VS Code Automation
Automate VS Code (Code OSS) using @playwright/cli. VS Code is built on Electron/Chromium and exposes a Chrome DevTools Protocol (CDP) port that @playwright/cli can attach to, enabling the same snapshot-interact workflow used for web pages.
Prerequisites
@playwright/cliis available via devDependencies. Runnpm installat the repo root, then usenpx @playwright/clito invoke commands. Alternatively, install globally withnpm install -g @playwright/cli.- For Code OSS (VS Code dev build): The repo must be built before launching.
./scripts/code.shruns the build automatically if needed, or setVSCODE_SKIP_PRELAUNCH=1to skip the compile step if you've already built. - CSS selectors are internal implementation details. Selectors like
.interactive-input-part,.interactive-input-editor, and.part.auxiliarybarused inevalcommands are VS Code internals that may change across versions. If they stop working, usenpx @playwright/cli snapshotto re-discover the current DOM structure.
Core Workflow
- Launch Code OSS with remote debugging enabled
- Attach npx @playwright/cli to the CDP port
- Snapshot to discover interactive elements
- Interact using element refs
- Re-snapshot after navigation or state changes
📸 Take screenshots for a paper trail. Usenpx @playwright/cli screenshot --filename=<path>at key moments — after launch, before/after interactions, and when something goes wrong. Screenshots provide visual proof of what the UI looked like and are invaluable for debugging failures or documenting what was accomplished. Save screenshots inside a timestamped subfolder so each run is isolated and nothing gets overwritten: ``bash # Create a timestamped folder for this run's screenshots SCREENSHOT_DIR="/tmp/code-oss-screenshots/$(date +%Y-%m-%dT%H-%M-%S)" mkdir -p "$SCREENSHOT_DIR" # Save a screenshot npx @playwright/cli screenshot --filename="$SCREENSHOT_DIR/after-launch.png"``
# Launch Code OSS with remote debugging
# NOTE: unset ELECTRON_RUN_AS_NODE if running from a Claude Code terminal
unset ELECTRON_RUN_AS_NODE
./scripts/code.sh --remote-debugging-port=9224
# Wait for Code OSS to start, retry until attached
for i in 1 2 3 4 5; do npx @playwright/cli attach --cdp=http://127.0.0.1:9224 2>/dev/null && break || sleep 3; done
# Verify you're connected to the right target (not about:blank)
# If `tab-list` shows the wrong target, run `npx @playwright/cli close` and reattach
npx @playwright/cli tab-list
# Discover UI elements
npx @playwright/cli snapshot
# Focus the chat input (macOS)
npx @playwright/cli press Control+Meta+iAttaching
# Attach to a specific CDP port
npx @playwright/cli attach --cdp=http://127.0.0.1:9222After attach, all subsequent commands target the connected app without needing to reattach.
Tab Management
Electron apps often have multiple windows or webviews. Use tab commands to list and switch between them:
# List all available targets (windows, webviews, etc.)
npx @playwright/cli tab-list
# Switch to a specific tab by index
npx @playwright/cli tab-select 2Launching Code OSS (VS Code Dev Build)
The VS Code repository includes scripts/code.sh which launches Code OSS from source. It passes all arguments through to the Electron binary, so --remote-debugging-port works directly:
cd <repo-root> # the root of your VS Code checkout
./scripts/code.sh --remote-debugging-port=9224Wait for the window to fully initialize, then attach:
# Wait for Code OSS to start, retry until attached
for i in 1 2 3 4 5; do npx @playwright/cli attach --cdp=http://127.0.0.1:9224 2>/dev/null && break || sleep 3; done
# Verify you're connected to the right target (not about:blank)
# If `tab-list` shows the wrong target, run `npx @playwright/cli close` and reattach
npx @playwright/cli tab-list
npx @playwright/cli snapshotTips:
- Unset
ELECTRON_RUN_AS_NODEbefore launching if it's set in your shell (e.g., in Claude Code terminals):unset ELECTRON_RUN_AS_NODE &&./scripts/code.sh --remote-debugging-port=9224 - Set
VSCODE_SKIP_PRELAUNCH=1to skip the compile step if you've already built:VSCODE_SKIP_PRELAUNCH=1./scripts/code.sh --remote-debugging-port=9224(from the repo root) - Code OSS uses the default user data directory. Unlike VS Code Insiders, you don't typically need
--user-data-dirsince there's usually only one Code OSS instance running. - If you see "Sent env to running instance. Terminating..." it means Code OSS is already running and forwarded your args to the existing instance. Quit Code OSS and relaunch with the flag, or use
--user-data-dir=/tmp/code-oss-debugto force a new instance.
