Visual Studio’s Copilot BYOM now needs the new Agent, and Ollama setups must be redone

GitHub has shipped its September update for Copilot in Visual Studio 2026. The most consequential change is a breaking one: Bring Your Own Model now works only in the new Agent (Preview), and Ollama models must be added again.

Three changes in Visual Studio 2026

The update has three headline items. First, the Git agent can now explore a pull request. A developer opens GitHub Copilot Chat, selects the Git agent and attaches a pull request as context from the Git Repository window. Copilot then returns a summary with links that lead to the underlying comments and files.

That feature depends on the MCP server of the team’s Git provider. GitHub and Azure DevOps are both supported, according to the post, but the connection has to be set up first.

Second, NuGet Audit warnings in the Error List now carry a fixer action. It opens Copilot Chat in agent mode and asks Copilot to repair the vulnerable packages through the NuGet MCP server. Two conditions apply: the user must be signed in to GitHub Copilot, and the NuGet MCP server must be switched on from the Copilot Chat tools menu.

Third, Bring Your Own Model (BYOM) changes. It remains in preview. GitHub says it lets teams use the models they prefer, either through GitHub Copilot or through their own deployments, and that it works whether or not the user is signed in to GitHub. It is on by default in the Community, Professional and Enterprise editions of Visual Studio. The listed providers are Microsoft Foundry, OpenAI, Anthropic and Ollama.

Why existing BYOM users have work to do

The breaking change is easy to miss in a monthly roundup. BYOM now requires the new Agent (Preview), which GitHub describes as built on a harness powered by the GitHub Copilot SDK. The earlier Ask and Agent modes no longer support BYOM. Anyone who configured Ollama models before updating has to add them again.

The post does not say what the new harness changes in practice. It gives no information on tool-calling behavior, performance, or whether a model that worked in the old Agent mode will behave the same way in the new one. Teams that run local or self-hosted models through Ollama should expect to test their setups after updating rather than assume parity.

Who gets it, and what the post leaves open

GitHub says the update is available on every Copilot plan: Free, Student, Pro, Pro+, Max, Business and Enterprise. Visual Studio 2026 can be downloaded now, and the Insiders channel carries the latest builds. The post names no regions and no extra price, and it makes no claim about speed or accuracy gains. The pull request summaries and NuGet fixes are described only by what they do, so how well they work is not established by the source.

The pull request feature also adds a requirement that existing chat users did not have before: an MCP connection to the Git host. For organizations that manage tool access centrally, that is an administrative step, not a toggle inside the editor.

A setup burden that arrives as admin controls tighten

The timing is worth reading alongside other Copilot news this week. As we reported, GitHub is applying its global default to eligible Copilot features that Business and Enterprise admins left unconfigured, with enforcement running from October 22 through October 26 after a 28-day grace period. Features an admin set explicitly are left alone.

For Visual Studio teams, the two stories meet in the MCP servers. Both the pull request exploration and the NuGet fixer rely on MCP, and the global default covers a policy for MCP servers in Copilot. An admin who never chose a value for that setting may find that the behavior depends on the enterprise default rather than on the developer’s preference. GitHub has not said how the default interacts with these Visual Studio features, so the safest reading is that teams should check their policy pages before assuming the new actions will work.

The third point of context is the scale of the change. BYOM spans four named providers, and the update moves all of them onto one Agent mode. That narrows where the feature runs, even as the provider list stays wide, and it means the old Ask mode is no longer a route to a custom model.