Microsoft just laid out its biggest push yet to make Windows a first-class platform for local AI development. At the center of the announcement: a new family of on-device language models called Aion, a policy-driven sandbox for AI agents baked into the OS, and a hardware lineup capable of running trillion-parameter models on a desk.

The pitch is what Microsoft is calling unmetered intelligence: push as much of the agentic workload as possible onto the device so token bills do not balloon, and reserve frontier models for tasks that actually need them.

Meet Aion 1.0: two models, two jobs

Aion is Microsoft's next generation of small language models purpose-built to run on Windows. It comes in two flavors with very different missions.

Aion 1.0 Instruct is the workhorse. It is Microsoft's next-generation small language model, smaller, faster and more efficient than the current Windows OS SLM, designed from the ground up for on-device workloads. It targets the bread-and-butter text tasks: summarization, rewrite, intents, and accessibility. Crucially, developers can start experimenting with Aion 1.0 Instruct in preview today in Edge Insider channels and as an open source model in July on Hugging Face.

Aion 1.0 Plan is the more interesting beast for anyone building agents. It is a 14-billion parameter reasoning and tool-calling model with 32K context length that ships in-box as part of Windows on capable devices. It enables applications to reason over user intent, invoke tools, manage files and orchestrate sub-agents, bringing fully agentic workflows onto the device.

The split is intentional. Instruct handles cheap, high-volume text intelligence. Plan handles the planner-executor loop that today usually round-trips to a cloud model.

Windows AI APIs break out of NPU jail

One of the quieter but more consequential changes: the built-in Windows AI APIs are no longer locked to Copilot+ PCs with NPUs. Windows AI APIs are expanding beyond NPUs to CPUs and GPUs, bringing local AI experiences to a much broader set of Windows 11 devices. The existing Windows inbox SLM is now available on capable GPUs, and Video Super Resolution and Speech Recognition on CPUs, all in public preview.