Awesome-omni-skill sessions

Agent Sessions window architecture — covers the sessions-first app, layering, folder structure, chat widget, menus, contributions, entry points, and development guidelines. Use when implementing features or fixing issues in the Agent Sessions window.

install

source · Clone the upstream repo

git clone https://github.com/diegosouzapw/awesome-omni-skill

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/diegosouzapw/awesome-omni-skill "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/development/sessions" ~/.claude/skills/diegosouzapw-awesome-omni-skill-sessions && rm -rf "$T"

manifest: skills/development/sessions/SKILL.md

source content

When working on the Agent Sessions window (

src/vs/sessions/

), always follow these guidelines:

1. Read the Specification Documents First

The

src/vs/sessions/

directory contains authoritative specification documents. Always read the relevant spec before making changes.

Document	Path	Covers
Layer spec	`src/vs/sessions/README.md`	Layering rules, dependency constraints, folder conventions
Layout spec	`src/vs/sessions/LAYOUT.md`	Grid structure, part positions, sizing, CSS classes, API reference
AI Customizations	`src/vs/sessions/AI_CUSTOMIZATIONS.md`	AI customization editor and tree view design
Chat Widget	`src/vs/sessions/browser/widget/AGENTS_CHAT_WIDGET.md`	Chat widget wrapper architecture, deferred session creation, option delivery
AI Customization Mgmt	`src/vs/sessions/contrib/aiCustomizationManagement/browser/SPEC.md`	Management editor specification
AI Customization Tree	`src/vs/sessions/contrib/aiCustomizationTreeView/browser/SPEC.md`	Tree view specification

If you modify the implementation, you must update the corresponding spec to keep it in sync. Update the Revision History table at the bottom of

LAYOUT.md

with a dated entry.

2. Architecture Overview

2.1 Layering

vs/base          ← Foundation utilities
vs/platform      ← Platform services
vs/editor        ← Text editor core
vs/workbench     ← Standard VS Code workbench
vs/sessions      ← Agent Sessions window (this layer)

Key constraint:

vs/sessions

may import from

vs/workbench

and all layers below it.

vs/workbench

must never import from

vs/sessions

2.2 Dependency Rules

✅ Import from
```
vs/base
```
,
```
vs/platform
```
,
```
vs/editor
```
,
```
vs/workbench
```
✅ Import within
```
vs/sessions
```
(internal)
❌ Never import
```
vs/sessions
```
from
```
vs/workbench
```
Run
```
npm run valid-layers-check
```
to verify layering

2.3 How It Differs from VS Code

Aspect	VS Code Workbench	Agent Sessions Window
Layout	Configurable part positions	Fixed layout, no settings customization
Chrome	Activity bar, status bar, banner	Simplified — none of these
Primary UX	Editor-centric	Chat-first (Chat Bar is a primary part)
Editors	In the grid layout	Modal overlay above the workbench
Titlebar	Menubar, editor actions, layout controls	Session picker, run script, toggle sidebar/panel
Navigation	Activity bar with viewlets	Sidebar (views) + sidebar footer (account)
Entry point	`vs/workbench` workbench class	`vs/sessions/browser/workbench.ts` `Workbench` class

3. Folder Structure

src/vs/sessions/
├── README.md                               # Layer specification (read first)
├── LAYOUT.md                               # Authoritative layout specification
├── AI_CUSTOMIZATIONS.md                    # AI customization design document
├── sessions.common.main.ts                 # Common (browser + desktop) entry point
├── sessions.desktop.main.ts                # Desktop entry point (imports all contributions)
├── common/                                 # Shared types and context keys
│   └── contextkeys.ts                      # ChatBar context keys
├── browser/                                # Core workbench implementation
│   ├── workbench.ts                        # Main Workbench class (implements IWorkbenchLayoutService)
│   ├── menus.ts                            # Agent sessions menu IDs (Menus export)
│   ├── layoutActions.ts                    # Layout toggle actions (sidebar, panel, auxiliary bar)
│   ├── paneCompositePartService.ts         # AgenticPaneCompositePartService
│   ├── style.css                           # Layout-specific styles
│   ├── widget/                             # Agent sessions chat widget
│   │   ├── AGENTS_CHAT_WIDGET.md           # Chat widget architecture doc
│   │   ├── agentSessionsChatWidget.ts      # Main wrapper around ChatWidget
│   │   ├── agentSessionsChatTargetConfig.ts # Observable target state
│   │   ├── agentSessionsTargetPickerActionItem.ts # Target picker for input toolbar
│   │   └── media/
│   └── parts/                              # Workbench part implementations
│       ├── parts.ts                        # AgenticParts enum
│       ├── titlebarPart.ts                 # Titlebar (3-section toolbar layout)
│       ├── sidebarPart.ts                  # Sidebar (with footer for account widget)
│       ├── chatBarPart.ts                  # Chat Bar (primary chat surface)
│       ├── auxiliaryBarPart.ts             # Auxiliary Bar (with run script dropdown)
│       ├── panelPart.ts                    # Panel (terminal, output, etc.)
│       ├── projectBarPart.ts              # Project bar (folder entries)
│       ├── agentSessionsChatInputPart.ts   # Chat input part adapter
│       ├── agentSessionsChatWelcomePart.ts # Welcome view (mascot + target buttons + pickers)
│       └── media/                          # Part CSS files
├── electron-browser/                       # Desktop-specific entry points
│   ├── sessions.main.ts                    # Desktop main bootstrap
│   ├── sessions.ts                         # Electron process entry
│   ├── sessions.html                       # Production HTML shell
│   └── sessions-dev.html                   # Development HTML shell
└── contrib/                                # Feature contributions
    ├── accountMenu/browser/                # Account widget for sidebar footer
    ├── aiCustomizationManagement/browser/  # AI customization management editor
    ├── aiCustomizationTreeView/browser/    # AI customization tree view sidebar
    ├── changesView/browser/                # File changes view
    ├── chat/browser/                       # Chat actions (run script, branch, prompts)
    ├── configuration/browser/              # Configuration overrides
    └── sessions/browser/                   # Sessions view, title bar widget, active session service

