Microsoft Agent Framework 1.0: Migration Is the Real Test

What shipped

Microsoft released Agent Framework 1.0 on April 3, 2026. The SDK folds two of the company's best-known open-source AI projects, Semantic Kernel and AutoGen, into one production toolkit for .NET and Python.2 Microsoft calls it the stable, production-ready milestone, with stable APIs and long-term support in both languages.4 It builds on the framework Microsoft first introduced in October 2025, combining Semantic Kernel's foundations with AutoGen's orchestration ideas.4

The headline features center on multi-agent coordination. Version 1.0 ships five orchestration patterns: sequential, concurrent, handoff, group chat, and Magentic-One. Magentic-One is the generalist orchestrator from AutoGen's research team, now built into the SDK.2 There is also a graph-based Workflows engine for explicit control over multi-agent execution. It borrows conceptually from LangGraph and is wired into Microsoft's telemetry stack.2 Around that stable core sit preview features, including DevUI, hosted agent integration, and expanded tooling and observability.4

Why Microsoft consolidated

The merger fixes a problem Microsoft created for itself. Through 2025, the two frameworks drifted toward each other. Semantic Kernel picked up agent abstractions, and AutoGen added filters and telemetry. Developers ended up comparing overlapping release notes to decide which project had the feature they needed that week.2 Microsoft frames the unified SDK as a successor path that builds on both projects' ideas rather than throwing them away.4

The practical result is that there is now one first-party answer. Semantic Kernel and AutoGen are in maintenance mode. As one .NET developer put it, anyone starting new agent work on Microsoft's stack has no other first-party option.1 That developer also noted that the framework is largely built by the former Semantic Kernel team, which gives it continuity.1

The migration math

The more consequential question for teams already in production is how hard it is to move. Semantic Kernel 1.77.0, released May 28, 2026, will keep getting critical bug and security fixes for at least a year after Agent Framework's general availability. All new features, however, now land only in the new framework.3 For teams with existing code, that means a deadline even if nothing breaks tomorrow.

One migration guide argues the work is mostly mechanical, not conceptual. A small Semantic Kernel agent with one Kernel, a few plugins, and one ChatCompletionAgent is estimated at roughly a half-day job, because the concepts map one-to-one.3 The friction comes from details:

• Message and content types shift from Semantic Kernel's ChatMessageContent to Microsoft.Extensions.AI.
• Thread creation moves from the caller to the agent.
• Every dependency-injection registration that hung off Kernel must be re-pointed at AIAgent.3

The same guide describes much of this as find-and-replace with the compiler catching mistakes.3 It also points to a real design improvement: the framework drops Semantic Kernel's "god-object" Kernel, which every agent previously had to route through. Agents can now be created directly from an IChatClient.3

That half-day estimate applies to small apps. Larger codebases with many plugins, custom DI graphs, and code that depends on Semantic Kernel's content types will likely take proportionally longer. The work is still predictable, but it is not free.

How it feels in practice

Early community feedback is cautiously positive. A developer who followed the project since its release-candidate phase called tool-calling, orchestration graphs, and the agent abstraction solid. They added that, unusually, the .NET experience doesn't feel like a Python port with C# syntax.1 The weaknesses they named were thin documentation beyond introductory examples, an immature extension ecosystem, and the fact that most interesting examples online are still written in Python.1 They described DevUI as useful for debugging agent flows but clearly still a preview.1

That developer's view on whether .NET shops should move to Python for agent work was that the gap has narrowed considerably. In their assessment, the core SDK surface is now comparable.1 Python's advantage, they argued, lies in the surrounding ecosystem of vector stores, embedding pipelines, and evaluation frameworks.1

The takeaway

The feature list confirms where Microsoft wants agent development to go. The more telling part of the story is the migration path. By putting both predecessors into maintenance mode and setting a support window, Microsoft has made adoption a scheduling question rather than a choice for existing Semantic Kernel users. The mechanical nature of the port lowers the cost of moving, and that may matter more to adoption than any new orchestration pattern.

The bigger open question is ecosystem depth. A stable API and long-term support are necessary, but .NET teams will judge the framework partly on whether documentation, extensions, and tooling catch up to what Python developers already have.