MCP vs Agent2Agent - Use the most intuitive diagrams + the simplest conceptual explanations to understand these two important intelligent agent protocols

Written by
Caleb Hayes
Updated on:June-30th-2025
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In-depth analysis of the intelligent agent protocols MCP and A2A to promote the development of AI technology.

Core content:
1. MCP protocol: a bridge connecting AI assistants with external data sources
2. Advantages and cases of MCP in practical applications
3. A2A protocol: realizing collaboration and communication between different AI systems

Yang Fangxian
Founder of 53AI/Most Valuable Expert of Tencent Cloud (TVP)

MCP (Model Context Protocol): Make AI your “super brain”

MCP is an open standard developed by Anthropic, and its full name is "Model Context Protocol". Its main purpose is to connect AI assistants with external data sources (such as content repositories, business tools, and development environments) to help AI models generate higher quality and more relevant responses. MCP replaces the previous decentralized integration methods by providing a common, open interface standard, enabling AI systems to seamlessly access and utilize external data, thereby improving their capabilities and practicality.

Have you ever thought that when you chat with an AI, it can not only understand what you say, but also instantly browse your company's internal documents, check your emails, and even make suggestions based on your schedule? This is the charm of MCP. It is like installing a pair of "perspective eyes" for AI, allowing it to connect to data and tools in the outside world in real time.

For example, suppose you are the boss of a company and ask AI: "Where is our sales report from last month?" With MCP, AI will not just say "Please provide more information", but will go directly into the company server to find the report, and even analyze the data and tell you: "The report is in the shared folder, and sales increased by 15% over the previous month." This capability relies on MCP to open up the channel between AI and external resources.

Simply put, MCP transforms AI from a "robot" that can only chat to an efficient assistant that can actively obtain information and solve problems. It works by integrating various data sources (such as databases, file systems) and even tools (such as calendars and email clients) through standardized interfaces, making AI's answers more targeted and practical.

A2A (Agent2Agent): AI’s secret recipe for teamwork

A2A is an open protocol launched by Google, and its full name is "Agent2Agent". It aims to enable the connection and collaboration between AI Agents in different ecosystems. The core goal of A2A is to solve  the challenge that Agents in different vendor ecosystems cannot communicate with each other, making it easier for enterprises to adopt Agent  technology. The A2A protocol supports Agents to publish their functions and negotiate how to interact with users or other Agents (for example, through text, forms, or two-way audio/video), thereby achieving safe and efficient collaboration.

If MCP makes AI smarter, then A2A makes AI learn to "work in groups". Imagine that you want to organize a cross-departmental meeting: one AI is responsible for checking your schedule, another AI is responsible for booking a meeting room, and another AI is responsible for notifying the participants. If they work independently, there may be problems such as time conflicts and missed notifications. But with A2A, these AIs are like a group of tacit colleagues who can communicate and coordinate with each other to ensure that everything goes smoothly.

For example, in a smart home, you say, "I want to watch a movie tonight." The voice assistant uses A2A to tell the lighting agent to dim the lights, the audio  agent to play background music, and the TV  agent to turn on the movie channel. The whole process is done in one go, and you don't even feel that there are multiple AIs working behind the scenes. This seamless collaboration is the core value of A2A.

A2A works by defining a "common language" for different AI agents so that they can understand each other's needs and capabilities. For example, one  agent says, "I need a meeting room at 10 a.m. tomorrow." Another  agent responds, "No problem, I've reserved room 301." This conversational collaboration allows AI systems to evolve from working alone to working as a team.

MCP and A2A: What’s the difference?

Although both MCP and A2A are improving AI capabilities, they are like two sides of the same coin, each with its own focus:

MCP  - is the "knowledge engine" of AI. It focuses on making individual AIs more knowledgeable and capable, solving specific problems by connecting to external resources.
A2A  - is a "social network" for AI. It allows multiple AI  Agents to form a team and complete more complex tasks through communication and collaboration. 

To give an example, MCP is like a librarian who can help you find any book; A2A is like a project manager who can coordinate a group of people to organize the books, write book reviews, and even hold a reading club.

What can they do? Let's see the real scene

The magic of MCP

1. Corporate Office
You ask AI in a meeting: "How is the progress of our latest project?" It immediately retrieves the data from the project management software and tells you: "There are 3 tasks left, and they are expected to be completed next week."
2. Customer Support
The customer asked, “When will my order arrive?” The AI ​​customer service queried the logistics system through MCP and replied, “It will be delivered at 10 a.m. tomorrow.”
3. Personal life
You say to AI: "Help me plan a weekend trip." It connects to your email, calendar, and even weather forecast to plan a perfect route.

A2A Stage

1. Recruitment Process
One AI screens resumes, another arranges interviews, and another runs background checks. They update each other on progress through A2A, and the whole process is as smooth as an assembly line.
2. Smart Factory
One AI agent on the production line  monitors the status of equipment, another manages inventory, and the last optimizes logistics. A2A allows them to work together to reduce waste. 
3. Home Assistant
You say "prepare dinner", the kitchen AI turns on the oven, the refrigerator AI checks the ingredients, and the voice assistant reminds you to buy milk - all thanks to A2A's "teamwork".

How do they cooperate?

MCP: The “Master Key” that Connects Everything

The core of MCP is a standardized interface design. You can think of it as a universal plug. Whether it is a company's private database or the calendar on your phone, as long as it is connected to MCP, AI can easily access it. It is not just as simple as "getting data", but also can understand your needs based on the context and provide more considerate answers.

A2A: AI’s “Group Chat Mode”

A2A builds a "chat room"  for AI  Agents. Each Agent can publish its own status and needs, and other  Agents can understand it at a glance. For example, one  Agent says, "I'm too busy, who can take over?" Another Agent immediately responds, "I'll do it!" This dynamic negotiation makes the Multi-Agents system both flexible and efficient.

The future: smarter, more united AI

MCP and A2A are the two pillars of AI evolution. MCP allows AI to continuously expand its intelligence, from only being able to chat to being able to handle complex problems in the real world; A2A allows AI's collaborative capabilities to advance by leaps and bounds, from single-soldier combat to teamwork. In the future, the combination of these two technologies may make AI like humans, able to think independently and collaborate seamlessly.

Imagine an AI assistant that not only helps you write reports, but also convenes other AIs to prepare presentations, schedule meetings, and even anticipate your needs—all starting with MCP and A2A. Their potential has just begun to emerge, and who knows what the future will bring?