MCPAgentBench: A Real-world Task Benchmark for Evaluating LLM Agent MCP Tool Use

Zixiang Liu, Wenrui Liu, Elsie Dai, Wenhan Yu, Lei Yu, Tong Yang, Yinjun Han, Hong Gao


Abstract
Large Language Models (LLMs) are increasingly serving as autonomous agents, and their utilization of external tools via the Model Context Protocol (MCP) is considered a future trend. Current MCP evaluation sets suffer from issues such as reliance on external MCP services and a lack of difficulty awareness. To address these limitations, we propose MCPAgentBench, a benchmark based on real-world MCP definitions designed to evaluate the tool-use capabilities of agents. We construct a dataset containing authentic tasks and simulated MCP tools. The evaluation employs a dynamic sandbox environment that presents agents with candidate tool lists containing distractors, thereby testing their tool selection and discrimination abilities. Furthermore, we introduce comprehensive metrics to measure both task completion rates and execution efficiency. Experiments conducted on state-of-the-art LLMs reveal significant performance differences in handling complex, multi-step tool invocations. All code is open-source at https://github.com/Brunestuder/MCPAgentBench.
Anthology ID:
2026.realm-1.51
Volume:
Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Ehsan Kamalloo, Nicolas Gontier, Nikolai Rozanov, Maryam Hashemzadeh, Akhil Arora
Venues:
REALM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
764–773
Language:
URL:
https://aclanthology.org/2026.realm-1.51/
DOI:
Bibkey:
Cite (ACL):
Zixiang Liu, Wenrui Liu, Elsie Dai, Wenhan Yu, Lei Yu, Tong Yang, Yinjun Han, and Hong Gao. 2026. MCPAgentBench: A Real-world Task Benchmark for Evaluating LLM Agent MCP Tool Use. In Proceedings of the Second Workshop for REsearch on Agent Language Models (REALM 2026), pages 764–773, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MCPAgentBench: A Real-world Task Benchmark for Evaluating LLM Agent MCP Tool Use (Liu et al., REALM 2026)
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PDF:
https://aclanthology.org/2026.realm-1.51.pdf