TabbitBlog

How to Use Cline CLI with a Signed-In Browser

Diagnose Cline CLI browser access in order: skill discovery, local Tabbit CLI reachability, then the site’s existing login session.

In this article
  1. Key takeaways
  2. Cline and Tabbit at a glance
  3. Troubleshoot the three connections separately
  4. 1. Check Cline’s skill discovery
  5. 2. Check that the local launcher is reachable
  6. 3. Check the site session without changing anything
  7. Use a review checkpoint for an acceptance page
  8. When the problem is not Cline

If you run Cline CLI locally and need it to inspect a page where you are already signed in, check three things in order: whether Cline sees the Tabbit skill, whether its terminal can launch Tabbit CLI, and whether the target page is authenticated in Tabbit Browser. Tabbit Browser plus Tabbit CLI is a practical route for this workflow; the checks below help locate the failure before you hand over a real page.

A Cline user asking whether it could run code, read terminal and browser errors, then fix small issues described a familiar friction: the terminal session changed when the agent needed to run a second command. That post is about an older Cline setup, so treat it as a troubleshooting clue, not evidence about current CLI behavior. (Reddit discussion)

Key takeaways

  • Cline CLI is installed with npm i -g cline; its official overview says to authenticate a model provider with cline auth before using it.

  • Start by checking whether Cline can see the Tabbit skill. Client skill discovery is different from launching the local browser CLI.

  • Keep --auto-approve false for an initial run. Cline currently documents true as the global default.

  • Sign in to the target site yourself in Tabbit Browser, then ask the agent to read a harmless heading before it does any work that changes data.

  • A successful local CLI call does not prove the site session works. Verify both separately.

Cline and Tabbit at a glance

CheckWhat to verifySafe signal
Cline setupcline starts and a provider is authenticatedCLI opens and a simple prompt returns
Skill discoveryTabbit skill appears in Cline’s skill list or slash suggestions/tabbit is offered, or the skill is otherwise listed
Local launcherCline can run the installed tabbit-cli commanddiagnose returns the expected Tabbit browser status
Site sessionThe target URL opens in Tabbit under your existing accountA known page heading appears without a login redirect
Task boundaryThe agent reads a page before taking actionOutput includes the expected title and URL

Cline’s CLI overview documents installation, provider authentication, interactive and headless use, plus the --auto-approve <boolean> flag. The Skills guide explains that Cline discovers skills in workspace .cline/skills/ and personal ~/.cline/skills/ folders. Tabbit’s quick start describes its own agent install locations. Those locations may not be the same for every client, so check what this Cline installation actually loads instead of assuming /tabbit works.

Troubleshoot the three connections separately

1. Check Cline’s skill discovery

Install or update Cline using its current official instructions, start it from your project, and confirm that the provider you plan to use is available. The provider/model choice belongs to Cline; browser control belongs to the local Tabbit CLI. Check the provider catalogue in your own Cline configuration before naming a particular model.

Type / in Cline’s interactive prompt and look for tabbit. If it is absent, inspect the skill list and the paths Cline documents for your version. Cline supports .cline/skills/<name>/SKILL.md in a workspace and ~/.cline/skills/<name>/SKILL.md for personal use. Tabbit’s installation guide lists ~/.agents/skills/tabbit/SKILL.md for compatible agents. Do not assume Cline imports that directory. If you use a supported skill location, make it available there, restart Cline, and check / again.

2. Check that the local launcher is reachable

With Tabbit Browser open, run the installed launcher in a terminal:

$HOME/.local/bin/tabbit-cli diagnose

The command should report the Tabbit controller and browser state. If it fails, repair the local installation or connection before asking Cline to browse. Then ask Cline to run that same read-only diagnostic with approvals on. Cline CLI’s documented default is --auto-approve true; turn that off explicitly for this task:

cline --auto-approve false "Run $HOME/.local/bin/tabbit-cli diagnose and summarize the browser status. Do not open a site or change any data."

Cline documents --auto-approve false as the boolean flag form. A successful diagnostic only proves the CLI can reach Tabbit; it says nothing about the website’s login session.

