TOUCAN: Synthesizing 1.5M Tool-Agentic Data from Real-World MCP Environments

Zhangchen Xu, Adriana Meza Soria, Shawn Tan, Anurag Roy, Ashish Sunil Agrawal, Radha Poovendran, Rameswar Panda


Abstract
Large Language Model (LLM) agents are rapidly emerging as powerful systems for automating tasks across domains. Yet progress in the open-source community is constrained by the lack of high quality permissively licensed tool-agentic training data. Existing datasets are limited in diversity, realism, and complexity, particularly regarding multi-tool and multi-turn interactions. To address this gap, we introduce Toucan, which contains 1.5 million trajectories synthesized from nearly 500 real-world Model Context Protocols (MCPs). Unlike prior work, Toucan leverages authentic MCP environments to generate diverse, realistic, and challenging tasks with trajectories involving real tool execution. Our pipeline first produces a broad spectrum of tool-use queries using five distinct models, applies model-based quality filtering, and then generates agentic trajectories with three teacher models using two agentic frameworks. Rigorous rule-based and model-based validation ensures high-quality outputs. We also introduce three extensions to further diversify tasks and simulate multi-turn conversations. Models fine-tuned on Toucan outperform larger closed-source counterparts on the BFCL V3 benchmark and establish a new Pareto optimum on MCP-Universe Bench.
Anthology ID:
2026.emnlp-main.809
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
18842–18872
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URL:
https://aclanthology.org/2026.emnlp-main.809/
DOI:
Bibkey:
Cite (ACL):
Zhangchen Xu, Adriana Meza Soria, Shawn Tan, Anurag Roy, Ashish Sunil Agrawal, Radha Poovendran, and Rameswar Panda. 2026. TOUCAN: Synthesizing 1.5M Tool-Agentic Data from Real-World MCP Environments. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 18842–18872, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TOUCAN: Synthesizing 1.5M Tool-Agentic Data from Real-World MCP Environments (Xu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.809.pdf