NITI: Neural Plan Concretization for Incremental Execution, Bridging and Trigger Inference from Underspecified Human Policies

Ayan Banerjee, Shomrik Barua Banerjee, Sandeep Gupta


Abstract
Human decision-making in safety-critical domains is governed by abstract policies that intentionally omit exhaustive preconditions/ triggers and contingencies. Executing such underspecified policies reliably in open-world settings remains a fundamental challenge for large language models (LLMs). We introduce NITI, Neural Bridging for Incremental Execution and Trigger Inference from Underspecified Human Policies, a neuro-symbolic framework that treats LLMs not as autonomous planners, but as execution-time concretizers of human intent. NITI incrementally executes abstract policies via verifier-grounded interfaces, infers implicit applicability conditions, repairs execution through neural bridging when assumptions fail, and halts safely under state inconsistency. We evaluate NITI on two structurally distinct embodied domains: a new benchmark of World Cubing Championship 2×2 Rubik’s Cube scrambles (n=50) and a safety-critical automated insulin dosing task. Across multiple frontier LLMs, NITI enables reliable long-horizon execution without task-specific training or search with minimal contextualization infence overhead, substantially outperforming one-shot and chain-of-thought baselines. Our results show that compositional, verifier-grounded execution is essential for safe human–AI collaboration in open-world decision-making. Code and benchmark available here - https://github.com/ImpactLabASU/ACLNITI
Anthology ID:
2026.findings-acl.2007
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
40371–40384
Language:
URL:
https://aclanthology.org/2026.findings-acl.2007/
DOI:
10.18653/v1/2026.findings-acl.2007
Bibkey:
Cite (ACL):
Ayan Banerjee, Shomrik Barua Banerjee, and Sandeep Gupta. 2026. NITI: Neural Plan Concretization for Incremental Execution, Bridging and Trigger Inference from Underspecified Human Policies. In Findings of the Association for Computational Linguistics: ACL 2026, pages 40371–40384, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
NITI: Neural Plan Concretization for Incremental Execution, Bridging and Trigger Inference from Underspecified Human Policies (Banerjee et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-acl.2007.pdf
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