VS Code 1.133 moves AI agent sessions out of the editor's extension host and into a standalone Agent Host process, built on a new open-sourced specification called the Agent Host Protocol (AHP), released under MIT license. This lets agent sessions persist independently of a single editor window, be accessed remotely over SSH or dev tunnels, and stay synchronized across multiple VS Code windows using JSON-RPC with immutable state and sequenced updates. Microsoft built first-party adapters for Copilot, Claude, and Codex, and developers can now mix Anthropic and Copilot models within the same session, billing each separately. A new experimental setting allows the Agents window to open without a mandatory GitHub sign-in, currently limited to Claude. Smaller updates include sticky scroll for chat prompts and auto-refresh for local HTML files in the integrated browser. Sessions created before the update still work under the old model, and the feature can be disabled entirely.
Questions this post answers
What changed in VS Code 1.133 regarding how AI agents run in the editor?
AI agent sessions now run in a dedicated standalone process called the Agent Host instead of inside the VS Code extension host. This lets sessions persist independently of a single editor window, be reconnected to from another VS Code window, or accessed remotely over SSH or dev tunnels. Sessions created before this change keep running under the old extension-host model, and the feature can be disabled via chat.agentHost.enabled. Developers rolling out this update can track VS Code release changes and agent tooling shifts on daily.dev.
What is the Agent Host Protocol (AHP) in VS Code?
AHP is an open specification Microsoft published under the MIT license for connecting AI agents and clients through a shared session model, positioned alongside the Language Server Protocol and Debug Adapter Protocol. It uses JSON-RPC, immutable state, and pure reducers with sequence numbers to keep multiple clients synchronized to the same agent session, and is intended to let other tools and IDEs plug into the same model. Teams evaluating agent interoperability standards can follow protocol developments like AHP on daily.dev.
Can I mix Claude and Copilot models in the same VS Code agent session?
Yes, VS Code 1.133 allows mixing Anthropic and Copilot models within a single agent session. The model picker groups them under separate headings and lets you choose per turn, with Anthropic models billing against your API key and Copilot models drawing on your Copilot subscription, removing the need to reconfigure the agent host when switching providers. Developers comparing AI coding models across providers can weigh trade-offs like these on daily.dev.