# The Role of Multi-Agent Systems in Realizing Asset Administration Shell Type 3
## 1 Introduction  
Modern factories are becoming increasingly complex and demanding intelligent, connected solutions to support flexible and adaptive operations. However, this evolution introduces significant challenges related to the integration and interoperability of industrial assets. These assets, encompassing a wide range of physical and logical components such as machines, sensors, software, and products, often originate from different vendors and exhibit considerable variation in their communication and functional capabilities. This heterogeneity complicates seamless integration and effective collaboration within increasingly complex industrial ecosystems. To overcome these challenges, the Asset Administration Shell (AAS) [1, 2] has emerged as a fundamental concept in I4.0, providing a standardized digital representation of assets. The AAS encapsulates all relevant information about an asset throughout its entire lifecycle, enabling consistent identification, access, and management through standardized I4.0-compliant interfaces. By providing a standardized approach for asset description and interaction, the AAS acts as a cornerstone for interoperability, facilitating the integration, communication, and data exchange among heterogeneous devices, machines, and systems in industrial environments. Since the introduction of AAS in 2015 [1], the past decade has seen considerable progress in developing traditional AAS solutions, namely AAS Type 1 (passive) and Type 2 (reactive) [3]. While these types offer considerable advantages in standardizing asset representation and enabling interoperability, they lack the active behaviors required to support fully autonomous interactions and intelligent decision-making demanded by dynamic I4.0 environments. In this context, AAS Type 3 (proactive) [3] is a distinct category that extends traditional AAS functionalities by incorporating higher levels of autonomy, intelligence, and collaborative capabilities. These features enable AAS Type 3 to autonomously respond to changing production conditions, negotiate with other assets, and optimize operations in real-time, addressing the flexibility, robustness, and reconfigurability demanded by modern industrial systems. Nevertheless, AAS Type 3 remains an underexplored topic in the literature, lacking formal specifications and comprehensive implementation guidelines. The lack of a detailed specification for AAS Type 3 introduces uncertainty about its structure and implementation. A key question is whether AAS Type 3 requires a uniform, uniquely defined architecture, which may necessitate custom software solutions for its development and deployment, or if it allows for more flexible interpretations. For instance, the literature has increasingly recognized Multi-Agent Systems (MAS) [4] as a promising and suitable approach to support the implementation of AAS Type 3, given their conceptual alignment and inherent support for autonomy, intelligence, and collaborative capabilities [5; 6; 7]. Additionally, MAS have been developed and applied for decades in various domains, demonstrating their benefits and effectiveness in enabling decentralized control, adaptive behavior, and dynamic coordination among distributed entities [8; 9], which are key requirements for realizing AAS Type 3 solutions. Given the incipient nature of AAS Type 3, the lack of formal specifications, and the emerging trend of leveraging MAS to support its implementation, this paper explores the role of MAS in realizing AAS Type 3 through a comprehensive analysis of existing agent-based AAS approaches in the literature. Based on the insights gained from this analysis, this paper proposes an agent-based reference model for AAS Type 3 that offers a modular and standardized foundation to support the development of such solutions. This model consolidates and formalizes recurring architectural patterns and design guidelines identified, contributing to the discussion on the formalization of specifications and providing greater clarity on this emerging topic.