4. Layout

Use the

agent-sessions-layout

skill for detailed guidance on the layout. Key points:

4.1 Visual Layout

┌─────────┬───────────────────────────────────────────────────────┐
│         │                    Titlebar                           │
│         ├────────────────────────────────────┬──────────────────┤
│ Sidebar │              Chat Bar              │  Auxiliary Bar   │
│         ├────────────────────────────────────┴──────────────────┤
│         │                      Panel                            │
└─────────┴───────────────────────────────────────────────────────┘

Sidebar spans full window height (root grid level)
Titlebar is inside the right section
Chat Bar is the primary interaction surface
Panel is hidden by default (terminal, output, etc.)
Editor appears as a modal overlay, not in the grid

4.2 Parts

Part	Default Visibility	Notes
Titlebar	Always visible	3-section toolbar (left/center/right)
Sidebar	Visible	Sessions view, AI customization tree
Chat Bar	Visible	Primary chat widget
Auxiliary Bar	Visible	Changes view, etc.
Panel	Hidden	Terminal, output
Editor	Hidden	Main part hidden; editors open via `MODAL_GROUP` into `ModalEditorPart`

Not included: Activity Bar, Status Bar, Banner.

4.3 Editor Modal

The main editor part is hidden (

display:none

). All editors open via

MODAL_GROUP

into the standard

ModalEditorPart

overlay (created on-demand by

EditorParts.createModalEditorPart

). The sessions configuration sets

workbench.editor.useModal

'all'

, which causes

findGroup()

to redirect all editor opens to the modal. Click backdrop or press Escape to dismiss.

5. Chat Widget

The Agent Sessions chat experience is built around

AgentSessionsChatWidget

— a wrapper around the core

ChatWidget

that adds:

Deferred session creation — the UI is interactive before any session resource exists; sessions are created on first message send
Target configuration — observable state tracking which agent provider (Local, Cloud) is selected
Welcome view — branded empty state with mascot, target buttons, option pickers, and input slot
Initial session options — option selections travel atomically with the first request
Configurable picker placement — pickers can appear in welcome view, input toolbar, or both

Read

browser/widget/AGENTS_CHAT_WIDGET.md

for the full architecture.

Key classes:

AgentSessionsChatWidget

(

browser/widget/agentSessionsChatWidget.ts

) — main wrapper

AgentSessionsChatTargetConfig

(

browser/widget/agentSessionsChatTargetConfig.ts

) — reactive target state

AgentSessionsChatWelcomePart

(

browser/parts/agentSessionsChatWelcomePart.ts

) — welcome view

AgentSessionsChatInputPart

(

browser/parts/agentSessionsChatInputPart.ts

) — standalone input adapter

6. Menus

The agent sessions window uses its own menu IDs defined in

browser/menus.ts

via the

Menus

export. Never use shared
MenuId.*
constants from

vs/platform/actions

for agent sessions UI — use the

Menus.*

equivalents instead.

Menu ID	Purpose
`Menus.TitleBarLeft`	Left toolbar (toggle sidebar)
`Menus.TitleBarCenter`	Not used directly (see CommandCenter)
`Menus.TitleBarRight`	Right toolbar (run script, open, toggle auxiliary bar)
`Menus.CommandCenter`	Center toolbar with session picker widget
`Menus.TitleBarControlMenu`	Submenu intercepted to render `SessionsTitleBarWidget`
`Menus.PanelTitle`	Panel title bar actions
`Menus.SidebarTitle`	Sidebar title bar actions
`Menus.SidebarFooter`	Sidebar footer (account widget)
`Menus.AuxiliaryBarTitle`	Auxiliary bar title actions
`Menus.AuxiliaryBarTitleLeft`	Auxiliary bar left title actions
`Menus.OpenSubMenu`	"Open..." split button (Open Terminal, Open in VS Code)
`Menus.ChatBarTitle`	Chat bar title actions

7. Context Keys

Defined in

common/contextkeys.ts

Context Key	Type	Purpose
`activeChatBar`	`string`	ID of the active chat bar panel
`chatBarFocus`	`boolean`	Whether chat bar has keyboard focus
`chatBarVisible`	`boolean`	Whether chat bar is visible

8. Contributions

Feature contributions live under

contrib/<featureName>/browser/

and are registered via imports in

sessions.desktop.main.ts

(desktop) or

sessions.common.main.ts

(browser-compatible).

