Learning from Failures: Heterogeneous Graph Memory for Small Language Model Tool-Using Agents

2026-09-23

AI Summary

针对中小型语言模型在工具使用中出现的结构错误问题，提出FRESH框架，通过经验结构化异构图来提升决策的安全性和可靠性。

Abstract

Small and medium-sized language models offer cost-effective executors for tool-using agents, making them attractive for local and large-scale deployment. However, in long-horizon and stateful environments, they often make structural errors such as missing required observations, performing premature writes, repeating failed calls, and violating action preconditions. These errors can lead to incorrect state updates, policy violations, and costly or irreversible consequences, making reliable tool execution a critical deployment challenge. Existing fine-tuning approaches require substantial data and computation, while flat memory may retrieve failed actions without preserving their causal context or safety conditions. In this paper, we propose FRESH, a Failure-aware Retrieval framework over Experience-Structured Heterogeneous graphs, which transforms historical successes and failures into structured external experience for tool-using agents. By explicitly modeling the dependencies among tasks, actions, errors, repairs, and execution conditions, FRESH helps frozen language models reuse reliable strategies, avoid recurring failures, and make safer decisions in stateful tool interactions. Experiments on $τ$-Bench and AppWorld with multiple open-source models show that FRESH consistently improves task success and tool-use reliability over no-memory agents and representative memory-based baselines.

Problem

• structural errors
• stateful environments
• tool-using agents
• reliable execution
• deployment challenge

Innovation

• Failure-aware Retrieval
• Experience-Structured Heterogeneous Graphs
• Tool-Using Agents
• Reliable Strategies
• Safer Decisions