Help me understand the AI agent framework landscape (Google ADK, LangGraph, CrewAI, Claude Agent SDK, OpenAI Agents SDK, etc.)

Title: Help me understand the AI agent framework landscape (Google ADK, LangGraph, CrewAI, Claude Agent SDK, OpenAI Agents SDK, etc.)

I've been diving into AI agents recently, and I'm trying to understand where each framework fits instead of just following the hype.

From what I understand so far:

• Claude Agent SDK seems focused on building coding agents (essentially exposing Claude Code programmatically).
• Google ADK appears to be a more general-purpose agent framework.
• LangGraph is often recommended for complex, stateful workflows.
• CrewAI seems centered around role-based multi-agent collaboration.
• OpenAI Agents SDK is geared toward production agents with tools, handoffs, and tracing.

But I'm still confused about how people are actually using these in production.

Some questions:

1. Which orchestration framework are you using today, and why?
2. Are LangGraph and Google ADK solving the same problem, or are they fundamentally different?
3. Where does CrewAI fit compared to LangGraph and ADK?
4. If you're using Claude Agent SDK, are you using it by itself or as one agent inside a larger orchestration framework?
5. If you were starting a greenfield project in 2026, what stack would you choose and why?
6. Are there other frameworks I should be looking at (Agno, AutoGen, Mastra, Semantic Kernel, LlamaIndex Workflows, etc.)?

I'm less interested in marketing claims and more interested in real production experience—what worked, what didn't, and what you'd choose again.

Thanks!