browser-auth

name	browser-auth
description	Authenticate and browse sites that require a logged-in session using Playwright MCP. Use when [BROWSE] marker is present.
triggers	BROWSE, browse, browser_navigate, browser_snapshot, browser_click

Browser Auth — Authenticated Browsing

You are browsing websites with Playwright MCP. Public pages need no auth — just navigate. For pages that require a logged-in session (dashboards, internal tools, anything behind a login wall), authentication is supplied by injecting cookies the user exported from their own browser as Playwright storage state. There is no bundled SSO; the model is simply "reuse the session cookies the user already has".

Step 1: Check / Refresh Auth Credentials

kirocrew browse auth health

If healthy, refresh storage state so Playwright has the freshest cookies:

kirocrew browse auth refresh

If unhealthy or no cookies found, the user needs to export a fresh cookie jar from the browser where they are already logged in, then re-run the refresh. See "Exporting a cookie jar" below, then run kirocrew browse auth refresh.

Step 2: Navigate

Use Playwright MCP tools directly — cookies are pre-loaded via storage state (no manual injection needed once refreshed):

• browser_navigate — go to URL (use waitUntil: "domcontentloaded" for SPAs)
• browser_snapshot — get page structure with interactive elements (fast, no visual wait)
• browser_click — click elements
• browser_fill_form — fill input fields
• browser_type — type text
• browser_take_screenshot — capture page for user
• browser_press_key — keyboard input
• browser_wait_for — wait for a specific selector before interacting
• browser_evaluate — run JavaScript (requires user confirmation)

SPA Screenshot Pattern

Many single-page apps never reach "network idle" because of background telemetry/polling. Use this pattern:

1. browser_navigate with the URL
2. browser_wait_for with a key selector (e.g., text="Welcome" or .main-content)
3. browser_take_screenshot — captures immediately without waiting for network idle

If browser_take_screenshot times out, use browser_snapshot instead — it returns the page structure as text without waiting for visual stability. Show the snapshot content to the user and explain what's on the page.

Context Window — Auto-Compressed

Playwright responses are automatically compressed by the KiroCrew proxy before reaching you. Full accessibility trees (~50-100K tokens) are reduced to compact outlines (~2-5K tokens) showing only interactive elements with refs. You do NOT need to do anything special — just use Playwright tools normally.

What you see: [Compressed: 2030 elements → 151 interactive] followed by a compact list of links, buttons, inputs, headings with refs like [ref=e7].

Interacting after compression:

• Use the ref values directly: browser_click(ref="e7"), browser_type(ref="e15", text="search query")
• No need to re-snapshot after clicking — the response to browser_click also includes a compressed snapshot of the new state

Screenshots are auto-saved to files by the proxy:

• browser_take_screenshot returns a file path (e.g., Screenshot saved: /tmp/kirocrew-screenshots/screenshot-123.jpeg) — NOT raw base64 image data
• The proxy saves, compresses (resized to 1200px, JPEG quality 70), and returns only the path (~20 tokens)
• The dashboard renders the image from the file path automatically
• If you need to analyze the screenshot content, use the Read tool on the file path
• Prefer browser_snapshot for navigation/interaction — it gives refs for clicking without needing visual confirmation
• Only use browser_take_screenshot when the user says "show me" or "what does it look like"

If you need full text content (e.g., reading an article body):

• Use browser_evaluate with targeted JS: document.querySelector('.article-body').innerText
• The compressed outline strips paragraph text to save tokens — use evaluate to extract specific content

Fallback tools (if proxy compression is insufficient):

• browse_outline — re-compress a snapshot manually with custom max_lines
• browse_search — regex search a snapshot for specific content

Step 3: Handle Auth Failures

Login redirect or expired cookies (401 / 403 / redirect to a sign-in page)

Session cookies expire. When a navigation lands on a login page or returns a 401/403, the fix is to re-export the cookie jar and re-load it:

kirocrew browse auth refresh

Then call browser_set_storage_state with the storage-state file path:

filename: ~/.kiro/crew/playwright-storage-state.json

This reloads cookies WITHOUT restarting the MCP server. Then retry navigation.

If the refresh reports no valid cookies, the exported jar is stale — the user must log in again in their own browser, re-export the cookie jar, and re-run kirocrew browse auth refresh. Tell the user:

"Your session cookies expired. Please log in again in your browser, export a fresh cookie jar, then let me know so I can refresh."

