--- title: MCP vs A2A vs ACP: How AI Agents Actually Talk to Each Other description: A newsletter covering several system design topics. The main piece explains three AI agent communication protocols: MCP (agent-to-tool), A2A (agent-to-agent),... canonical: https://daily.dev/posts/mcp-vs-a2a-vs-acp-how-ai-agents-actually-talk-to-each-other-oigkmdz7m twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: MCP vs A2A vs ACP: How AI Agents Actually Talk to Each Other | daily.dev og:description: A newsletter covering several system design topics. The main piece explains three AI agent communication protocols: MCP (agent-to-tool), A2A (agent-to-agent),... og:url: https://daily.dev/posts/mcp-vs-a2a-vs-acp-how-ai-agents-actually-talk-to-each-other-oigkmdz7m og:image: https://api.daily.dev/og/posts/OIGKmDZ7M.png og:image:alt: MCP vs A2A vs ACP: How AI Agents Actually Talk to Each Other 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. # MCP vs A2A vs ACP: How AI Agents Actually Talk to Each Other **[ByteByteGo](https://daily.dev/sources/bytebytego)** · 6 min read · 4 upvotes · 0 comments ## Summary A newsletter covering several system design topics. The main piece explains three AI agent communication protocols: MCP (agent-to-tool), A2A (agent-to-agent), and ACP (REST-based agent-to-agent, now merged into A2A), noting MCP and A2A are complementary in production. Additional sections cover evaluation strategies for LLMs, RAG pipelines, coding agents, and multi-agent systems; a roundup of eight notable open-source frontier models; a high-level overview of distributed tracing with OpenTelemetry; and an explanation of Redis persistence mechanisms (AOF, RDB, and mixed approach). ## 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, A2A, and ACP for AI agent communication? MCP handles agent-to-tool communication: a host app's embedded MCP client routes requests to an MCP server, which executes the tool call and returns a structured response. A2A handles agent-to-agent communication, where an agent discovers a peer via its Agent Card and delegates tasks, pausing in an input-required state if more input is needed. ACP took a REST-first approach with peer discovery via an Agent Manifest and has since been merged into A2A. In production, MCP and A2A are typically used together, complementing rather than replacing each other. _daily.dev helps engineers designing agent stacks track how MCP, A2A, and ACP fit together._ ### How does Redis persist data to disk to prevent data loss on restart? Redis uses two mechanisms: AOF (Append-Only File) and RDB (Redis Database) snapshots, often combined in production. AOF executes commands in memory first, then logs them to disk non-blocking, replaying the log on recovery. RDB periodically snapshots the full dataset using a forked bgsave subprocess and copy-on-write, giving fast reloads. RDB provides fast reloads while AOF guarantees durability since the last snapshot. _Engineers tuning Redis durability trade-offs can follow deep dives like this on daily.dev._ ## Similar posts on daily.dev - [Model Context Protocol \(MCP\) vs. Agent2Agent \(A2A\): which protocol do you need?](https://daily.dev/posts/model-context-protocol-mcp-vs-agent2agent-a2a-which-protocol-do-you-need--e1acol0ht) · Redis · 1 upvotes · 0 comments - [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 --- Tags: [#devops](https://daily.dev/tags/devops), [#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/mcp-vs-a2a-vs-acp-how-ai-agents-actually-talk-to-each-other-oigkmdz7m) ```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":"MCP vs A2A vs ACP: How AI Agents Actually Talk to Each Other","url":"https://daily.dev/posts/mcp-vs-a2a-vs-acp-how-ai-agents-actually-talk-to-each-other-oigkmdz7m","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/mcp-vs-a2a-vs-acp-how-ai-agents-actually-talk-to-each-other-oigkmdz7m"},"datePublished":"2026-07-18T16:52:52.840Z","dateModified":"2026-09-14T06:02:10.240Z","description":"A newsletter covering several system design topics. 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