Add 'Open in Agents' action and titlebar widget enhancements

[mrleemurray]

This pull request introduces the "Open in Agents" button to the VS Code title bar, allowing users to quickly launch the Agents application for their current workspace. The implementation includes a new titlebar widget, action, configuration setting, and supporting styles, as well as infrastructure changes to support custom titlebar actions. The changes are organized into two main themes: feature implementation and titlebar infrastructure enhancements.

Screen.Recording.2026-04-23.at.11.43.28.mov

Feature: "Open in Agents" Button

• Added a new Open in Agents titlebar widget, rendered as an icon-only button that expands on hover/focus, with custom styling and accessibility support. The widget launches the Agents app as a sibling application if available, or opens a new in-process window otherwise. [1] [2]
• Registered the action in the title bar's leading group, made it toggleable via the layout customization menu and a new configuration setting (workbench.openInAgents.enabled), and included telemetry for usage tracking.

Titlebar Infrastructure Enhancements

• Introduced TitleBarLeadingActionsGroup to allow certain actions (like "Open in Agents") to appear before layout controls in the title bar, and updated the action filling logic to support this group. [1] [2] [3]
• Updated the titlebar part to support custom view items registered via IActionViewItemService, enabling injection of custom widgets like the new "Open in Agents" button.
• Modified constructors and imports throughout the titlebar implementation to wire up IActionViewItemService as a dependency, ensuring custom action view items can be provided. [1] [2] [3] [4] [5] [6]

These changes collectively enable a more flexible and extensible title bar, while providing users with a convenient entry point to the Agents application.

[Copilot]

Pull request overview

Adds a new “Open in Agents” command surfaced in the desktop titlebar, plus plumbing to support custom titlebar action rendering and a new leading actions group (before layout controls).

Changes:

• Introduces workbench.action.openInAgents, a titlebar widget renderer, telemetry, and a backing configuration toggle.
• Extends titlebar action rendering to support a “leading” group and custom IActionViewItemService-provided view items.
• Wires IActionViewItemService through browser + native titlebar parts and adds widget styling via a new CSS file.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/vs/workbench/electron-browser/parts/titlebar/titlebarPart.ts	Passes IActionViewItemService through native titlebar part constructors.
src/vs/workbench/electron-browser/desktop.contribution.ts	Ensures the new action module is loaded on desktop.
src/vs/workbench/electron-browser/actions/openInAgentsAction.ts	Adds the action, titlebar widget, telemetry, toggle action, and configuration registration.
src/vs/workbench/electron-browser/actions/media/openInAgents.css	Provides styling for the titlebar widget (icon, hover/focus, quality tinting).
src/vs/workbench/browser/parts/titlebar/titlebarPart.ts	Adds IActionViewItemService support + renders a new leading TitleBar group before layout controls.
src/vs/workbench/browser/parts/titlebar/titlebarActions.ts	Defines TitleBarLeadingActionsGroup for “before layout controls” actions.