Giving Robots a Plan: AI Masters Household Tasks with Hierarchical Reasoning

Author: Denis Avetisyan


A new framework empowers embodied agents to break down complex instructions into manageable steps, paving the way for more capable and adaptable robotic assistants.

The architecture operates on the premise that complex tasks are best addressed not through direct programming, but through a layered decomposition-a high-level planner first clarifies ambiguities via environmental feedback, then breaks down instructions into natural language sub-tasks, which a low-level planner subsequently translates into executable action sequences grounded in available skills, effectively growing a solution rather than constructing one.
The architecture operates on the premise that complex tasks are best addressed not through direct programming, but through a layered decomposition-a high-level planner first clarifies ambiguities via environmental feedback, then breaks down instructions into natural language sub-tasks, which a low-level planner subsequently translates into executable action sequences grounded in available skills, effectively growing a solution rather than constructing one.

Researchers introduce HELP, a hierarchical planning system leveraging large language models to enable robust task decomposition and execution directly on robot hardware.

Robust task planning remains a challenge for embodied agents operating in complex environments, despite advances in large language models (LLMs). This paper introduces ‘HELP: Hierarchical Embodied Language Planner for Household Tasks’, a novel framework that decomposes complex goals into manageable sub-tasks using a hierarchy of LLM-based agents. By enabling efficient task execution with relatively small, open-source models directly on the agent’s hardware, HELP demonstrates a path toward truly autonomous embodied AI. Could this approach unlock more accessible and adaptable robotic systems for everyday life?


The Inevitable Complexity of Action

Conventional robotic planning often falters when confronted with tasks demanding a sequence of actions extending into the future. This difficulty arises from what is known as combinatorial explosion – as the number of possible actions and states increases, the computational resources required to explore every viable path grow exponentially. Consider a simple task like making a sandwich; a robot must not only grasp the bread and fillings, but also account for variations in object position, potential collisions, and the order of operations. Each added step dramatically increases the branching possibilities, quickly overwhelming even powerful computers. Consequently, robots struggle with tasks that humans perform effortlessly, highlighting the need for more efficient and adaptable planning strategies capable of navigating complex, long-horizon scenarios without succumbing to this computational bottleneck.

Integrating Large Language Models (LLMs) into robotic systems, while promising, presents notable hurdles. A primary constraint lies in the limited context window of these models; robots operate within a continuous stream of sensory input and require reasoning over extended periods, far exceeding the typical input capacity of current LLMs. Furthermore, LLMs, trained on vast text datasets, are prone to ‘hallucinations’ – generating plausible-sounding but factually incorrect statements – which can translate to unsafe or illogical actions in a physical environment. These models may confidently instruct a robot to perform an impossible task or misinterpret sensor data, necessitating robust mechanisms for grounding LLM outputs in real-world constraints and verifying the feasibility of proposed actions before execution. Overcoming these challenges is crucial for deploying LLMs in safety-critical robotic applications.

Truly intelligent embodied artificial intelligence necessitates a synergistic blend of cognitive and physical capabilities. It is not sufficient for a system to simply plan a sequence of actions; it must also reliably execute those actions in the unpredictable, noisy environment of the real world. This demands more than just scaling up existing Large Language Models, which excel at symbolic reasoning but often struggle with grounding those abstractions in physical reality. Instead, research focuses on architectures that seamlessly integrate high-level reasoning – such as task decomposition, goal setting, and error correction – with robust low-level control systems capable of handling sensorimotor contingencies, physical constraints, and unforeseen disturbances. The ultimate goal is a system that doesn’t just think about what to do, but demonstrably does it, adapting and recovering from errors as a human would, forging a path toward truly versatile and autonomous robots.

A hierarchical LLM system translates natural language instructions into executable robot actions by first decomposing them into subtasks and then generating corresponding pseudocode grounded in the robot’s capabilities.
A hierarchical LLM system translates natural language instructions into executable robot actions by first decomposing them into subtasks and then generating corresponding pseudocode grounded in the robot’s capabilities.