Launching the Agents App (Agents Window)
The Agents app is a separate workbench mode launched with the --agents flag. It uses a dedicated user data directory to avoid conflicts with the main Code OSS instance.
cd <repo-root> # the root of your VS Code checkout
./scripts/code.sh --agents --remote-debugging-port=9224Wait for the window to fully initialize, then attach:
# Wait for Agents app to start, retry until attached
for i in 1 2 3 4 5; do npx @playwright/cli attach --cdp=http://127.0.0.1:9224 2>/dev/null && break || sleep 3; done
# Verify you're connected to the right target (not about:blank)
npx @playwright/cli tab-list
npx @playwright/cli snapshotTips:
- The
--agentsflag launches the Agents workbench instead of the standard VS Code workbench. - Set
VSCODE_SKIP_PRELAUNCH=1to skip the compile step if you've already built.
Launching VS Code Extensions for Debugging
To debug a VS Code extension via npx @playwright/cli, launch VS Code Insiders with --extensionDevelopmentPath and --remote-debugging-port. Use --user-data-dir to avoid conflicting with an already-running instance.
# Build the extension first
cd <extension-repo-root> # e.g., the root of your extension checkout
npm run compile
# Launch VS Code Insiders with the extension and CDP
code-insiders \
--extensionDevelopmentPath="<extension-repo-root>" \
--remote-debugging-port=9223 \
--user-data-dir=/tmp/vscode-ext-debug
# Wait for VS Code to start, retry until attached
for i in 1 2 3 4 5; do npx @playwright/cli attach --cdp=http://127.0.0.1:9223 2>/dev/null && break || sleep 3; done
# Verify you're connected to the right target (not about:blank)
# If `tab-list` shows the wrong target, run `npx @playwright/cli close` and reattach
npx @playwright/cli tab-list
npx @playwright/cli snapshotKey flags:
--extensionDevelopmentPath=<path>— loads your extension from source (must be compiled first)--remote-debugging-port=9223— enables CDP (use 9223 to avoid conflicts with other apps on 9222)--user-data-dir=<path>— uses a separate profile so it starts a new process instead of sending to an existing VS Code instance
Without --user-data-dir, VS Code detects the running instance, forwards the args to it, and exits immediately — you'll see "Sent env to running instance. Terminating..." and CDP never starts.
Restarting After Code Changes
After making changes to Code OSS source code, you must restart to pick up the new build. The workbench loads the compiled JavaScript at startup — changes are not hot-reloaded.
Restart Workflow
- Rebuild the changed code
- Kill the running Code OSS instance
- Relaunch with the same flags
# 1. Ensure your build is up to date.
# Normally you can skip a manual step here and let ./scripts/code.sh in step 3
# trigger the build when needed (or run `npm run watch` in another terminal).
# 2. Kill the Code OSS instance listening on the debug port (if running)
pids=$(lsof -t -i :9224)
if [ -n "$pids" ]; then
kill $pids
fi
# 3. Relaunch
./scripts/code.sh --remote-debugging-port=9224
# 4. Reattach npx @playwright/cli
for i in 1 2 3 4 5; do npx @playwright/cli attach --cdp=http://127.0.0.1:9224 2>/dev/null && break || sleep 3; done
npx @playwright/cli tab-list
npx @playwright/cli snapshotTip: If you're iterating frequently, run npm run watch in a separate terminal so compilation happens automatically. You still need to kill and relaunch Code OSS to load the new build.Interacting with Monaco Editor (Chat Input, Code Editors)
VS Code uses Monaco Editor for all text inputs including the Copilot Chat input. Monaco editors require specific npx @playwright/cli techniques — standard click, fill, and type commands may not work depending on the VS Code build.
The Universal Pattern: Focus via Keyboard Shortcut + press
This works on all VS Code builds (Code OSS, Insiders, stable):
# 1. Open and focus the chat input with the keyboard shortcut
# macOS:
npx @playwright/cli press Control+Meta+i
# Linux / Windows:
npx @playwright/cli press Control+Alt+i
# 2. Type using individual press commands
npx @playwright/cli press H
npx @playwright/cli press e
npx @playwright/cli press l
npx @playwright/cli press l
npx @playwright/cli press o
npx @playwright/cli press Space # Use "Space" for spaces
npx @playwright/cli press w
npx @playwright/cli press o
npx @playwright/cli press r
npx @playwright/cli press l
npx @playwright/cli press d
# Verify text appeared (optional)
npx @playwright/cli eval '
(() => {
const sidebar = document.querySelector(".part.auxiliarybar");
const viewLines = sidebar.querySelectorAll(".interactive-input-editor .view-line");
return Array.from(viewLines).map(vl => vl.textContent).join("|");
})()'
# 3. Send the message (same on all platforms)
npx @playwright/cli press EnterChat focus shortcut by platform:
- macOS:
Ctrl+Cmd+I→npx @playwright/cli press Control+Meta+i - Linux:
Ctrl+Alt+I→npx @playwright/cli press Control+Alt+i - Windows:
Ctrl+Alt+I→npx @playwright/cli press Control+Alt+i
This shortcut focuses the chat input and sets document.activeElement to a DIV with class native-edit-context — VS Code's native text editing surface that correctly processes key events from npx @playwright/cli press.
fill <ref> — Works on Some Builds
On VS Code Insiders (extension debug mode), fill handles focus and input in one step:
npx @playwright/cli snapshot
# Look for: textbox "The editor is not accessible..." [ref=e62]
npx @playwright/cli fill e62 "Hello from George!"Tip: If fill silently drops text (the editor stays empty), the ref may be stale or the editor not yet ready. Re-snapshot to get a fresh ref and try again. You can verify text was entered using the snippet in "Verifying Text and Clearing" below.However, fill silently fails on Code OSS — the command completes without error but no text appears. Always verify text appeared after typing, and fall back to the keyboard shortcut + press pattern if it didn't. The press-per-key approach works universally across all builds.
