microsoft/playwright · error · Error

Arguments can not specify page to be opened

Error message

Arguments can not specify page to be opened

What it means

Firefox launch arguments must all be flags (start with `-`). A bare argument would be interpreted by Firefox as a URL/file to open, which conflicts with Playwright's BiDi-controlled session. `defaultArgs` rejects any arg not starting with `-`.

Source

Thrown at packages/playwright-core/src/server/bidi/bidiFirefox.ts:112

  override supportsPipeTransport(): boolean {
    return false;
  }

  override async prepareUserDataDir(options: types.LaunchOptions, userDataDir: string): Promise<void> {
    await createProfile({
      path: userDataDir,
      preferences: options.firefoxUserPrefs || {},
    });
  }

  override async defaultArgs(options: types.LaunchOptions, isPersistent: boolean, userDataDir: string) {
    const { args = [], headless } = options;
    const userDataDirArg = args.find(arg => arg.startsWith('-profile') || arg.startsWith('--profile'));
    if (userDataDirArg)
      throw this._createUserDataDirArgMisuseError('--profile');
    if (args.find(arg => !arg.startsWith('-')))
      throw new Error('Arguments can not specify page to be opened');
    const firefoxArguments = ['--remote-debugging-port=0'];
    if (headless)
      firefoxArguments.push('--headless');
    else
      firefoxArguments.push('--foreground');
    firefoxArguments.push(`--profile`, userDataDir);
    firefoxArguments.push(...args);
    return firefoxArguments;
  }

  override async waitForReadyState(options: types.LaunchOptions, browserLogsCollector: RecentLogsCollector): Promise<{ wsEndpoint?: string }> {
    const result = new ManualPromise<{ wsEndpoint?: string }>();
    browserLogsCollector.onMessage(message => {
      const match = message.match(/WebDriver BiDi listening on (ws:\/\/.*)$/);
      if (match)
        result.resolve({ wsEndpoint: match[1] + '/session' });
    });
    return result;

View on GitHub (pinned to c8fc3bf8d3)

Solutions

1. Remove URLs/bare values from `args`; navigate with `page.goto()` after launch
2. Use `baseURL` + `page.goto('/')` for startup navigation
3. If you need a profile, omit it — Playwright manages `--profile` itself

Example fix

// before
const b = await firefox.launch({ args: ['https://example.com'] });

// after
const b = await firefox.launch();
const p = await b.newPage();
await p.goto('https://example.com');

function sanitizeFirefoxArgs(args: string[]): string[] {
  const bad = args.filter(a => !a.startsWith('-'));
  if (bad.length) {
    throw new Error(
      `Firefox launch args must be flags (start with '-'). Non-flag values (${bad.join(', ')}) are not supported; use page.goto() instead.`
    );
  }
  return args;
}
await firefox.launch({ args: sanitizeFirefoxArgs(rawArgs) });

When it happens

Trigger: `firefox.launch({ args: ['https://example.com'] })`, `args: ['about:blank']`, or any non-flag value in launch args.

Common situations: Copy-pasting Chromium launch conventions (where a URL sometimes works) to Firefox; trying to open a startup URL via args instead of `page.goto`; passing profile paths without the `-profile` prefix.

Related errors

• Cannot launch Firefox with relative home directory. Did you
• Playwright manages remote debugging connection itself.
• Arguments can not specify page to be opened
• Arguments can not specify page to be opened
• JSHandle is not a DOM node handle

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/42d4d999f59277a8. Report an issue: GitHub.