patterns in LLM output on tool-use tasks. Our benchmark data set comprises of queries from diverse environments that can be used to test for the presence of seven newly characterized error patterns. Using SPECTOOL , we show that even the most prominent LLMs exhibit these error patterns in their outputs. Researchers can use the analysis and insights from SPECTOOL to guide their error mitigation strategies.