3. Check the site session without changing anything

Open the target site yourself in Tabbit Browser and sign in. Ask Cline to use Tabbit to visit one known page and return its URL and heading. Do not ask it to submit, save, or send anything during this check. If the page redirects to sign-in, the site session is missing or expired. If the CLI reports no connected browser, the launcher connection is the issue. If the skill is missing, fix discovery first.

The diagnostic order matters because each failure points to a different repair:

SymptomLikely layerNext check
/tabbit is not offeredSkill discoveryCline’s loaded skills and supported path
Shell says command not foundLauncher installation or PATHRun the absolute launcher path directly
diagnose cannot find a browserTabbit controller or instanceOpen Tabbit and follow its CLI recovery steps
Page shows a sign-in formWebsite sessionSign in manually in Tabbit, then retry a read-only page check
Page reads correctly but action is wrongTask scope or page stateNarrow the prompt and inspect the page before continuing

Use a review checkpoint for an acceptance page

Once the read-only check passes, make a separate task for a test or staging page. Keep the request bounded and ask Cline to show evidence before making edits:

/tabbit Open the acceptance page already signed in in Tabbit Browser.
Read the page title, URL, and the visible status for case QA-104.
Do not submit forms or change account settings.
Return a short report and save it locally as cline-qa-104-review.md.
Stop after showing me the draft so I can review it.

Use /tabbit only if Cline has shown that slash command for the installed skill; otherwise ask Cline to load the discovered skill by its displayed name. The named file and stopping point make the result reviewable. Confirm the title, URL, case ID, and draft contents yourself. Do not treat a plausible summary as proof that a server-side change happened.

Tabbit CLI can run a task in its own browser tab, while you continue using other tabs. In a local fixture check on November 9, 2026, a protected page first returned 401; after a short-lived test cookie was set, a second task read the fixture heading and record in its own tab. That verifies session reuse for this Tabbit environment and fixture only. It does not establish a Cline-to-Tabbit integration test or say anything about your production site. For a broader browser agent workflow, keep the human sign-in and review step explicit. The Tabbit CLI setup guide covers the client-side install path, while the Playwright MCP setup guide covers a different browser connection.

When the problem is not Cline

Cline CLI’s own browser behavior and the VS Code extension’s tools may differ. Confirm the CLI’s available skills and tools before following an extension tutorial. If Cline can launch the Tabbit command but the site still asks you to log in, do not troubleshoot model selection. Check the account, domain, browser profile, and session expiry in Tabbit first.

For repeatable web tasks, keep a small first browser agent task checklist, and use browser automation guidance when deciding whether a task needs a browser or a direct API. A prompt template can make the read-only boundary explicit. If the page is part of a research workflow or a web-to-CSV task, specify the fields you need before starting. If the agent should only read the page, avoid write actions. If it must change a record, stop for a human checkpoint before the final save.

FAQ

Can Cline CLI use my logged-in browser?

Cline CLI can run a local command, and Tabbit CLI can operate in Tabbit Browser. Confirm that Cline can discover the Tabbit skill or run the launcher, then verify the target site session in Tabbit. The connection is a local workflow check, not proof that every Cline setup has native browser access.

What should I type to invoke Tabbit from Cline?

If Cline lists the installed Tabbit skill as a slash command, use `/tabbit` followed by a narrow task. If it does not appear, inspect Cline’s discovered skill locations and restart the CLI; do not assume that a skill installed for another client is automatically visible.

Does Cline CLI share the VS Code extension’s browser tools?

Do not assume it does. The CLI and VS Code extension are separate entry points, and their tools can differ by version and configuration. Check the CLI’s visible tools and test one harmless page before using an authenticated site.

How do I keep Cline from approving every browser action?

Pass `--auto-approve false` for the run and review any approval prompt. Cline’s CLI overview currently documents global auto-approval as enabled by default, so check this setting before starting.

Does the browser task sign in for me?

No. Sign in to the site yourself in Tabbit Browser first. The CLI can then work with the session already present in that browser environment, subject to the site and task permissions.

Can I keep using the browser while Cline works?

Tabbit CLI creates a task-owned tab for its work, so you can continue in other browser tabs. Review the task output and the page state before relying on a change.

Take the next step

Let Tabbit work alongside you.

Research across tabs, automate repetitive browser work, and keep every piece of context within reach.