VS Code 1.138 Brings Agents Into Dev Containers and Codex Across Two Apps
Microsoft released Visual Studio Code 1.138 on 16 September 2026, the September monthly update for the editor used by tens of millions of developers globally. The release concentrates on two themes: making AI agent sessions more portable by running them inside a project's configured Dev Container environment, and expanding the Codex harness so coding sessions can continue across the VS Code desktop and the ChatGPT web and mobile apps without losing context. A session cleanup preview adds automatic lifecycle management for completed agent sessions. Together, the three additions address a consistent developer complaint — that AI sessions are fragile, context-poor, and tethered to a single application — and move VS Code closer to an environment where AI assistance is as persistent and portable as the code itself.
Agent Sessions in Dev Containers
The headline addition in VS Code 1.138 is the ability for agent sessions to run inside a project's local Dev Container rather than in the developer's standard local environment. A Dev Container is a Docker-based development environment defined by a configuration file in the repository that specifies the operating system, language runtimes, installed tools, compilers, databases, and other project dependencies. When agent sessions run inside the container, the agent has access to the exact same tooling configured for the project — including specific Node.js or Python versions, database connections, or custom build scripts — rather than inferring what is available on the developer's local machine.
The practical impact is significant for team-wide consistency. A junior developer on Windows and a senior engineer on macOS running the same Dev Container configuration will now produce agent sessions grounded in identical tooling, reducing the class of environment-dependent inconsistencies that erode trust in AI-generated code. Docker is required for this feature, and Microsoft is rolling it out gradually rather than enabling it universally on day one.
Why Dev Container Agents Matter for Large Teams
For software teams maintaining multiple repositories across different stack configurations — common in microservices-based architectures and in enterprise codebases with heterogeneous services — the Dev Container agent feature is particularly valuable. An agent session debugging a Python data pipeline should be running inside the container that has the pipeline's specific Python 3.11 environment, its database adapters, and its test data fixtures, not in a general-purpose developer environment that happens to have Python installed. VS Code 1.138 makes this the default behaviour when a Dev Container configuration is present.
Cross-App Codex Sessions
VS Code 1.138 expands how Codex sessions — the longer-running coding task sessions built on OpenAI's Codex model — can move between applications. A developer who begins a Codex session in the ChatGPT app on a phone or browser can now continue that same session in VS Code on their desktop, with full access to VS Code's built-in tools, installed extension tools, and MCP-connected external tools. The reverse also applies: a session started in VS Code can continue in the ChatGPT app when the developer moves away from their desk.
Where a developer holds both a GitHub Copilot subscription and a ChatGPT subscription, VS Code 1.138 allows switching between models from both providers using the model picker within a single conversation, without losing session state. This is a material architectural shift from earlier releases where the agent model selection was fixed at session start — it gives developers the ability to route different steps within one task to different models based on their respective strengths.
Session Cleanup Preview
VS Code 1.138 introduces a session cleanup feature in preview. When a pull request associated with a coding agent session is merged, VS Code automatically marks that session as done and, optionally, deletes it after a configurable grace period. The release also adds a completion confetti animation as a deliberate UX signal that a session has concluded, alongside session list badges that surface sessions needing attention at a glance. The cumulative goal is to keep the sessions panel legible as long-running coding agent use grows and developers accumulate more completed sessions.
Browser-addressable links for Agent Host sessions accompany the cleanup feature. A specific session can now be referenced via a stable URL that opens it from another app, a GitHub issue comment, or terminal output, making it straightforward to hand off or resume a session without navigating back through the VS Code UI.
What VS Code 1.138 Means for Indian Engineering Teams
India has one of the largest VS Code user bases globally, with the editor standard across full-stack, backend, cloud, and AI development workflows. The Dev Container agent sessions feature is particularly relevant for Indian software services teams delivering projects where clients specify exact environment configurations — common in banking, insurance, and government technology projects. Consistent agent output across environments reduces one category of variability in AI-assisted delivery and makes it easier to demonstrate reproducible results to clients who care about environment integrity.
