Visual Studio Code is built with a layered architecture using TypeScript, web APIs and Electron, combining web technologies with native app capabilities. The codebase is organized into key architectural layers: The core architecture follows these principles: - Layered architecture - from base, platform, editor, to workbench - Dependency injection - Services are injected through constructor parameters - If non-service parameters are needed, they need to come before the service parameters - Contribution model - Features contribute to registries and extension…
Primary accessibility skill for VS Code. REQUIRED for new feature and contribution work, and also applies to updates of existing UI. Covers accessibility help dialogs, accessible views, verbosity settings, signals, ARIA announcements, keyboard navigation, and ARIA labels/roles.
Build and review cross-cutting agent-host chat behavior through lifecycle contributions. Use when adding turn lifecycle side effects, prompt or context injection, restored-history transformation, protocol-action observation, or when reviewing changes that add code to AgentSideEffects or AgentService.
Analyze Agent Host debug log exports. Use when given an ah-logs or ahp-logs zip/folder, an Export Agent Host Debug Logs bundle, events.jsonl, AHP JSONL transport logs, Agent Host.log, remote-agenthost.log, or copilot-logs.
Identify all files a specific author contributed to on a branch vs its upstream, tracing code through renames. Use when asked who edited what, what code an author contributed, or to audit authorship before a merge. This skill should be run as a subagent — it performs many git operations and returns a concise table.
Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
Find and read timestamped process logs from Code OSS dev builds, including main.log, renderer.log, extension host logs, and agenthost.log. For bundles produced by Export Agent Host Debug Logs, use agent-host-logs.
Review code changes for correctness, regressions, and unintended scope. Use when reviewing a pull request, branch, commit, patch, or local diff, including when invoked with /code-review.
Use when creating or updating component fixtures for screenshot testing, or when designing UI components to be fixture-friendly. Covers fixture file structure, theming, service setup, CSS scoping, async rendering, and common pitfalls.
The VS Code design philosophy — a shared Values→Principles→Moves vocabulary for reasoning about UI in design terms instead of raw pixels. Use when designing, building, reviewing, or giving feedback on any visual surface; when deciding a radius, spacing, type role, icon size, border, color, or motion; or when translating a "this feels off" observation into a concrete, principled fix.
Use when adding, changing, or reviewing a VS Code A/B experiment, either an experiment-controlled setting or a treatment read with the assignment service, and when deciding whether and where to log an `experimentTrigger` event for a triggered ExP scorecard.
Use when adding, reviewing, or troubleshooting an interactive release-note Try This experience, including commands, views, editor samples, Chat drafts, guided spotlights, prerequisites, scoped targets, or Agents-window handoff.
Plain text files in a repository that tell a coding agent how the project works: commands to run, conventions to follow and things to avoid. CLAUDE.md, AGENTS.md, cursor rules and skills are the common kinds.
CLAUDE.md or AGENTS.md?
CLAUDE.md is read by Claude Code. AGENTS.md is an open format that Codex, Cursor and other agents read. Many projects keep one and point the other at it.
What is a skill?
A folder with a SKILL.md that describes one capability, such as filling PDFs or reviewing code. The agent loads it only when the task calls for it.
Can I search my own team's files too?
Your agents already can, over MCP, limited to the files you're allowed to read. Searching them from this page is coming.
MicrosoftCopilot instructions