TL;DR: There's no single "best" framework — the right choice depends on your agent's complexity, your team's size, and whether you need multi-agent coordination or just a solid single-agent loop. Read the quick comparison table below, then pick based on your use case. If you've been following the AI agent space, you've probably noticed the framework explosion. LangChain, LangGraph, CrewAI, AutoGen, LlamaIndex, Smolagents, and the MCP SDK itself — each claiming to be the fastest path from zero to a working agent. I've built production agents across most of these. Here's an honest breakdown of which framework wins for which scenario.…