@inproceedings{rakhsha-etal-2026-lumina,
    title = "{LUMINA}: Long-horizon Understanding for Multi-turn Interactive Agents",
    author = "Rakhsha, Amin  and
      Hehn, Thomas  and
      Mazzaglia, Pietro  and
      Massoli, Fabio Valerio  and
      Behboodi, Arash  and
      Orekondy, Tribhuvanesh",
    editor = "Liakata, Maria  and
      Moreira, Viviane P.  and
      Zhang, Jiajun  and
      Jurgens, David",
    booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {ACL} 2026",
    month = jul,
    year = "2026",
    address = "San Diego, California, United States",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/ingest-acl/2026.findings-acl.190/",
    pages = "3913--3926",
    ISBN = "979-8-89176-395-1",
    abstract = "Large language models can perform well on many isolated tasks, yet they continue to struggle on multi-turn, long-horizon agentic problems that require skills such as planning, state tracking, and long context processing. In this work, we aim to better understand the relative importance of advancing these underlying capabilities for success on such tasks. We develop an oracle counterfactual framework for multi-turn problems that asks: how would an agent perform if it could leverage an oracle to perfectly execute a specific skill? The change in the agent{'}s performance due to this oracle assistance allows us to measure the criticality of that skill in the future advancement of AI agents. We introduce a suite of procedurally generated, game-like tasks with tunable complexity. These controlled environments allow us to provide precise oracle interventions, such as perfect planning or flawless state tracking, and make it possible to isolate the contribution of each oracle without confounding effects present in real-world benchmarks. Our results show that while some interventions (e.g., planning) consistently improve performance across settings, the usefulness of other skills is dependent on the properties of the environment and language model. Our work sheds light on the challenges of multi-turn agentic environments to guide the future efforts in the development of AI agents and language models."
}