Choosing the Right AI SDK: Foundry vs Copilot vs OpenAI

Your Leadership Wants “the Best One”

Every architecture review I’ve sat in this year eventually hits the same question: “Which AI agent SDK should we use?” And every time, someone wants a single answer. Foundry. Copilot. OpenAI. Pick one.

That’s the wrong framing. BMW achieved 12× faster data analysis with Foundry Agent Service. I built an SRE agent with GitHub Copilot SDK in two hours. Commerzbank handles 30,000+ monthly agent conversations in a regulated banking environment. All three SDKs. All three successful. The difference isn’t capability — it’s constraints.

Give your leadership this instead: the one that matches your constraints TODAY with the least rewrite risk for where you’re headed.

The 3-Question Decision Tree

I boil the choice down to three questions. Answer them in order, and you’ll land in the right place.

Question 1: “Do we need enterprise governance TODAY?”

If you’re in a regulated industry — finance, healthcare, government — and compliance isn’t a roadmap item but a launch blocker, the answer is Azure AI Foundry Agent Service. It ships with native Microsoft Purview integration, Content Safety, and Entra Agent ID out of the box. The Foundry Control Plane gives you a single pane for building, operating, and governing your entire agent estate.

Commerzbank’s AI agent Ava resolves 75% of customer requests autonomously — in one of the world’s most regulated banking environments. That’s the kind of compliance-first architecture Foundry enables.

Question 2: “Do we want orchestration solved for us?”

If you’re already in the GitHub ecosystem and want to embed agentic capabilities without building a platform from scratch, GitHub Copilot SDK is the play. It exposes the same agentic core that powers GitHub Copilot CLI — planning, tool calls, MCP support, state management, streaming — as a programmable layer in Node.js, Python, Go, and .NET.

Authentication and model routing are handled automatically. You write your product logic; the SDK handles the orchestration plumbing. When I built my SRE agent, I went from zero to a working prototype with MCP server integration in two hours. No custom planner, no tool loop wiring, no auth boilerplate.

Question 3: “Do we want maximum flexibility with minimal abstraction?”

If you need multi-cloud portability, want to avoid platform lock-in, or you’re a startup iterating fast, the OpenAI Agents SDK is the answer. It gives you four primitives — Agents, Tools, Handoffs, and Guardrails — and gets out of your way. It’s open-source under MIT, supports 100+ LLMs via LiteLLM, and you pay only for API calls.

The SDK evolved from OpenAI’s experimental Swarm framework into a production-ready system with built-in tracing for debugging agent workflows. Need durability guarantees? The official Temporal integration gives you crash-proof execution without added code complexity.

Side-by-Side Comparison

For a deeper feature-by-feature breakdown, the Microsoft AI Decision Framework provides an excellent reference, and this DEV.to comparison covers the Copilot SDK vs Foundry nuances well.

The Question Nobody Asks: Rewrite Risk

Every SDK locks you into something. The real question is: what’s the cost of changing your mind later?

Foundry is the right bet if you’re already Azure-invested. The lock-in is real, but so is the value — you aren’t rebuilding compliance from scratch. Copilot SDK ties you to GitHub’s model curation, which is fine if you trust their roadmap (I do). OpenAI Agents SDK gives you full portability, but you own the hosting, monitoring, and compliance tooling.

My rule of thumb: if your team would need more than two sprints to migrate away from an SDK, you’re locked in. Plan accordingly.

Microsoft’s Layered Strategy: They’re Not Competing

Here’s what most comparison articles miss: these SDKs occupy different layers of the same stack. As Microsoft’s own decision framework explains:

• Copilot SDK puts Copilot inside your app
• Microsoft Agent Framework lets you build your app out of agents
• Foundry provides the managed platform and governance underneath both
• OpenAI SDK exists for the open ecosystem — Microsoft benefits either way through Azure OpenAI hosting

The Semantic Kernel integration announced in January 2026 makes this concrete: you can compose Copilot SDK agents alongside Azure OpenAI agents within the same Agent Framework, swapping providers without restructuring your code.

The recent rebrand from “Azure AI Foundry” to “Microsoft Foundry” signals that agents are first-class citizens across the entire Microsoft ecosystem, not just Azure. And Agent 365 unifies governance through Defender, Entra, Intune, and Purview — managing agents the same way enterprises manage users.

When to Use What: Quick Reference

The Bottom Line

There’s no “best” SDK — there’s the one that matches your constraints today with the least rewrite risk for where you’re headed tomorrow. Start with the decision tree. Answer three questions honestly. Ship the agent that solves a real problem this sprint, not the one that looks best on an architecture slide.

The teams shipping production agents right now aren’t debating frameworks. They picked one, built something, and iterated. BMW didn’t spend six months evaluating — they deployed multi-agent AI on Foundry and got 12× faster results. I didn’t overthink my SRE agent — I picked Copilot SDK, had it running in two hours, and moved on to the next problem. That’s the play.