ReserveGate: Reserve-Aware Evidence Scheduling for Long-Horizon Language Agents

Shuang Cao, Rui Li, Louise Ruihua Liu, Alexandre Duprey


Abstract
Long-horizon language agents must decide not only which evidence to use, but also when to pay for it. Retrieval and verification can improve a local decision while exhausting token and tool-time budgets needed later in the episode. We introduce ReserveGate, a one-step evidence controller that combines an explicit uncertainty sketch, an off-policy action-value model, and component-wise feasibility masks over the remaining resources. Unlike a fixed reserve heuristic, ReserveGate adapts its cost penalty when spending runs ahead of episode progress and gradually releases a protected late-stage reserve. Across three benchmark-derived agent environments, ReserveGate improves tight-budget success over the strongest matched controller by 2.6–3.8 percentage points, with gains of 4.6–6.2 points on the longest episode quartile. A latency-constrained variant reduces service-level incidents to 1.2–1.7% across environments while losing at most 0.8 points in success. On LoCoMo-Episodic, cross-model, cross-retriever, rate-limiter, and task-agnostic-sketch comparisons show that the effect is not explained by a single backbone, retrieval stack, or tuned spending rule.
Anthology ID:
2026.findings-emnlp.50
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:
998–1017
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.50/
DOI:
Bibkey:
Cite (ACL):
Shuang Cao, Rui Li, Louise Ruihua Liu, and Alexandre Duprey. 2026. ReserveGate: Reserve-Aware Evidence Scheduling for Long-Horizon Language Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 998–1017, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ReserveGate: Reserve-Aware Evidence Scheduling for Long-Horizon Language Agents (Cao et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.50.pdf