jackwener/OpenCLI · error

This browser session does not support creating tabs

Error message

This browser session does not support creating tabs

What it means

The `browser tab new` subcommand requires the page to support creating tabs via an optional page.newTab capability. Some session kinds (e.g. connected/attached contexts) do not implement it, so the CLI throws rather than failing mid-operation. It is a capability guard, not a user-argument error.

Source

Thrown at src/cli.ts:1200

    }));

  const browserTab = browser
    .command('tab')
    .description('Tab management — list, create, and close tabs in the browser session');

  browserTab.command('list')
    .description('List tabs in the browser session with target IDs')
    .action(browserAction(async (page) => {
      const tabs = await page.tabs();
      console.log(JSON.stringify(tabs, null, 2));
    }));

  browserTab.command('new')
    .argument('[url]', 'Optional URL to open in the new tab')
    .description('Create a new tab and print its target ID')
    .action(browserAction(async (page, url?: string) => {
      if (!page.newTab) {
        throw new Error('This browser session does not support creating tabs');
      }
      const createdPage = await page.newTab(url);
      console.log(JSON.stringify({
        page: createdPage,
        url: url ?? null,
      }, null, 2));
    }));

  addBrowserTabOption(browserTab.command('select')
    .argument('[targetId]', 'Target tab/page identity returned by "browser open", "browser tab new", or "browser tab list"')
    .description('Select a tab by target ID and make it the default browser tab'))
    .action(browserAction(async (page, targetId?: string, opts?: { tab?: string } | Command) => {
      const resolvedTarget = resolveBrowserTabTarget(targetId, opts);
      if (!resolvedTarget) {
        throw new Error('Target tab required. Pass it as an argument or --tab <targetId>.');
      }
      await page.selectTab(resolvedTarget);
      saveBrowserTargetState(resolvedTarget, getPageScope(page));

View on GitHub (pinned to 49907e53dc)

Solutions

  1. Use a session type that supports tab creation (launch/own the browser via the library)
  2. Check whether the underlying browser context allows opening new pages (popup blocking, CDP permissions)
  3. Update the browser adapter/driver to a version implementing newTab
  4. Work around by opening a new page in the browser manually and selecting it via `browser tab select <targetId>`

Example fix

// before
opencli browser attached-session tab new https://example.com  // throws
// after
opencli browser launched-session tab new https://example.com
Defensive patterns

Strategy: try-catch

Validate before calling

if (typeof (page as { newTab?: unknown }).newTab !== 'function') {
  throw new Error('This session does not support tab creation; use a launched browser session.');
}

Type guard

function supportsNewTab(page: IPage): page is IPage & { newTab: (url?: string) => Promise<IPage> } {
  return typeof (page as { newTab?: unknown }).newTab === 'function';
}

Try / catch

try {
  await run(['opencli', 'browser', session, 'tab', 'new', url]);
} catch (e) {
  if (String((e as Error).message).includes('does not support creating tabs')) {
    console.error(`Session '${session}' cannot create tabs. Launch a session owned by the CLI instead.`);
    return;
  }
  throw e;
}

Prevention

When it happens

Trigger: Running `opencli browser <session> tab new [url]` against a session whose page lacks a newTab implementation (page.newTab is undefined).

Common situations: Sessions attached to an externally managed browser that disallows tab creation; restricted/remote debugging contexts; older browser adapters without the capability.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/60e990d8d1d02ed5. Report an issue: GitHub.