MCPGen: Benchmarking LLMs on Executable MCP Workflow Development

Yingxuan Yang, Jiaqi Liu, Lirui Guan, Jiaye Gao, Weiwen Liu, Weinan Zhang, Ying Wen


Abstract
We study whether LLMs can produce executable workflow artifacts that remain consistent across graph structure, tool implementation, schema bindings, and runtime wiring. In this setting, correctness depends on cross-layer consistency: a workflow may be structurally plausible, yet still fail because tool implementations, schema bindings, or runtime execution do not align. Existing benchmarks largely evaluate these capabilities in isolation or rely on trajectory-level proxies, leaving open whether generated workflow artifacts execute end-to-end. We introduce MCPGen, an executable benchmark for Model Context Protocol (MCP) workflow development. MCPGen contains 100 self-contained MCP projects across 16 application domains and evaluates three diagnostic tasks: workflow reconstruction, tool creation, and backward-compatible workflow extension. We evaluate 11 representative LLMs in a single-turn foundation-model setting, assessing generated artifacts through static analysis, unit and integration tests, and process-isolated end-to-end execution. Models reach 88.5% on workflow reconstruction, but no model exceeds 57% end-to-end execution success. Per-tool unit-test pass rates reach 63.8%, while project-level integration success does not exceed 45%, suggesting that integration remains a major bottleneck even when isolated tool tests pass. Code and data are available at https://github.com/zoe-yyx/MCPGen_Official.
Anthology ID:
2026.findings-emnlp.1358
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
28846–28859
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1358/
DOI:
Bibkey:
Cite (ACL):
Yingxuan Yang, Jiaqi Liu, Lirui Guan, Jiaye Gao, Weiwen Liu, Weinan Zhang, and Ying Wen. 2026. MCPGen: Benchmarking LLMs on Executable MCP Workflow Development. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 28846–28859, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MCPGen: Benchmarking LLMs on Executable MCP Workflow Development (Yang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1358.pdf