--- title: Model Context Protocol (MCP) vs. Agent2Agent (A2A):... description: MCP and A2A are two complementary protocols for AI agent architectures that solve different problems. MCP connects agents to tools and data via a hierarchical... canonical: https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Model Context Protocol (MCP) vs. Agent2Agent (A2A): which protocol do you need? | daily.dev og:description: MCP and A2A are two complementary protocols for AI agent architectures that solve different problems. MCP connects agents to tools and data via a hierarchical... og:url: https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht og:image: https://api.daily.dev/og/posts/e1acol0HT.png og:image:alt: Model Context Protocol (MCP) vs. Agent2Agent (A2A): which protocol do you need? og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Model Context Protocol (MCP) vs. Agent2Agent (A2A): which protocol do you need? **[Redis](https://daily.dev/sources/redislabs)** · 11 min read · 1 upvotes · 0 comments ## Summary MCP and A2A are two complementary protocols for AI agent architectures that solve different problems. MCP connects agents to tools and data via a hierarchical client-server model, while A2A enables peer-to-peer communication between independent agents owned by different teams or organizations. The key decision factor is ownership: use A2A when agents cross trust boundaries you don't control, and use in-framework orchestration (LangGraph, CrewAI) when all agents are under one team's control. Both protocols leave state management, observability, memory, and performance optimization to the developer. The post also covers gaps neither protocol addresses — correlating workflow state, end-to-end tracing, tool overload in MCP, and the absence of a standard agent memory interface — before introducing Redis Iris as a context and memory layer that works with both protocols. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the difference between MCP and A2A protocols for AI agents? MCP connects an agent to its own tools and data through a hierarchical client-server model where an agent calls a passive server; A2A connects independent agents owned by different teams or vendors through a peer-to-peer model with stateful, long-running tasks. MCP uses tools, resources, and prompts as primitives, while A2A uses Agent Cards, Tasks, and Artifacts, both running JSON-RPC over HTTP. _Teams weighing agent architecture tradeoffs can track protocol comparisons like this one on daily.dev._ ### Do I need the A2A protocol if my team builds all the agents in-house? Generally no. A2A's overhead in setup, authentication, and moving parts only pays off when agents cross a real security or permission boundary owned by a different team, vendor, or company. When all agents run under one team's control with shared permissions, an orchestration framework like LangGraph or CrewAI can coordinate them without a network protocol in the middle. _Architects deciding between A2A and simple orchestration can follow this kind of guidance on daily.dev._ ### How much of an AI agent's runtime is spent thinking versus calling tools? In one analysis of agent workloads, the model's own reasoning consumed 69.4% of total time on average, while tool execution took the remaining 30.2%. Because each step waits on the other, these phases can't be overlapped much, and adding more MCP tools compounds the cost by eating into the model's context window with tool descriptions, eventually degrading tool selection accuracy. _Engineers optimizing agent latency and cost can find workload benchmarks like this on daily.dev._ ## Similar posts on daily.dev - [A2A vs MCP - How These AI Agent Protocols Actually Differ](https://daily.dev/posts/a2a-vs-mcp---how-these-ai-agent-protocols-actually-differ-t0us6ejof) · DigitalOcean Community · 2 upvotes · 0 comments - [5 agent architecture scenarios: assess MCP vs. A2A](https://daily.dev/posts/5-agent-architecture-scenarios-assess-mcp-vs-a2a-bzpmtwwbs) · Redis · 1 upvotes · 0 comments - [A2A vs MCP 2026: How AI Agents Talk to Each Other](https://daily.dev/posts/a2a-vs-mcp-2026-how-ai-agents-talk-to-each-other-fnpu1gxlr) · Alex CloudStar · 0 upvotes · 0 comments - [MCP and A2A: A Network Engineer’s Mental Model for Agentic AI](https://daily.dev/posts/mcp-and-a2a-a-network-engineer-s-mental-model-for-agentic-ai-l74fjxbsd) · Cisco · 1 upvotes · 0 comments --- Tags: [#ai-agents](https://daily.dev/tags/ai-agents), [#mcp](https://daily.dev/tags/mcp), [#redis](https://daily.dev/tags/redis) [View this post on daily.dev](https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Model Context Protocol (MCP) vs. Agent2Agent (A2A): which protocol do you need?","url":"https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht"},"datePublished":"2026-07-23T00:08:24.609Z","dateModified":"2026-09-14T08:46:18.061Z","description":"MCP and A2A are two complementary protocols for AI agent architectures that solve different problems. 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