VS Code 1.138 ships Agent Host architecture, lets Codex sessions continue across ChatGPT
dfinke · x · 2026-09-17
VS Code 1.138 introduces the Agent Host architecture: agent harnesses now run in a dedicated process speaking the Agent Host Protocol (AHP), so sessions live independently of editor windows and multiple clients can attach to the same session.
Key changes:
- Agent Host: agents run in their own process (local utility process or remote server), unblocked by busy extensions
- Expanded Codex harness: continue Codex sessions between ChatGPT and VS Code, choose Copilot or ChatGPT subscription, and access the VS Code tool ecosystem — filesystem, terminal, extensions, MCP
- Agent sessions in Dev Containers with project tools and dependencies
- Automations enabled by default, exportable/importable across teams
- Session cleanup (Preview): auto-mark merged sessions done with optional grace-period deletion
The author frames this as the beginnings of a general-purpose agent runtime — a Client → Agent Host → Harness → Model → Tools stack where pluggable harnesses share one host.
Related event: VS Code 1.138 introduces Agent Host architecture for cross-client AI agents(2 posts)→
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