Let Me Do It For You: Towards LLM Empowered Recommendation via Tool Learning (2405.15114v1)

Abstract: Conventional recommender systems (RSs) face challenges in precisely capturing users' fine-grained preferences. LLMs have shown capabilities in commonsense reasoning and leveraging external tools that may help address these challenges. However, existing LLM-based RSs suffer from hallucinations, misalignment between the semantic space of items and the behavior space of users, or overly simplistic control strategies (e.g., whether to rank or directly present existing results). To bridge these gap, we introduce ToolRec, a framework for LLM-empowered recommendations via tool learning that uses LLMs as surrogate users, thereby guiding the recommendation process and invoking external tools to generate a recommendation list that aligns closely with users' nuanced preferences. We formulate the recommendation process as a process aimed at exploring user interests in attribute granularity. The process factors in the nuances of the context and user preferences. The LLM then invokes external tools based on a user's attribute instructions and probes different segments of the item pool. We consider two types of attribute-oriented tools: rank tools and retrieval tools. Through the integration of LLMs, ToolRec enables conventional recommender systems to become external tools with a natural language interface. Extensive experiments verify the effectiveness of ToolRec, particularly in scenarios that are rich in semantic content.

Towards LLM Empowered Recommendation via Tool Learning

The paper "Let Me Do It For You: Towards LLM Empowered Recommendation via Tool Learning" by Yuyue Zhao et al. addresses significant challenges in recommender systems (RSs) by leveraging the capabilities of LLMs. The authors introduce a novel framework, ToolRec, which employs LLMs as surrogate users to enhance the recommendation process by using external tools to address the misalignment between the semantic space of items and the behavior space of users.

Introduction

Recommender systems are designed to infer user preferences and recommend items accordingly. However, conventional RSs face two main limitations:

1. They often inadequately capture the fine-grained preferences of users based solely on historical interaction data.
2. They lack sufficient commonsense knowledge about users and items, restricting the scope of recommendations.

In addressing these limitations, the authors propose ToolRec, a framework that employs LLMs to emulate user decision-making processes and guide the recommendation process using attribute-oriented tools.

Methodology

The core of ToolRec involves three key components:

1. User Decision Simulation.

The LLM initializes with the user's historical behavior data and acts as a surrogate user to evaluate preferences against the current scenario. Employing a chain-of-thought (CoT) prompting methodology, the LLM's decisions guide the recommendation journey by invoking external tools to refine the item recommendations based on specific attributes.

2. Attribute-oriented Tools.

ToolRec includes two types of attribute-oriented tools: rank tools and retrieval tools. The rank tools use ranking instructions tailored to specific attributes, while retrieval tools utilize an additional attribute encoder to explore different segments of the item pool effectively. The learning setup for these tools includes a pre-training stage where a user's historical behavior sequence is encoded, followed by a fine-tuning stage where additional attribute-specific encoders are trained.

3. Memory Strategy.

The memory strategy ensures the correctness of retrieving items and systematically orders candidate items by associating them with their respective tool annotations. This mechanism assists the LLM in refining the final recommendation list to align with user preferences accurately.

Experimental Evaluation

The authors conducted extensive experiments on three real-world datasets: ML-1M, Amazon-Book, and Yelp2018. The evaluation metrics used were NDCG@10 and Recall@10.

The results demonstrated that ToolRec outperforms conventional RSs and various LLM-based RSs in domains rich in semantic content. Highlights include:

• ToolRec's superior performance on the ML-1M and Amazon-Book datasets, attributed to its effective alignment with user interests through iterative refinements.
• Contributions of the user decision simulation, memory strategy, and attribute-oriented tools in enhancing the quality of recommendations.
• The potential of LLMs to incorporate broader attribute knowledge, moving beyond the narrow focus of conventional RSs.

Implications and Future Directions

The implications of ToolRec are significant for both practical applications and theoretical advancements in AI:

1. Practical Applications. By integrating LLMs with conventional RSs, ToolRec provides a robust method for achieving personalized recommendations without the need for extensive fine-tuning of LLMs.
2. Theoretical Advances. The paper highlights the potential benefits of LLMs in capturing commonsense reasoning and user preferences, suggesting further exploration into domain-specific fine-tuning and the integration of diverse external tools.

Future research directions may include:

• Incorporating recommendation-specific knowledge into LLMs to enhance the tool learning process.
• Exploring the use of diverse external tools, such as search engines and databases, to achieve more comprehensive recommendations.
• Developing self-reflection strategies within LLMs to iteratively improve recommendation quality.

Conclusion

The paper makes significant strides towards enhancing RSs by leveraging LLMs' capabilities for tool learning. ToolRec's framework demonstrates how LLMs can act as surrogate users to emulate human-like decision-making, thus addressing the limitations of conventional RSs. While the approach shows considerable promise, particularly in domains rich with semantic content, further research is needed to refine and expand upon these initial findings. The integration of LLMs into recommendation tasks represents an exciting frontier in AI, promising more personalized and accurate recommendations in the future.