Visual Studio Code 1.136 Ships With 'Agent Host' Architecture and Open Protocol
Agents now run in a dedicated process, Microsoft opens the AHP standard to third-party harnesses.
Visual Studio Code 1.136 is here, and the headline shift isn't a new UI tweak or a renderer upgrade. Microsoft has reworked how AI agents live inside the editor, introducing a dedicated Agent Host process and an open Agent Host Protocol (AHP) that lets third-party runtimes plug in. If you've ever had a Copilot session die the moment you closed the folder, this release solves that pain point.
Agents used to share the extension host with GitHub Copilot Chat and every other extension in your window. Now they run in a dedicated Agent Host process. The practical difference? Your agent sessions survive even if you close the editor window or folder that spawned them. You can also connect multiple VS Code windows to a single host, watching and controlling the same session in real time.
The host doesn't care what's driving it. The Copilot SDK, Anthropic's Claude Agent SDK, and other runtimes can all plug into a common interface. This is a fundamental change: agents are no longer a bolt-on extension. They're a core runtime component of VS Code, sitting alongside the editor itself.
The Open Protocol
Microsoft is calling the bridge between the host and its clients the Agent Host Protocol (AHP), and it's fully open. The spec uses JSON-RPC and is state-first by design. Channels are the core abstraction, meaning every session, chat, and terminal is a URI-addressable subscriber.
Client libraries are landing in Rust (ahp), TypeScript, Kotlin, Go, and Swift. Microsoft's angle here seems to be an ecosystem play similar to how MCP built one around tool calling, but for agent orchestration. You can spin up a standalone host locally with the command code agent host.
The protocol details are available on the Microsoft GitHub pages, and the architecture deep-dive from the core team drops the same day as the release.
Agent Merge and Remote Sessions
For developers who dread the final stages of a pull request, there's Agent Merge (preview). It automates the grind of getting a PR across the finish line. The agent addresses review feedback, fixes failed checks, and resolves merge conflicts in a loop until the PR is ready. Enable it via chat.agentMerge.enabled or the Agents window, then let it do the heavy lifting.
Remote work gets another boost. The Agent Host supports sessions running on another machine, accessible via SSH or dev tunnels. Desktop clients can connect to hosts on remote machines, and browser-based agents at insiders.vscode.dev/agents can join the party too. File edits and commands execute on the remote side, keeping workspace operations close to the source code.
Other Notable Changes
The Agents window gets a unified input that bundles the prompt, model selection, workspace picker, and session controls into one space. Chat sessions now form a hierarchy, with related chats appearing as children of their parent session. Multi-root workspace support is also arriving for Copilot and Claude agents, though agent hooks remain scoped to single workspace folders.
On the enterprise side, admins can require on-device transcription for dictation and block cloud transcript cleanup via policy. A new accessibility badge in the Agents window title bar helps identify sessions running in accessibility mode.
The Story of VS Code
Microsoft is also premiering "The Story of VS Code" documentary on September 4. The film covers the editor's evolution from its early beginnings to the platform millions of developers use today. It's a move that signals just how central VS Code has become to developer culture. Not many code editors get their own origin story. You can find the premiere link at aka.ms/the-story-of-vs-code.
A Shift Worth Watching
The move to a dedicated Agent Host process is arguably the most significant architectural change VS Code has made in years. Beyond session persistence, it improves security by isolating agent permissions from extension code and clears the way for a truly harness-agnostic runtime.
However, at the same time, the added layer of abstraction might make the agent experience feel less like an extension and more like a standalone service running alongside your editor. If you're keeping score, 1.136 is a strong signal that Microsoft views agents as infrastructure, not just a chat widget bolted onto the sidebar.
VS Code 1.136 is available now via the update channel or the download page.
