Discovering Reinforcement Learning Interfaces with Large Language Models

Fuente: arXiv
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Main Authors: Jaswal, Akshat Singh, Baghel, Ashish, Chopra, Paras
Format: Preprint
Published: 2026
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author Jaswal, Akshat Singh
Baghel, Ashish
Chopra, Paras
author_facet Jaswal, Akshat Singh
Baghel, Ashish
Chopra, Paras
contents Reinforcement learning systems rely on environment interfaces that specify observations and reward functions, yet constructing these interfaces for new tasks often requires substantial manual effort. While recent work has automated reward design using large language models (LLMs), these approaches assume fixed observations and do not address the broader challenge of synthesizing complete task interfaces. We study RL task interface discovery from raw simulator state, where both observation mappings and reward functions must be generated. We propose LIMEN (Code available at https://github.com/Lossfunk/LIMEN), a LLM guided evolutionary framework that produces candidate interfaces as executable programs and iteratively refines them using policy training feedback. Across novel discrete gridworld tasks and continuous control domains spanning locomotion and manipulation, joint evolution of observations and rewards discovers effective interfaces given only a trajectory-level success metric, while optimizing either component alone fails on at least one domain. These results demonstrate that automatic construction of RL interfaces from raw state can substantially reduce manual engineering and that observation and reward components often benefit from co-design, as single-component optimization fails catastrophically on at least one domain in our evaluation suite.
format Preprint
id arxiv_https___arxiv_org_abs_2605_03408
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Discovering Reinforcement Learning Interfaces with Large Language Models
Jaswal, Akshat Singh
Baghel, Ashish
Chopra, Paras
Machine Learning
Artificial Intelligence
Reinforcement learning systems rely on environment interfaces that specify observations and reward functions, yet constructing these interfaces for new tasks often requires substantial manual effort. While recent work has automated reward design using large language models (LLMs), these approaches assume fixed observations and do not address the broader challenge of synthesizing complete task interfaces. We study RL task interface discovery from raw simulator state, where both observation mappings and reward functions must be generated. We propose LIMEN (Code available at https://github.com/Lossfunk/LIMEN), a LLM guided evolutionary framework that produces candidate interfaces as executable programs and iteratively refines them using policy training feedback. Across novel discrete gridworld tasks and continuous control domains spanning locomotion and manipulation, joint evolution of observations and rewards discovers effective interfaces given only a trajectory-level success metric, while optimizing either component alone fails on at least one domain. These results demonstrate that automatic construction of RL interfaces from raw state can substantially reduce manual engineering and that observation and reward components often benefit from co-design, as single-component optimization fails catastrophically on at least one domain in our evaluation suite.
title Discovering Reinforcement Learning Interfaces with Large Language Models
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2605.03408