What Is a Multi-Agent System? Patterns, Frameworks, and When to Actually Use One
In 2026, the AI agent conversation has shifted from "one super-agent" to "a team of agents with different roles." Anthropic Research, Claude Code subagents, Devin, and Cursor's parallel workers are all multi-agent. This article covers the definition, the five core architecture patterns (orchestrator, handoff, hierarchical, peer-to-peer, pipeline), a comparison of the big-four frameworks (Claude Agent SDK / OpenAI Agents SDK / LangGraph / Strands), production examples, the cost structure (Anthropic reports ~15x tokens), when to use it and when not to, and design best practices — all grounded in official sources.