REFLEX with Jev for Efficient Selective Control in LLM Agents
Tiantong Wu, Wei Yang Bryan Lim
- Published
- Sep 22, 2026 — 14:54 UTC
Problem
This work addresses the gap in efficiency of decision-making in large language model (LLM) agents that utilize generative models. The authors highlight the need for improved mechanisms that can reduce reliance on strong models while maintaining high performance. This paper is a preprint and has not undergone peer review.
Method
The authors propose the REFLEX agent architecture, which incorporates a fast, typed decision layer called Jev. This decision layer is designed to optimize the selection process for actions based on the agent's confidence. When the agent's confidence is low or when generation is required, a fallback mechanism is employed that calls upon a strong LLM. The performance of the REFLEX architecture is evaluated using a frozen 100-task benchmark, with a primary performance metric being the success rate of the agent's decisions. The evaluation methods include external BFCL and $τ$-style evaluations, which assess the agent's decision-making capabilities in various scenarios.
Results
The REFLEX architecture achieves a success rate of 95% when compared to a strong-only agent. Additionally, it demonstrates a significant reduction in the number of calls to the strong model, with a 72.7% decrease in calls compared to the strong-only agent. These results indicate that the REFLEX architecture can maintain high performance while reducing computational overhead associated with strong model calls.
Limitations
The authors note that the reliability of the REFLEX architecture is contingent upon the size of the action set and the presence of near-valid alternatives near authorization boundaries. Furthermore, they acknowledge that the advantages of their approach may be limited when compared to a cheap generative cascade, particularly in scenarios where ordinary routing is highly accurate. These factors could impact the overall effectiveness of the REFLEX architecture in certain applications.
Why it matters
The implications of this work are significant for downstream applications of LLM agents, particularly in environments where computational efficiency is critical. By reducing the dependency on strong models while maintaining high success rates, the REFLEX architecture could enable more scalable and efficient deployment of LLM agents in real-world applications. This approach may pave the way for further research into hybrid decision-making frameworks that balance performance and resource utilization.
By Callan Zhang · Sep 22, 2026 · Editorial standards →
Summarised from the primary source with AI assistance under human editorial oversight. Turing Wire is not a primary source — read the original for the authoritative account.
Source: arXiv cs.AI