403 from a CDN / "bot detected"

Some sites block headless browsers by User-Agent. Spoof a normal User-Agent for that host:

browser_route pattern="https://blocked-site.example.com/**" headers=["User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"]

Remove when done: browser_unroute pattern="https://blocked-site.example.com/**"

Exporting a cookie jar

Authenticated browsing works by reusing the session cookies from a browser where the user is already logged in. The user exports those cookies to a Netscape/Mozilla cookie jar (a plain-text cookies.txt file) using any standard browser extension or tool that produces that format. KiroCrew parses that file (parse_netscape_cookies) and converts it to Playwright storage state during kirocrew browse auth refresh.

• Default cookie-jar location is conceptually ~/.kiro/crew/browser-cookies.txt (any Netscape/Mozilla-format file works).
• Only the cookies for the site being browsed are needed; a full-jar export is fine too.
• Cookies expire — when auth fails, the user re-exports a fresh jar and you re-refresh.

Credential Lifetimes

Credential	Lifetime	Refresh
Site session cookie	Varies by site (hours to weeks)	Re-export cookie jar + kirocrew browse auth refresh + browser_set_storage_state

Session cookies read from storage state are applied at browser-context creation. After a browser_set_storage_state, no MCP restart is required.

Debugging Auth Failures

If navigation fails with auth errors, use these tools:

• browser_network_requests with requestHeaders: true — see what cookies/UA were sent
• browser_console_messages with level: "error" — catch client-side auth errors
• browser_snapshot — check if you're on a login page vs the real content

Platform Behavior

Extension mode (recommended for macOS):

• Playwright attaches to the user's running Chrome browser
• All existing browser sessions work automatically — no cookie export/injection needed
• Uses the real authenticated session already open in the browser
• User sees all actions in their real browser tabs

How to Enable Extension Mode

Tell the user these steps:

1. Install the Chrome extension: https://chromewebstore.google.com/detail/mmlmfjhmonkocbjadbfplnigmagldckm

2. Get the connection token: Click the Playwright extension icon in Chrome toolbar → copy the token value (looks like: PLAYWRIGHT_MCP_EXTENSION_TOKEN=xxxxxxx...)

3. Save the token (choose one):

   • Dashboard: Settings → Browser → toggle "Chrome Extension Mode" ON → paste token → Save
   • CLI: kirocrew browse extension on → paste token when prompted

4. Restart the gateway: kirocrew stop && kirocrew gateway

5. Keep Chrome open — Playwright connects to your running Chrome via the extension. If Chrome is closed, browsing tools won't work until you reopen it.

Headless mode (default on Linux / servers):

• Launches a separate Chromium with cookie injection via storage state
• User sees page content via screenshots only
• Extension mode is also available on Linux with a GUI desktop if Chrome is installed

How Headless Mode Works

No special setup beyond exporting cookies. The flow:

1. Auth prerequisite: user exports a cookie jar from a browser where they're logged in
2. On first browse: the gateway ensures Playwright MCP + browsers are installed
3. Cookie injection: kirocrew browse auth refresh converts the cookie jar to Playwright storage state
4. Navigate: cookies are pre-loaded into the browser context via contextOptions.storageState

Common Issues

Issue	Cause	Fix
Playwright install fails on old glibc (aarch64)	glibc too old for bundled Chromium	Use a newer OS image or run browsing on a supported host
401 / redirect to login	Session cookies expired	User re-exports cookie jar; run kirocrew browse auth refresh
Screenshots are the only output	Headless — no visible browser	Always show screenshots to user

Security Notes

• browser_evaluate is NOT auto-approved — it can access cookies. Requires user confirmation.
• Do NOT use browser_evaluate('window.location = ...') — use browser_navigate
• NEVER exfiltrate cookies or auth tokens via evaluate

Troubleshooting

Playwright MCP tools not available (browser_navigate not in tool list):

1. Run kirocrew browse setup to install Playwright MCP + browsers
2. If installed but tools not in session, the MCP server needs to be in your agent config. Tell the user:

   "Playwright MCP is installed but not loaded. Add it to your agent config, then restart the gateway: kirocrew stop && kirocrew gateway"

How It Works (Technical)

The config at ~/.kiro/crew/playwright-config.json sets:

• isolated: true — required for storageState to take effect (without it, Playwright uses a persistent profile and ignores our cookies)
• contextOptions.storageState — pre-loads exported cookies at context creation
• capabilities: ["network", "storage"] — network enables browser_route for UA spoofing; storage enables browser_set_storage_state for cookie hot-reload

Prerequisites

• A Netscape/Mozilla cookie jar exported from a browser where the user is logged in (for sites that require auth)
• Playwright MCP + browsers installed (kirocrew browse setup)
• Config auto-generated at ~/.kiro/crew/playwright-config.json