What problem does it solve? Developers working on the Agents window (src/vs/sessions/) need to respect strict layering rules, fixed layout constraints, custom menu IDs, and spec documents that must stay in sync with code. This Skill provides the architectural map and development guidelines so changes land in the right place without violating dependency rules. ## Core Features & Use Cases - Layering and dependency rules: Enforces that vs/sessions may import from vs/workbench and below, but never the reverse, validated with npm run valid-layers-check. - Architecture reference: Documents the folder structure, fixed layout parts (Titlebar, Sidebar, Chat Bar, Auxiliary Bar, Panel, modal editors), the AgentSessionsChatWidget wrapper with deferred session creation, custom Menus.* IDs, and context keys. - Development workflows: Covers how to add contributions under contrib/<feature>/browser/, register entry points, override services, and validate changes with npm run compile-check-ts-native and unit tests. - Use Case: When adding a new sidebar view to the Agents window, follow the guidelines to place it in contrib/, register it with WindowVisibility.Sessions, use Menus.SidebarTitle instead of shared MenuId.*, and update LAYOUT.md with a Revision History entry. ## Quick Start Ask the agent to implement a new feature or fix a bug in the Agents window under src/vs/sessions while following the sessions architecture guidelines.