Josh Spicer

This commit **implements and refines** the `ChatSessionCustomizationProvider` for **Claude and Copilot CLI chat sessions**, enabling the dynamic discovery and listing of **agents, instructions, skills, and hooks**. For Claude, this involves a new `IClaudeRuntimeDataService` to cache SDK agents, and discovery of instructions, skills, and hooks from `.claude/` directories and settings files. The Copilot CLI provider now leverages `ICopilotCLIAgents` and expands path filtering to include `.github/`, `.copilot/`, and `.agents/` in both workspace and user home directories. This **new capability** significantly enhances the customizability of chat interactions by providing relevant context and tools, backed by extensive unit tests and synchronization with the latest VS Code API.

This commit **enhances the editor's whitespace rendering controls** by introducing a new submenu, providing users with more granular options beyond a simple toggle. It **refactors the `toggleRenderWhitespace` command** to offer specific modes like `all`, `boundary`, or `none` for displaying whitespace, improving the user experience for managing code readability. This **feature enhancement** impacts the **editor's context menu and command palette**, making whitespace settings more intuitive. Additionally, it **refactors the menu registration logic** by consolidating submenu registration into `Action2` properties and removing redundant `MenuRegistry` calls, improving code maintainability.

This commit introduces a **new built-in skill** named `sync-upstream` to the **sessions** module, enhancing branch management capabilities. This **new capability** allows users to rebase their session branches against an upstream branch, simplifying the process of keeping development environments current. The change includes comprehensive documentation in `src/vs/sessions/skills/sync-upstream/SKILL.md`, detailing the skill's purpose, workflow, and conflict resolution strategies. This improves the overall user experience by providing a streamlined method for maintaining up-to-date session branches.

This commit delivers crucial **fixes** and **enhancements** to the **Chat feature's AI customization providers**. It **resolves issues** with external customization harness deduplication and refines the active harness fallback behavior upon disposal within the `customizationHarnessService`. Furthermore, it **refactors** the instruction item processing by extracting shared classification and grouping logic into `buildInstructionListItem`, which now correctly identifies and groups agent-specific instruction files (e.g., `AGENTS.md`) under a dedicated header in the **AI customization list widget**. This work ensures more reliable management of custom chat behaviors and improves the organization and clarity of available chat customization options for users.

This commit introduces significant **enhancements to AI chat customizations**, enabling external providers to define **grouping and badges** for their customization items. The `AICustomizationListWidget` is updated to render these new visual cues, improving the organization and clarity of customization options. Additionally, the commit refines the logic for **inferring storage locations from URIs** for these items and includes performance optimizations for `groupKey` lookups. This work primarily constitutes a **feature enhancement**, expanding the **Chat Session Customization API** to allow external providers to offer richer customization options. Ultimately, this improves the user experience for managing chat sessions by providing better organization and visual cues.

This commit performs a **refactoring** to streamline the **dependency injection (DI)** of core services within the **`PromptsService`** for the **Chat feature**. It updates `src/vs/sessions/contrib/chat/browser/promptsService.ts` to directly use injected `fileService` and `pathService` instances within methods like `getCopilotRoot` and `discoverBuiltinSkills`, moving away from indirect access. Concurrently, the access modifiers for `fileService` and `pathService` in `src/vs/workbench/contrib/chat/common/promptSyntax/service/promptsServiceImpl.ts` are changed from private to protected, enabling subclasses to properly access these services. This change significantly improves the **maintainability and extensibility** of the prompt handling logic by enforcing a more robust service consumption pattern.

This commit **overhauls the AI chat customization system** by replacing the internal `chatSessionCustomizations` API with a **new, proposed `chatSessionCustomizationProvider` extension API**. This **refactoring** enables extensions to **register as providers for AI chat customization items**, shifting discovery and management from a core-driven, group-based model to an **extension-driven, flat item model**. The **Chat AI Customization UI** (management editor, list widget, debug panel) is updated to dynamically integrate these external providers, including new menu contribution points for create actions and a kill-switch for the API. This significantly **enhances the extensibility of AI chat features**, allowing extensions to contribute their own agents and skills.

This commit **refactors** the **Sessions** module by converting all built-in prompts into a standardized **skill** format, moving them to `vs/sessions/skills/{name}/SKILL.md` and removing the legacy prompt discovery system. It introduces a **new capability** to display a 'UI Integration' badge in the **AI Customizations editor** for skills that drive UI surfaces, such as `act-on-feedback` and `generate-run-commands`, and also for Git-related skills like `create-pr` and `commit` that are triggered from the Changes toolbar. This change streamlines the management of AI capabilities, provides clearer visibility into skill integrations for users, and updates the `IAICustomizationWorkspaceService` interface with `getSkillUIIntegrations()` to support this new UI mapping. The architecture is simplified, focusing prompt listing exclusively on skills, and relevant documentation in `AI_CUSTOMIZATIONS.md` is updated.

This commit significantly enhances the **AI Customization Management Editor** by implementing **dirty state tracking and explicit save handling**. It ensures that the editor accurately reflects unsaved changes, prompting users to save their modifications and preventing accidental data loss within the **AI Customization management feature**. The work involves refactoring confirmation logic into a robust save mechanism, where only explicit user actions trigger the save flow, while auto-saves are guarded. This **new capability** improves user experience and data integrity, with a minor adjustment to dialog escape key behavior to prevent unintended closures.

