What causes "This browser session does not support closing tabs" in jackwener/OpenCLI?

Use a session type that owns the browser and supports closing tabs

This browser session does not support closing tabs

Error message

This browser session does not support closing tabs

What it means

The `browser tab close` subcommand requires the page's optional closeTab capability; when the current session's page does not implement it, the CLI throws before attempting the close. Like 5266, this is a capability guard for sessions that cannot close tabs.

Source

Thrown at src/cli.ts:1228

    .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));
      console.log(JSON.stringify({ selected: resolvedTarget }, null, 2));
    }));

  addBrowserTabOption(browserTab.command('close')
    .argument('[targetId]', 'Target tab/page identity returned by "browser open", "browser tab new", or "browser tab list"')
    .description('Close a tab by target ID'))
    .action(browserAction(async (page, targetId?: string, opts?: { tab?: string } | Command) => {
      const resolvedTarget = resolveBrowserTabTarget(targetId, opts);
      if (!page.closeTab) {
        throw new Error('This browser session does not support closing tabs');
      }
      if (!resolvedTarget) {
        throw new Error('Target tab required. Pass it as an argument or --tab <targetId>.');
      }
      const validatedTarget = await resolveBrowserTargetInSession(page, resolvedTarget, {
        scope: getPageScope(page),
        source: 'explicit',
      });
      if (!validatedTarget) {
        throw new Error(`Target tab ${resolvedTarget} is not part of the current browser session.`);
      }
      await page.closeTab(validatedTarget);
      const scope = getPageScope(page);
      if (loadBrowserTargetState(scope)?.defaultPage === validatedTarget) {
        saveBrowserTargetState(undefined, scope);
      }
      console.log(JSON.stringify({ closed: validatedTarget }, null, 2));
    }));

View on GitHub (pinned to 49907e53dc)

Solutions

Use a session type that owns the browser and supports closing tabs
Verify the browser context permits closing targets (some managed contexts forbid it)
Update the adapter/driver to implement closeTab
Close the tab manually in the browser if the session cannot

Example fix

// before
opencli browser attached-session tab close 1A2B3C4D5E6F  // throws
// after
opencli browser launched-session tab close 1A2B3C4D5E6F

Defensive patterns

Strategy: try-catch

Validate before calling

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

Type guard

function supportsCloseTab(page: IPage): page is IPage & { closeTab: (targetId: string) => Promise<void> } {
  return typeof (page as { closeTab?: unknown }).closeTab === 'function';
}

Try / catch

try {
  await run(['opencli', 'browser', session, 'tab', 'close', targetId]);
} catch (e) {
  if (String((e as Error).message).includes('does not support closing tabs')) {
    console.error(`Session '${session}' cannot close tabs; close them in the browser or use a launched session.`);
    return;
  }
  throw e;
}

Prevention

Verify closeTab support on the session kind before scripting cleanup steps
Use CLI-owned/launched sessions for full tab lifecycle control
Fall back to manual browser cleanup for attached/managed contexts
Keep adapters current so capability methods exist

When it happens

Trigger: Running `opencli browser <session> tab close [targetId]` against a session whose page lacks closeTab (page.closeTab is undefined).

Common situations: Attached/externally managed browser contexts where the CLI may not close pages; restricted remote sessions; older adapter versions without closeTab.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/d7320868dc9d13c1. Report an issue: GitHub.