Which AI Framework Should You Use?
There are now many frameworks for LLM apps and agents, and they overlap. The good news: the core ideas (prompts, tools, retrieval, loops, memory, tracing) are the same everywhere. Learn them once with LangChain and LangGraph, and you can pick up any other framework in a day. Here is how they compare, and how to choose.
In this session
- The same five building blocks in every framework
- Nine popular frameworks side by side
- An interactive chooser
- When to use no framework at all
01The same building blocks everywhere
02Nine frameworks side by side
| Framework | Core idea | Best for | Languages |
|---|---|---|---|
| LangChain | standard parts + create_agent | LLM apps, RAG, single agents | Python, JS/TS |
| LangGraph | graph of nodes, edges and saved state | custom workflows, approvals, multi-agent | Python, JS/TS |
| LlamaIndex | data framework: parse, index, query | chat with documents, knowledge assistants | Python, TS |
| CrewAI | role-based “crews” of agents with tasks | quick multi-agent prototypes (research, content) | Python |
| Microsoft Agent Framework | successor to AutoGen and Semantic Kernel | Azure and .NET shops, multi-agent chat | Python, .NET |
| OpenAI Agents SDK | agents, handoffs, guardrails, tracing | lightweight agents on OpenAI models | Python, JS/TS |
| Google ADK | Agent Development Kit, agent hierarchies, A2A | Google Cloud / Gemini, multi-language teams | Python, Java and more |
| Pydantic AI | type-safe agents with validated outputs | structured extraction, typed Python codebases | Python |
| Claude Agent SDK | the agent loop behind Claude Code: files, shell, subagents | coding and computer-task agents on Claude | Python, TS |
Landscape as of late 2026; check each project’s docs for its current version.
03Choose with your requirements
| Question to ask | Why it matters |
|---|---|
| Do I need loops or approvals? | if not, a chain or plain SDK call is enough |
| Which models must I support? | single-vendor SDKs lock you to one provider |
| How will I debug it? | tracing (LangSmith, provider dashboards, OpenTelemetry) is essential for agents |
| Who maintains it? | large, active projects get security fixes and new model support quickly |
| Can I test it? | explicit workflows are much easier to unit-test than free-roaming agents |
04When to use no framework
Frameworks save time, but every layer adds something to learn and debug. Use plain provider SDKs when the app is a single call, a short fixed chain, or performance-critical. Many production teams start with the SDK, then adopt LangGraph when they need checkpoints and approvals.
05Summary
- All frameworks share the same blocks: model, tools, knowledge, control flow, memory + tracing.
- LangChain for parts and simple agents, LangGraph for controlled workflows, LlamaIndex for data-heavy RAG.
- CrewAI for quick multi-agent prototypes; Microsoft Agent Framework for Azure/.NET; OpenAI Agents SDK, Google ADK and Claude Agent SDK for their ecosystems.
- For one simple call, skip the framework.
06Quick quiz
1. Which framework is the successor to AutoGen and Semantic Kernel?
2. Best fit for strict workflows with human approval?
3. Best fit for a document-heavy knowledge assistant?
4. When should you skip frameworks?
5. What stays the same across frameworks?
07References
- Microsoft: Migrate Semantic Kernel and AutoGen projects to Agent Framework
- CrewAI docs
- OpenAI Agents SDK
- Google Agent Development Kit
- Pydantic AI
- Claude Agent SDK