Analyzing GitHub Copilot Weekly Releases – September 21 Based on Official Information

This article is a technical explanation and implementation example generated using AI. The presented code and procedures are based on primary sources, but have not been verified on actual hardware by the author. Behavior may vary depending on the environment and version.

The GitHub Copilot weekly release (September 21) announced the addition of new AI models, the introduction of a local sandbox feature in the desktop app, and various feature extensions in Slack, Microsoft Teams, JetBrains, and VS Code. This article safely and practically organizes the changes in each environment based on primary sources, explaining each functional element and key points for usage.

Purpose and Limitations of This Article

The purpose of this article is to accurately grasp the overall picture of features added and updated in each component based on the official GitHub Changelog. Since it is [Pending Verification on Actual Hardware], actual screen displays and command output results are not explicitly shown, and the explanation is limited to the specifications and components described in the official information. In addition, for verification involving Windows environments or specific GUI operations, we proceed on the premise that behavior may vary depending on environmental differences and versions.

Overall Picture Confirmed from Official Information

This release includes updates across a wide range of areas, from the addition of core models to sandbox features in various IDEs, chat tools, and desktop applications. The following diagram illustrates the primary update areas mentioned in the primary source.

flowchart TD
    A[GitHub Copilot Weekly Releases] --> B[GitHub Copilot Core]
    A --> C[GitHub Copilot App]
    A --> D[Slack & Microsoft Teams]
    A --> E[JetBrains IDEs]
    A --> F[VS Code 1.139]

    B --> B1[Claude Opus 5.5 / GPT-6 Sol / GPT-6 Luna / Grok 4.7]
    C --> C1[Local Sandboxing & OpenTelemetry]
    D --> D1[Model Selection & Issue Duplication Check]
    E --> E1[Assisted Approvals & Session Rewind]
    F --> F1[Dev Containers & Compact View]

Addition of GitHub Copilot Core Models

Available AI models have been expanded across GitHub Copilot plans (Pro, Pro+, Max, Business, and Enterprise). Available models vary by plan.

• Claude Opus 5.5: Available in Copilot Pro+, Max, Business, and Enterprise plans.

• GPT-6 Sol: Available in Copilot Pro+, Max, Business, and Enterprise plans.

• GPT-6 Luna: Available in Copilot Pro, Pro+, Max, Business, and Enterprise plans.

• Grok 4.7: Available in Copilot Pro, Pro+, Max, Business, and Enterprise plans.

[Scheduled for verification in Windows environment] These new model identifiers are expected to become available when specifying models via API or CLI, but detailed schemas and configuration methods require checking official individual documentation.

GitHub Copilot App Feature Enhancements

Security and monitoring features have been enhanced in the GitHub Copilot desktop application.

1. Local Sandbox (Public Preview)The local sandbox feature is available in public preview to enhance safety by restricting the files, network, and credentials that agents can access.

2. Tracing Agent Activity with OpenTelemetryYou can now configure agent activity tracking through enterprise management settings and monitor it using existing observability tools.

Slack and Microsoft Teams Integration Updates

The usability of Copilot in collaboration tools has been improved.

• Dynamic Model Switching: You can switch to the model best suited for the task mid-conversation, and the switched model is maintained for the remainder of the thread. In Slack, default settings per channel are also supported.

• Prevention of Duplicate Issues: Automatically checks for similar existing issues before creating a new one.

• Improved Traceability for Long-Running Tasks: Implementation plan status display has been clarified, making recovery from interruptions or stale responses, and reconnection from idle states, more predictable.

• Context Expansion (Slack): You can pass more context by sharing supported files, attachments, and message links.

Copilot for JetBrains Updates

Handling of agent sessions and custom instructions in the JetBrains environment has been improved.

• Assisted Approvals (Public Preview): In agent sessions, low-risk tool calls are automatically approved, and users are prompted only for high-risk actions.

• Session Rewind: When changing the direction of an agent session by editing a previous message, both the conversation and file modifications are automatically rolled back before sending the new request.

• Shared Organization/Enterprise Skills, Custom Instructions: In addition to organization management custom instructions, shared organization and enterprise skills now function in local and agent sessions.

Changes in VS Code 1.139 Release

The VS Code extension (version 1.139) includes updates regarding remote development environments and UI organization.

• Agent Execution in Dev Containers: Agents can now be executed in Dev Containers on SSH, Tunnel, and WSL hosts, enabling the use of remote project tools and dependencies (rolling out gradually).

• Compact View and Session Management: A Compact View to organize busy session lists, a filter to hide empty groups, and the ability to rename sessions and chats directly from the list have been added.

• Chat Layout Selection: Users can now choose between individual chat tabs within a session or a single active chat view without losing conversation history (preview feature).

Usage Precautions and Limitations

• Unverified Elements: All contents described in this article are based on primary sources and constitute a research report [prior to actual device verification]. Actual UI layouts and the rollout status of available features vary depending on the account plan, organization settings, and client version.

• Nature of Preview Features: Public previews and features rolling out gradually (such as agent execution in Dev Containers) are subject to change in specifications without notice.

• Differences by Plan: Access permissions for new models and enterprise management features vary depending on the subscription plan in use (e.g., Pro, Business, Enterprise).

Summary

The key points and constraints reviewed in this article are as follows.

• The latest weekly release added new models such as Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and Grok 4.7.

• The desktop application has introduced access restrictions via a local sandbox and monitoring using OpenTelemetry.

• Practical features have been expanded across Slack/Teams, JetBrains, and VS Code environments, such as model switching, automated approval workflows, and container execution in remote environments.

• Before execution, be sure to verify your current plan, client version, and enterprise policy settings.

References

• GitHub Copilot weekly releases — September 21