SyntaxError: browserType.launchPersistentContext: Invalid URL: undefined

[snailmiss]

When I use my local chrome, it got an error.

[snailmiss]

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": [
        "@playwright/mcp@latest",
        "--user-data-dir=/Users/Userxxx/Library/Application Support/Google/Chrome",
        "--executable-path=/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"
      ],
      "url": "http://localhost:8931/sse",
      "autoApprove": [
        "browser_close",
        "browser_wait",
        "browser_resize",
        "browser_console_messages",
        "browser_handle_dialog",
        "browser_file_upload",
        "browser_press_key",
        "browser_navigate_back",
        "browser_navigate_forward",
        "browser_network_requests",
        "browser_pdf_save",
        "browser_snapshot",
        "browser_drag",
        "browser_click",
        "browser_hover",
        "browser_type",
        "browser_select_option",
        "browser_take_screenshot",
        "browser_tab_list",
        "browser_tab_new",
        "browser_tab_select",
        "browser_tab_close",
        "browser_navigate",
        "browser_generate_playwright_test"
      ],
      "disabled": false
    }
  }
}

[mxschmitt]

Do you have Chrome still open? I think that might be caused by: https://developer.chrome.com/blog/remote-debugging-port

Could you try using a different user-data-dir like or leaving this parameter out?

[snailmiss]

Do you have Chrome still open? I think that might be caused by: https://developer.chrome.com/blog/remote-debugging-port

Could you try using a different user-data-dir like or leaving this parameter out?

My Chrome still open,i want to use normal chrome use data dir,expecially the Cookies ,so I set the parameter user-data-dir.When I move this parameter ,It can execute normally.

[pavelfeldman]

Google Chrome introduced a hard ban on automation with the default user profile: https://developer.chrome.com/blog/remote-debugging-port

[mxschmitt]

I can reproduce, working on having a better error. The issue is that the MCP server is launched multiple times which isn't supported as of today. As a workaround you can pass a different userDataDir.

[Mwalek]

Thanks @mxschmitt, it works when I close all Chrome windows and start again.

[clharman]

I get this (or a similar) issue frequently, after periods of inactivity (>15min?) when using the MCP with Cursor. Latest version (0.27), Chrome. Error message below, and it opens a browser with blank URL. The problem goes away when I click the "Refresh" button in Cursor's MCP settings area, even though the status light was already green.

I've also tried closing all of Playwright's tabs and windows, and rerunning the npx command (npx @playwright/mcp@lates) in terminal - nothing helps except Cursor MCP refresh. It doesn't seem to mind if I have several of the npx commands running in terminal either, just that I've refreshed it. Don't know if it's a Playwright, issue, a Playwright MCP issue, a Cursor issue, or what!

SyntaxError: browserType.launchPersistentContext: Invalid URL: undefined
Call log:
  - <launching> /Applications/Google Chrome.app/Contents/MacOS/Google Chrome --disable-field-trial-config --disable-background-networking --disable-background-timer-throttling --disable-backgrounding-occluded-windows --disable-back-forward-cache --disable-breakpad --disable-client-side-phishing-detection --disable-component-extensions-with-background-pages --disable-component-update --no-default-browser-check --disable-default-apps --disable-dev-shm-usage --disable-extensions --disable-features=AcceptCHFrame,AutoExpandDetailsElement,AvoidUnnecessaryBeforeUnloadCheckSync,CertificateTransparencyComponentUpdater,DestroyProfileOnBrowserClose,DialMediaRouteProvider,ExtensionManifestV2Disabled,GlobalMediaControls,HttpsUpgrades,ImprovedCookieControls,LazyFrameLoading,LensOverlay,MediaRouter,PaintHolding,ThirdPartyStoragePartitioning,Translate,AutomationControlled --allow-pre-commit-input --disable-hang-monitor --disable-ipc-flooding-protection --disable-popup-blocking --disable-prompt-on-repost --disable-renderer-backgrounding --force-color-profile=srgb --metrics-recording-only --no-first-run --password-store=basic --use-mock-keychain --no-service-autorun --export-tagged-pdf --disable-search-engine-choice-screen --unsafely-disable-devtools-self-xss-warnings --enable-use-zoom-for-dsf=false --user-data-dir=/Users/colin/Library/Caches/ms-playwright/mcp-chrome-profile --remote-debugging-port=59893 about:blank
  - <launched> pid=64239
  - [pid=64239][out] Opening in existing browser session.
  - [pid=64239] <process did exit: exitCode=0, signal=null>
  - [pid=64239] starting temporary directories cleanup
  - <ws connecting> undefined

Thank you guys for your work on this MCP, I'm really enjoying it and this is my only issue with it right now! Hoping to mention you guys in a blogpost soon.

[mxschmitt]

Thank you for the feedback! Do you have multiple instances of Cursor open where you interact with Playwright MCP?

If so, then we recommend passing a different --user-data-dir <path> in each of them since otherwise they clash.

[clharman]

Nope just using the one instance.

[pavelfeldman]

When using MCP in server mode with multiple clients, you can't use persistent context. Make sure you pass --isolated in arguments.