Deconstructing the Task: A Necessary Illusion

The Hierarchical Embodied Language Planner (HELP) addresses complex task completion through decomposition. The High-Level Planner (HLP) functions as the initial processing unit, receiving a complex instruction and systematically breaking it down into a series of discrete, sequentially ordered sub-goals. This decomposition is not merely a division of labor; it establishes a hierarchical structure where each sub-goal represents a necessary step toward the overall task completion. By reducing complexity in this manner, HELP enables the execution of tasks that would be intractable for systems relying on single-step reasoning or direct action selection. The resulting sub-goal sequence serves as a structured plan for the subsequent Low-Level Planner.

The High-Level Planner (HLP) within the Hierarchical Embodied Language Planner (HELP) processes natural language instructions and applies task decomposition to generate a structured plan consisting of sequential sub-goals. This approach moves beyond single-step reasoning by breaking down complex tasks into smaller, more manageable units. The HLP analyzes the input instruction to identify the overall objective and then recursively decomposes it into a hierarchy of sub-goals, defining the necessary steps and their logical order for successful task completion. This structured plan serves as a roadmap for the Low-Level Planner, enabling the execution of multi-step tasks that would be intractable for systems relying on direct instruction-to-action mapping.

The Low-Level Planner (LLP) component receives discrete sub-goals from the High-Level Planner and converts them into a series of executable action sequences. This translation process involves identifying the specific robotic actions required to achieve each sub-goal, considering factors such as joint angles, gripper control, and trajectory planning. The LLP utilizes pre-defined action primitives and potentially learned skills to construct these sequences, ensuring they are feasible for the robot’s physical capabilities and environment. Successful execution of these action sequences directly addresses the decomposed task, effectively linking the initial high-level intention to concrete physical actions.

An embodied agent successfully executed the plan generated from the natural language instruction
An embodied agent successfully executed the plan generated from the natural language instruction “put the toy cube in the white box”, demonstrated by sequential actions including moving to, picking up, and placing the cube as shown in steps a-h.

The Illusion of Control: Validation Through Experiment

The Habitat Learning and Embodied Reasoning Platform (HELP) was validated using the ALFRED dataset, a widely-recognized benchmark for embodied artificial intelligence research. ALFRED presents a series of complex, realistic household tasks requiring agents to navigate and interact with virtual environments to achieve specified goals. Successful performance on ALFRED necessitates capabilities in visual perception, natural language understanding, long-horizon planning, and robust execution in dynamic settings. The dataset’s complexity arises from the combination of diverse environments, intricate task instructions, and the need for agents to generalize to unseen scenarios, making it a stringent test for embodied AI systems.

Real-world robotic experiments demonstrate that the HELP system achieves an 80% success rate in task completion. This metric was determined through physical trials using a robotic platform executing a variety of household tasks. The 80% success rate indicates the system’s ability to reliably translate planned actions into successful execution within a non-simulated environment, and signifies robust performance despite the complexities of real-world sensor data and physical interactions. This performance level was consistently maintained across a dedicated test set of scenarios, validating the system’s generalization capability.

HELP’s task feasibility estimation was assessed using a dedicated test set, resulting in an accuracy of 77%. This metric quantifies the system’s ability to reliably predict whether a given task, described through natural language, can be successfully completed by the agent. The test set comprised a range of scenarios designed to challenge the system’s understanding of task requirements and environmental constraints, providing a robust measure of its predictive capabilities prior to task execution. Accuracy is calculated as the percentage of tasks for which the system’s prediction of feasibility aligned with the actual outcome of attempting the task.

The HELP system attained a Plan Execution Metric (PEM) score of 0.64 on the ALFRED benchmark when utilizing grounding techniques. This score signifies a substantial performance increase compared to existing baseline approaches evaluated on the same dataset. The PEM score assesses the quality of an agent’s planned actions in completing complex, multi-step tasks within a simulated household environment, with higher scores indicating more successful and efficient task completion. Grounding, in this context, refers to the system’s ability to link language instructions to perceptual observations, enabling more accurate plan execution.

Across plans of varying length (2 to 16 steps, with 200 plans per length), HELP and LLP consistently outperform baseline approaches.
Across plans of varying length (2 to 16 steps, with 200 plans per length), HELP and LLP consistently outperform baseline approaches.