The cross-app Codex improvement is a workflow accelerator for developers who move between devices during the working day — a pattern common in India's hybrid working culture where developers context-switch between a work laptop and a personal phone. Starting a coding discussion on mobile and continuing it in VS Code without losing context removes a real friction point in multi-device AI-assisted development.
For teams building developer tooling or internal platforms on top of VS Code's extension ecosystem, the agent protocol improvements in 1.138 — addressable session links, cross-app continuity, model switching within sessions — provide a richer set of primitives for integrating AI assistance into custom workflows and automation pipelines.
The Bottom Line
VS Code 1.138, released on 16 September 2026, delivers three additions: agent sessions inside Dev Containers so AI operates within the project's configured tools and dependencies rather than the developer's local environment; cross-app Codex sessions that continue between VS Code and the ChatGPT app with mid-session model switching between Copilot and ChatGPT subscriptions; and a session cleanup preview that auto-archives completed sessions and adds browser-addressable session links. For Indian engineering teams, Dev Container agent sessions improve consistency across team environments and client-specified configurations, while cross-app Codex and addressable session links reduce friction in multi-device and collaborative AI development workflows.
Frequently Asked Questions
What are the main features in VS Code 1.138 released on 16 September 2026?+
VS Code 1.138, released on 16 September 2026, introduces three key additions. First, agent sessions can now run inside a project's local Dev Container, giving the AI access to the project's configured tools, language runtimes, and dependencies rather than the developer's general local environment; Docker is required and the feature is rolling out gradually. Second, Codex sessions can continue across VS Code and the ChatGPT app, allowing developers to start a coding task on one platform and continue it on another, with the ability to switch between GitHub Copilot and ChatGPT model subscriptions from within a single session. Third, a session cleanup preview automatically marks agent sessions as done when their associated pull requests are merged, with optional deletion after a grace period, confetti completion animation, and session list badges for sessions needing attention.
How do Dev Container agent sessions work in VS Code 1.138?+
In VS Code 1.138, when a project has a Dev Container configuration file, agent sessions can run inside that container rather than the developer's default local environment. A Dev Container is a Docker-based environment defined in the repository that specifies the exact operating system, language runtimes, installed tools, compilers, database connections, and other project-specific dependencies. Running the agent inside the container means it operates with the same tooling any contributor to that project uses — a specific Python 3.11 environment, a particular version of Node.js, or project-specific database adapters — instead of inferring environment state from an arbitrary developer machine. This improves consistency of AI-generated code across developers on different machines and operating systems. Docker must be installed, and the feature is rolling out gradually to users.
What is cross-app Codex in VS Code 1.138 and how does it work?+
Cross-app Codex in VS Code 1.138 means that coding sessions using OpenAI's Codex model can continue across the VS Code desktop application and the ChatGPT web or mobile app without losing context. A developer who starts a Codex session in the ChatGPT app on their phone can switch to VS Code on their desktop and continue from the same point, with access to VS Code's built-in tools, installed extensions, and MCP-connected tools. The session can move back to the ChatGPT app as well. Developers who hold both a GitHub Copilot subscription and a ChatGPT subscription can also switch between models from both providers using the model picker within the same session — for example, using one model for code generation and another for documentation — without restarting the session or losing conversation history.
What does VS Code 1.138 mean for Indian software development teams?+
VS Code 1.138 has three practical implications for Indian engineering teams. Dev Container agent sessions are most valuable for software services teams working on client projects with specified environment configurations — common in banking, insurance, and government technology projects — where consistent, environment-accurate AI output matters. Cross-app Codex sessions benefit developers who move between devices during the working day, a common pattern in India's hybrid working culture, since a coding thread started on mobile can continue in VS Code without losing context. For teams building developer tooling or internal automation platforms, the new browser-addressable session links and cross-app continuity provide richer primitives for integrating AI assistance into custom workflows. The session cleanup preview reduces session management overhead as agent-assisted development scales within engineering teams.
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TechPillow Team
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