Microsoft Releases VS Code 1.138 with Dev Container AI Agent Sessions
Microsoft released VS Code version 1.138, introducing support for running AI agent sessions inside local Dev Containers and expanding Codex harness integration. The update also adds a preview feature for session cleanup to streamline completed agent workflows after merging pull requests. Running AI agents inside isolated Dev Containers ensures that autonomous coding agents only use project-specified tools and dependencies, protecting the host machine. Furthermore, expanded Codex harness integration allows seamless continuation of ChatGPT conversations directly inside the IDE across both Copilot and ChatGPT subscriptions. Enabling agent sessions in Dev Containers requires Docker and setting `chat.agentHost.devContainer.enabled` to true. The expanded Codex harness lets models invoke VS Code built-in tools, extension utilities, Model Context Protocol (MCP) tools, and inline image generation.
## BACKGROUND
A development container (Dev Container) allows developers to build and test code inside Docker containers configured with exact runtime environments and tools. As software development tools increasingly integrate autonomous AI agents that make edits and run commands, isolated execution environments have become critical for safety and consistency.