8.1 Key Contributions

Contribution	Location	Purpose
Sessions View	`contrib/sessions/browser/`	Sessions list in sidebar, session picker, active session service
Title Bar Widget	`contrib/sessions/browser/sessionsTitleBarWidget.ts`	Session picker in titlebar center
Account Widget	`contrib/accountMenu/browser/`	Account button in sidebar footer
Run Script	`contrib/chat/browser/runScriptAction.ts`	Run configured script in terminal
Branch Chat Session	`contrib/chat/browser/branchChatSessionAction.ts`	Branch a chat session
Open in VS Code / Terminal	`contrib/chat/browser/chat.contribution.ts`	Open worktree in VS Code or terminal
Prompts Service	`contrib/chat/browser/promptsService.ts`	Agentic prompts service override
Changes View	`contrib/changesView/browser/`	File changes in auxiliary bar
AI Customization Editor	`contrib/aiCustomizationManagement/browser/`	Management editor for prompts, hooks, MCP, etc.
AI Customization Tree	`contrib/aiCustomizationTreeView/browser/`	Sidebar tree for AI customizations
Configuration	`contrib/configuration/browser/`	Configuration overrides

8.2 Service Overrides

The agent sessions window registers its own implementations for:

IPaneCompositePartService

→

AgenticPaneCompositePartService

(creates agent-specific parts)

```
IPromptsService
```
→
```
AgenticPromptsService
```
(scopes prompt discovery to active session worktree)

IActiveSessionService

→

ActiveSessionService

(tracks active session)

8.3

WindowVisibility.Sessions

Views and contributions that should only appear in the agent sessions window (not in regular VS Code) use

WindowVisibility.Sessions

in their registration.

9. Entry Points

File	Purpose
`sessions.common.main.ts`	Common entry — imports browser-compatible services, workbench contributions
`sessions.desktop.main.ts`	Desktop entry — imports desktop services, electron contributions, all `contrib/` modules
`electron-browser/sessions.main.ts`	Desktop bootstrap
`electron-browser/sessions.ts`	Electron process entry
`electron-browser/sessions.html`	Production HTML shell
`electron-browser/sessions-dev.html`	Development HTML shell

10. Development Guidelines

10.1 Adding New Features

Core workbench code (layout, parts, services) →
```
browser/
```
Feature contributions (views, actions, editors) →
```
contrib/<featureName>/browser/
```
Register by importing in
```
sessions.desktop.main.ts
```
(or
```
sessions.common.main.ts
```
for browser-compatible)
Use
```
Menus.*
```
from
```
browser/menus.ts
```
for menu registrations — never shared
```
MenuId.*
```

Use separate storage keys prefixed with

workbench.agentsession.*

workbench.chatbar.*

Use agent session part classes, not standard workbench parts
Mark views with
```
WindowVisibility.Sessions
```
so they only appear in this window

10.2 Layout Changes

Read
LAYOUT.md
first — it's the authoritative spec
Use the
```
agent-sessions-layout
```
skill for detailed implementation guidance
Maintain fixed positions — no settings-based customization
Update
```
LAYOUT.md
```
and its Revision History after any changes
Preserve no-op methods for unsupported features (zen mode, centered layout, etc.)
Handle pane composite lifecycle when hiding/showing parts

10.3 Chat Widget Changes

Read
browser/widget/AGENTS_CHAT_WIDGET.md
first
Prefer composition over modifying core
```
ChatWidget
```
— add behavior in the wrapper
Use
```
IAgentChatTargetConfig
```
observable for target state, not direct session creation
Ensure
```
initialSessionOptions
```
travel atomically with the first request
Test both first-load (extension not yet activated) and new-session flows

10.4 AI Customization Changes

Read
AI_CUSTOMIZATIONS.md
first — it covers the management editor and tree view design
Lean on existing VS Code services (
```
IPromptsService
```
,
```
IMcpService
```
,
```
IChatService
```
)
Browser compatibility required — no Node.js APIs
Active worktree comes from
```
IActiveSessionService
```

10.5 Validation

Check
```
VS Code - Build
```
task output for compilation errors before declaring work complete
Run
```
npm run valid-layers-check
```
for layering violations
Verify part visibility toggling (show/hide/maximize)
Test editor modal open/close behavior
Test sidebar footer renders with account widget