A2A Research Digest — 2026/03/11: A Survey of Agent Interoperability Protocols
This digest covers recent academic research on the Agent-to-Agent (A2A) protocol and related interoperability standards.
Paper 1: A Survey of Agent Interoperability Protocols
Authors: Abul Ehtesham, Aditi Singh, Gaurav Kumar Gupta, Saket Kumar
arXiv: 2505.02279
Date: May 4, 2025 (v1), May 23, 2025 (v2)
Core Contributions:
- Comprehensive survey of four emerging agent communication protocols: MCP, ACP, A2A, and ANP
- Systematic comparison across interaction modes, discovery mechanisms, and security models
- Phased adoption roadmap for LLM-powered agent ecosystems
Technical Summary:
The paper examines how autonomous agents built on large language models require standardized protocols to integrate tools, share context, and coordinate tasks across heterogeneous systems. The four protocols analyzed are:
- MCP (Model Context Protocol): JSON-RPC client-server interface for secure tool invocation and typed data exchange
- ACP (Agent Communication Protocol): RESTful HTTP-based protocol supporting MIME-typed multipart messages with session management
- A2A (Agent-to-Agent Protocol): Peer-to-peer task delegation using capability-based Agent Cards
- ANP (Agent Network Protocol): Open network agent discovery using W3C DIDs and JSON-LD graphs
Phased Adoption Roadmap:
- Begin with MCP for tool access
- Add ACP for structured, multimodal messaging
- Implement A2A for collaborative task execution
- Extend to ANP for decentralized agent marketplaces
Paper 2: Building A Secure Agentic AI Application Leveraging A2A Protocol
Authors: Idan Habler, Ken Huang, Vineeth Sai Narajala, Prashant Kulkarni
arXiv: 2504.16902
Date: April 23, 2025 (v1), May 2, 2025 (v2)
Core Contributions:
- Comprehensive security analysis of the A2A protocol
- Threat modeling using the MAESTRO framework
- Practical secure development methodologies and architectural best practices
Technical Summary:
As Agentic AI systems evolve from basic workflows to complex multi-agent collaboration, the A2A protocol becomes essential. This paper provides a security-focused analysis examining:
- Agent Card Management: Security considerations for capability discovery
- Task Execution Integrity: Ensuring reliable task delegation
- Authentication Methodologies: Secure client-server interactions
- A2A + MCP Synergy: How the two protocols complement each other for secure interoperability
The MAESTRO framework (designed for AI risks) is applied to proactively identify potential security issues in A2A deployments.
Paper 3: A Study on the MCP x A2A Framework
Authors: Cheonsu Jeong
arXiv: 2506.01804
Date: June 2, 2025 (v1), June 9, 2025 (v2)
Published: Journal of Intelligence and Information Systems, 31(3), 141-170 (2025)
Core Contributions:
- In-depth technical analysis of Google's A2A and Anthropic's MCP
- Implementation methodology for MCP x A2A integration
- Exploration of how two protocols complement each other
Technical Summary:
This study takes an integrated approach, exploring how A2A and MCP can complement each other to address interoperability issues:
- A2A Role: Standardized communication for agents to collaborate across heterogeneous environments
- MCP Role: Structured I/O framework for agents to connect with external tools and resources
- Integration Benefits: Combined protocol approach enables more robust agent ecosystems
Analysis & Insights
Key Trends:
Protocol Convergence: The research community increasingly recognizes that MCP and A2A are complementary, not competing. MCP handles agent-to-tool communication while A2A handles agent-to-agent collaboration.
Security Focus: With multi-agent systems becoming more prevalent, security analysis (as in Habler & Huang 2025) is crucial for enterprise adoption.
Standardization Push: The Linux Foundation's stewardship of A2A (as of June 2025) signals industry-wide commitment to open standards.
Practical Implementation: Papers like Jeong (2025) provide actionable implementation guidance for combining MCP and A2A in real-world applications.
Implications for Practitioners:
- Start with MCP for tool integration
- Add A2A for multi-agent collaboration
- Consider ANP for future decentralized agent marketplaces
- Prioritize security from the design phase
References
- Ehtesham, A., et al. (2025). A survey of agent interoperability protocols. arXiv:2505.02279
- Habler, I., et al. (2025). Building A Secure Agentic AI Application Leveraging A2A Protocol. arXiv:2504.16902
- Jeong, C. (2025). A Study on the MCP x A2A Framework. arXiv:2506.01804
This digest is part of the A2A Research series, tracking academic developments in agent interoperability protocols.
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