Compatibility Matrix
| Method | VS Code Insiders | Code OSS |
|---|---|---|
press per key (after focus shortcut) | ✅ Works | ✅ Works |
fill <ref> "text" | ✅ Works | ❌ Silent fail |
type "text" (after focus) | ✅ Works | ❌ Silent fail |
click <ref> on editor | ❌ Blocked by overlay | ❌ Blocked by overlay |
Fallback: Focus via JavaScript Mouse Events
If the keyboard shortcut doesn't work (e.g., chat panel isn't configured), you can focus the editor via JavaScript:
npx @playwright/cli eval '
(() => {
const inputPart = document.querySelector(".interactive-input-part");
const editor = inputPart.querySelector(".monaco-editor");
const rect = editor.getBoundingClientRect();
const x = rect.x + rect.width / 2;
const y = rect.y + rect.height / 2;
editor.dispatchEvent(new MouseEvent("mousedown", { bubbles: true, clientX: x, clientY: y }));
editor.dispatchEvent(new MouseEvent("mouseup", { bubbles: true, clientX: x, clientY: y }));
editor.dispatchEvent(new MouseEvent("click", { bubbles: true, clientX: x, clientY: y }));
return "activeElement: " + document.activeElement?.className;
})()'
# Then use press for each character
npx @playwright/cli press H
npx @playwright/cli press e
# ...Verifying Text and Clearing
# Verify text in the chat input
npx @playwright/cli eval '
(() => {
const sidebar = document.querySelector(".part.auxiliarybar");
const viewLines = sidebar.querySelectorAll(".interactive-input-editor .view-line");
return Array.from(viewLines).map(vl => vl.textContent).join("|");
})()'
# Clear the input (Select All + Backspace)
# macOS:
npx @playwright/cli press Meta+a
# Linux / Windows:
npx @playwright/cli press Control+a
# Then delete:
npx @playwright/cli press BackspaceScreenshot Tips for VS Code
On ultrawide monitors, the chat sidebar may be in the far-right corner of the CDP screenshot. Options:
- Use
npx @playwright/cli screenshot --full-pageto capture the entire window - Use element screenshots:
npx @playwright/cli screenshot <ref> --filename=sidebar.png(get the ref from a snapshot) - Maximize the sidebar first: click the "Maximize Secondary Side Bar" button
macOS: Ifnpx @playwright/cli screenshotreturns "Permission denied", your terminal needs Screen Recording permission. Grant it in System Settings → Privacy & Security → Screen Recording. As a fallback, use theevalverification snippet to confirm text was entered — this doesn't require screen permissions.
Troubleshooting
"Connection refused" or "Cannot connect"
- Make sure Code OSS was launched with
--remote-debugging-port=NNNN - If Code OSS was already running, quit and relaunch with the flag
- Check that the port isn't in use by another process:
- macOS / Linux: lsof -i:9224 - Windows: netstat -ano | findstr 9224
Elements not appearing in snapshot
- VS Code uses multiple webviews. Use
npx @playwright/cli tab-listto list targets and switch to the right one withnpx @playwright/cli tab-select <index>
Cannot type in Monaco Editor inputs
- Use
npx @playwright/cli pressfor individual keystrokes after focusing the input. Focus the chat input with the keyboard shortcut (macOS:Ctrl+Cmd+I, Linux/Windows:Ctrl+Alt+I). fillandtypework on VS Code Insiders but silently fail on Code OSS — they complete without error but no text appears. Thepress-per-key approach works universally.- See the "Interacting with Monaco Editor" section above for the full compatibility matrix.
Cleanup
Always kill the Code OSS instance when you're done. Code OSS is a full Electron app that consumes significant memory (often 1–4 GB+). Leaving it running wastes resources and holds the CDP port.
# Disconnect npx @playwright/cli
npx @playwright/cli close
# Kill the Code OSS instance listening on the debug port (if running)
# macOS / Linux:
pids=$(lsof -t -i :9224)
if [ -n "$pids" ]; then
kill $pids
fi
# Windows:
# taskkill /F /PID <PID>
# Or use Task Manager to end "Code - OSS"Verify it's gone:
# Confirm no process is listening on the debug port
lsof -i :9224 # should return nothing