Preprint
Large Language Models

Reaching Agreement Among LLM Agents

Chaoyi Ruan, Yiliang Wang, Ziji Shi, Jialin Li
December 23, 2025arXiv.org2 citations

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arXiv.org

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2025

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Abstract

Multi-agent systems have extended the capability of agentic AI. Instead of single inference passes, multiple agents perform collective reasoning to derive high quality answers. However, existing multi-agent orchestration relies on static heuristic workflows such as fixed loop limits and barrier synchronization. These ad-hoc approaches waste computational resources, incur high latency due to stragglers, and risk finalizing transient agreements. We argue that reliable multi-agent reasoning requires a formal foundation analogous to classical distributed consensus problem. To that end, we propose a formal model of the multi-agent refinement problem. The model includes definitions of the correctness guarantees and formal semantics of agent reasoning. We then introduce Aegean, a consensus protocol designed for stochastic reasoning agents that solves multi-agent refinement. We implement the protocol in Aegean-Serve, a consensus-aware serving engine that performs incremental quorum detection across concurrent agent executions, enabling early termination when sufficient agents converge. Evaluation using four mathematical reasoning benchmarks shows that Aegean provides provable safety and liveness guarantees while reducing latency by 1.2--20$\times$ compared to state-of-the-art baselines, maintaining answer quality within 2.5%. Consistent gains across both local GPU deployments and commercial API providers validate that consensus-based orchestration eliminates straggler delays without sacrificing correctness.

Analysis

Why This Paper Matters

Current multi-agent LLM systems rely on static heuristics like fixed loop limits and barrier synchronization, which waste compute and suffer from straggler delays. This paper identifies a fundamental gap: the lack of a formal foundation for multi-agent reasoning analogous to classical distributed consensus. By framing the problem as a consensus challenge, the authors open the door to principled solutions with provable guarantees.

The practical impact is significant. As agentic AI moves toward production, latency and resource efficiency become critical. Aegean's ability to terminate early once sufficient agreement is reached directly addresses the straggler problem that plagues synchronous multi-agent workflows. The 1.2–20× latency improvement without sacrificing answer quality makes this approach immediately attractive for deployment.

Technical Contributions

  • Formal model: Defines the multi-agent refinement problem with correctness guarantees (safety, liveness) and formal semantics for stochastic reasoning agents, providing a rigorous foundation.
  • Aegean protocol: A consensus protocol designed for stochastic agents that solves multi-agent refinement with provable safety and liveness, eliminating ad-hoc heuristics.
  • Aegean-Serve: A consensus-aware serving engine that performs incremental quorum detection across concurrent agent executions, enabling early termination when sufficient agents converge.
  • Empirical validation: Tested on four mathematical reasoning benchmarks (likely GSM8K, MATH, etc.) with consistent latency reductions of 1.2–20× and quality degradation under 2.5%.

Results

Aegean achieves 1.2–20× latency reduction compared to state-of-the-art baselines across four mathematical reasoning benchmarks. Answer quality remains within 2.5% of baselines. The gains are consistent across both local GPU deployments and commercial API providers, demonstrating robustness to different execution environments. The protocol eliminates straggler delays without sacrificing correctness, as proven by the formal safety and liveness guarantees.

Significance

This work bridges distributed systems theory and agentic AI, providing a principled alternative to ad-hoc multi-agent orchestration. The formal model and consensus protocol could generalize beyond mathematical reasoning to other domains requiring reliable multi-agent coordination. For practitioners, Aegean-Serve offers a drop-in solution that reduces latency and compute costs while maintaining quality. The paper sets a new standard for evaluating multi-agent systems, moving from heuristic benchmarks to formal correctness guarantees.