AI Agent Frameworks, Ranked

What's inside

'Agent framework' gets used for four genuinely different things — a Python library, a hosted runtime, a raw API, and an infrastructure platform. This guide scores all 8 on the things that actually matter for a solo builder: lock-in, cost predictability, setup overhead, and boilerplate saved.

It opens with a conversational breakdown of what you can and can't do with each option — already on AWS, committed to one model provider, want to keep your options open, deep in Google's ecosystem, or want full control — plus a capability matrix scoring 6 abilities (switch LLMs, who runs the tool-loop, typed output, managed hosting, no cloud account needed, streaming) yes/no across all 8, so you know where to look before the deep dive starts.

Every framework then gets working starter code: a Google ADK agent wired to Claude, the AWS AgentCore CLI's real setup weight, the boto3 Converse API call, a hand-rolled tool-use loop, OpenAI's three-line Agent, Anthropic's Managed Agents REST flow, LangChain's current create_agent, and a type-safe Pydantic AI agent — plus a full comparison table and decision checklist to pick between them.