The System Adapts: Embracing the Inevitable

The HELP system distinguishes itself through its commitment to open-source Large Language Models (LLMs), a design choice that fundamentally alters accessibility and control within the field of embodied AI. By eschewing dependence on proprietary APIs, the system avoids vendor lock-in and associated costs, while simultaneously enabling researchers and developers to deeply inspect, modify, and extend the underlying language processing capabilities. This open architecture fosters a collaborative environment, allowing for community-driven improvements and the tailoring of the LLM to specific robotic platforms or application domains. The use of open-source LLMs not only democratizes access to advanced AI tools but also promotes transparency and reproducibility, critical elements for building trust and accelerating innovation in robotics and beyond.

The system demonstrates enhanced reliability and flexibility through its capacity to incorporate environmental feedback into ongoing planning. Rather than rigidly adhering to pre-defined sequences, the architecture continuously assesses its surroundings and adjusts its actions based on real-time sensory input. This dynamic refinement is crucial in unpredictable settings, allowing the system to recover from unexpected obstacles or changes in conditions. By iteratively comparing planned actions with perceived outcomes, the system effectively learns from experience, improving its ability to navigate and achieve goals even when faced with unforeseen circumstances. This feedback loop not only enhances robustness – the ability to withstand disturbances – but also promotes adaptability, enabling the system to thrive in ever-changing environments.

The system bridges the gap between language and the physical world through the utilization of Sentence-BERT embeddings, a technique that translates both linguistic instructions and perceptual observations into a shared vector space. This allows the system to assess the similarity between a stated goal – such as “pick up the red block” – and its current sensory input from cameras and other sensors. By representing both language and perception as numerical vectors, the system can determine how well its understanding of the instruction aligns with its surroundings, enabling it to resolve ambiguities and adapt plans based on what it ‘sees’. This grounding in perception is crucial for robust performance in real-world scenarios, as it moves beyond purely symbolic reasoning to incorporate contextual awareness and improve the reliability of task execution.

Dynamically selecting relevant examples based on instruction similarity consistently improves performance across all metrics compared to using fixed examples.
Dynamically selecting relevant examples based on instruction similarity consistently improves performance across all metrics compared to using fixed examples.

The pursuit of embodied AI, as demonstrated by HELP’s hierarchical planning, reveals a fundamental truth: systems aren’t built, they evolve. This framework doesn’t simply instruct an agent; it cultivates a capacity for decomposition, allowing complexity to emerge from iterative refinement. Vinton Cerf observed, “The Internet is not about technology; it’s about people.” Similarly, HELP isn’t about algorithms, but about enabling agents to navigate the unpredictable realities of a household environment. Monitoring, in this context, becomes the art of fearing consciously – anticipating the inevitable deviations from a planned trajectory and designing for graceful recovery. That’s not a bug-it’s a revelation of the system’s inherent adaptability.

The Turning of the Wheel

This work, like all constructions, merely delays the inevitable return to chaos. HELP offers a refined articulation of task decomposition, yet every sub-goal created is a new surface for entropy to cling to. The elegance of hierarchical planning should not be mistaken for control; it is simply a more graceful acceptance of complexity. Every dependency is a promise made to the past, a debt accruing interest with each passing cycle. The true measure of such systems will not be their initial performance, but their capacity for self-repair.

The current focus on scaling models-on building ever-larger towers-feels increasingly…circular. The capacity to run these architectures on the agent’s hardware is a step, certainly, but it addresses a symptom, not the disease. The limitations of natural language understanding will not be solved by more parameters; they will be exposed by the subtle failures in execution, the quiet misunderstandings between intention and action.

The path forward lies not in building more, but in learning to listen to what already exists. Everything built will one day start fixing itself – the challenge is to create systems that invite that self-correction, that embrace the imperfections inherent in every cycle. The goal isn’t to eliminate failure, but to design for its inevitable arrival, to see it not as a bug, but as a necessary iteration.


Original article: https://arxiv.org/pdf/2512.21723.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2025-12-29 19:59