The Complete AI Tech Stack in 2026 (Agents, MCP, A2A Explained)

What does a modern AI tech stack actually look like in 2026? In this video I build and break down a complete multi-agent system: a trip planner that plans 3 days in Lisbon in seconds — it researches the destination, checks the weather, and finds flights and hotels. It's one project that brings together just about every leading library and protocol in the AI space right now. Understand this stack, and you understand how serious AI systems are built in 2026. 🧩 What's inside: • LangGraph — the agent logic (reasoning loop) • A2A — agent-to-agent communication • MCP — tools as their own servers (RAG, weather, travel) • AG-UI — live streaming to the frontend • Mem0 — memory as its own service • Langfuse + OpenTelemetry — observability & tracing • Postgres & Qdrant — vector and state storage • FastAPI, Docker Compose — the whole thing in one docker compose up ⏱️ Chapters: 00:00 Intro 00:33 Architecture: Microservices 01:08 The Protocols (A2A, MCP, AG-UI) 02:16 The Agents 03:07 The Tools (MCP servers) 03:32 Memory with Mem0 03:57 The Databases 04:17 Observability with Langfuse 05:01 Live Demo 🔗 Full project on GitHub: https://github.com/Coding-Crashkurse/2026-AI-Stack #AI #LangGraph #MCP #AIAgents