This commit introduces a **new extensibility API** for **Chat Session Customizations**, enabling extensions to contribute custom chat session behaviors and UI elements. It establishes the `ChatSessionCustomizationsProvider` API, including new types and a registration mechanism (`chat.registerChatSessionCustomizationsProvider`), and implements the full end-to-end plumbing across the **Extension Host, Main Thread, and Chat Sessions Service**. Core **Chat UI components** such as the `AICustomizationListWidget`, `chatInputPart`, and session pickers are **refactored** to dynamically support these extension-contributed session types, moving away from hardcoded built-in providers. This significant **grow** work provides a flexible and extensible chat experience, allowing extensions to define custom commands and items within the chat customization UI, all controlled by the `chat.customizations.providerApi.enabled` setting.

This commit delivers a series of **bug fixes** and **UI improvements** aimed at enhancing the **AI Customization Management Editor** and the overall agentic engineering development loop. It resolves inconsistencies in displaying **custom agent names** and refines **tooltips** to show workspace-relative paths, extension names, or "Built-in" labels for clarity. Significant effort was also dedicated to **stabilizing list layout** within the editor, addressing issues like footer overlap and ensuring correct rendering during visibility transitions, alongside a fix to correctly show **user-scoped hooks** in the sessions window. These changes collectively improve the editor's reliability, user experience, and consistency.

This commit performs a **maintenance update** by bumping the `vscode-distro` dependency to a specific upstream commit, `6c98cfe8`. This action ensures the project is aligned with the latest changes from the core VS Code distribution, incorporating any recent fixes, improvements, or foundational updates. The update broadly affects the **entire application's underlying distribution**, ensuring the project remains current with its upstream base.

This commit **fixes a UI clipping issue** within the **chat customization MCP and plugin widgets**. The problem occurred when **toggling browse mode**, as the list layout failed to re-adjust for the appearing/disappearing back link, now resolved by **re-layouting the list** to account for UI chrome changes. Additionally, it **updates AI customization component fixtures** by registering required services like `IProductService` and `IDialogService`, which resolves previous test failures and expands test coverage for various UI states. The commit also incorporates PR review feedback, removing manual `layout()` calls in fixtures, and updates the `SKILL.md` documentation.

This commit provides a **bug fix** for issues affecting the **AI Customization list widgets** within the **Chat workbench contribution**. It resolves problems with the **rendering, updating, and lifecycle management** of items in various specialized lists, such as `pluginListWidget` and `mcpListWidget`, by adjusting methods like `renderPluginItem`, `updateElements`, and `createListItem`. This ensures a more stable and correct display of AI customization options for users, with new tests added to prevent regressions in the `aiCustomizationListWidget`.

This commit **enhances the Chat UI** by **reconfiguring the gear menu** to provide direct access to the **AI Customizations editor**. The gear icon now immediately opens the editor when `chat.customizationsMenu.enabled` is true, while actions such as `Configure Tool Sets` and `Show Agent Debug Logs` are relocated to a secondary context menu. This **UI/UX improvement** streamlines the customization workflow, making key settings more accessible within the **Chat** experience. The original gear dropdown behavior is preserved if the setting is disabled, ensuring backward compatibility and flexibility for users.

This commit **fixes a visual bug** within the **sessions welcome overlay** by preventing it from flashing during transient entitlement state changes. It **refactors** the `SessionsWelcomeContribution` to enhance **entitlement state monitoring**, introducing a mechanism to delay overlay display and improve responsiveness. This ensures a smoother and less distracting **user experience** when first interacting with the sessions feature, especially on initial launch or during entitlement updates. New tests in `welcome.contribution.test.ts` validate the overlay's visibility behavior under various entitlement conditions.

This commit **enhances the AI Customization management UI** by introducing an **inline badge** to list items. This **feature improvement** visually separates context instructions, such as `applyTo` patterns (e.g., `**/*.ts` or 'always added'), from the item's display name, making the interface cleaner and more informative. The badge includes a **hover tooltip** for detailed explanations and its text is now **searchable** within the list. This **enhancement** also involves **refactoring** to extract shared `.inline-badge` CSS for consistent styling across the application and updates the `IAICustomizationListItem` interface to support generic badge and tooltip fields for future extensibility.

This commit introduces a **UI enhancement** to the **Chat Customizations editor**, specifically within the **AI customization list widget**. Items contributed by the **default chat extension**, such as agents, skills, prompts, and instructions, are now logically grouped under a new **'Built-in' header** instead of the generic 'Extensions' category. This change improves the **organization and clarity** for users by distinguishing core functionalities, achieved by identifying the default chat extension via `IProductService` and setting a `groupKey` at the UI layer. It also involves **refactoring** by moving `BUILTIN_STORAGE` and related types to a common layer, adding new tests, and updating the `AI_CUSTOMIZATIONS.md` specification.

This commit **corrects the display categorization** of **MCP servers** within the **AI Customization** feature of the Chat workbench. Previously, servers originating from the `github.copilot` and `github.copilot-chat` extensions were erroneously listed under the "Extensions" group. This **bug fix** updates the server categorization logic in `src/vs/workbench/contrib/chat/browser/aiCustomization/mcpListWidget.ts` to treat these specific Copilot servers as **built-in**. The change introduces an `isCopilotExtension` helper function to facilitate this distinction, resulting in a more accurate and intuitive **AI server management UI** for users.

This commit focuses on **developer experience improvements** and **internal tooling** for the **AI chat customizations** feature. It introduces and refines **component fixtures** for the `aiCustomizationListWidget` and the `aiCustomizationManagementEditor`, facilitating easier development and testing of these UI components. Additionally, it includes a **bug fix** for DOM element creation within the `aiCustomizationManagementEditor.ts` to use shorthand syntax, and updates the related **AI customizations specification** in `AI_CUSTOMIZATIONS.md` and a **developer skill definition**. This work enhances the internal development workflow and ensures consistency in the chat customization management UI.