chrome-health-check

Chrome Connection Health Check

Run a quick connection test. If broken, diagnose the root cause and fix it.

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Step 1: Test the connection

Call tabs_context_mcp with createIfEmpty: false.

If successful (returns tab info or "no tab group exists"): → Report: "✅ Chrome is connected and ready." Stop here.

If it returns "No Chrome extension connected after discovery": → Report: "❌ Chrome extension not connected — diagnosing now…" → Proceed to Step 2.

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Step 2: Diagnose — Account Mismatch (most common cause)

The #1 root cause is an account mismatch between the Desktop App and the Chrome extension. The bridge WebSocket is namespaced per user UUID — if the two sides use different accounts, they can never find each other.

Check Desktop App account

python3 -c "
import glob, re
pattern = '/Users/*/Library/Application Support/Claude/Local Storage/leveldb/*.ldb'
for f in glob.glob(pattern):
    try:
        data = open(f,'rb').read().decode('utf-8','ignore')
        email = re.search(r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}', data)
        uid = re.search(r'[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}', data)
        if email: print('Desktop email:', email.group())
        if uid: print('Desktop UUID:', uid.group())
    except: pass
"

Also check the bridge URL in the log:

grep "Connecting to bridge" ~/Library/Logs/Claude/main.log | tail -3

Check extension account

Navigate to: chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/options.html

The top-right shows the logged-in email. Compare it with the Desktop App account.

If they match → accounts are correct, skip to Step 3b. If they differ → account mismatch confirmed → go to Step 3a.

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Step 3a: Fix Account Mismatch

3a-1: Log out the extension

On the extension options page (chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/options.html), click "Log out".

3a-2: Switch Claude.ai browser session to the correct account

1. Navigate to https://claude.ai/logout
2. On the login page, click "Continue with email"
3. Enter the correct email (same as Desktop App — e.g. ms.apps@msapps.mobi)
4. Claude.ai sends a magic link to that email
5. Open the email inbox for that address and click the magic link:
   • For ms.apps@msapps.mobi (Zoho Workplace): https://workplace.zoho.com/#mail_app/mail/folder/inbox
   • The magic link email arrives within ~1 minute from noreply@...mail.anthropic.com
   • Subject: "Secure link to log in to Claude.ai | {timestamp}"
   • Note: ms.apps@msapps.mobi magic link emails are delivered to the michal@msapps.mobi Zoho inbox (same org)
6. Clicking the link logs Claude.ai into the correct account in this browser

3a-3: Re-authenticate the extension

After Claude.ai is signed in with the correct account:

• Reload chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/options.html
• Click "Log in" — the extension OAuth uses the active Claude.ai session automatically
• Confirm the options page now shows the correct email in the top-right

3a-4: Restart the Claude Desktop App

discoverAndSelectExtension() runs once at startup and sets discoveryComplete=true. Every subsequent tool call throws the error permanently until the app restarts.

osascript -e 'quit app "Claude"'
sleep 3
open -a Claude
sleep 5

Then retest with tabs_context_mcp.

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Step 3b: Other fixes (non-account-mismatch)

If accounts match but still broken:

Extension not installed/enabled:

• Go to chrome://extensions/ → confirm fcoeoabgfenejglbffodgkkbkcdhcgfn is enabled

Extension token expired:

• Log out and back in on the extension options page

Bridge WebSocket down or Chrome not focused:

osascript -e 'quit app "Google Chrome"'
sleep 2
open -a "Google Chrome"
sleep 3
osascript -e 'quit app "Claude"'
sleep 2
open -a Claude

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Quick Reference: MSApps Account Mapping

Side	Account	UUID
Claude Desktop App (correct)	ms.apps@msapps.mobi	da5d00b9-5ca9-40ea-a8b5-5052603ff35b
Chrome extension (correct)	ms.apps@msapps.mobi	da5d00b9-5ca9-40ea-a8b5-5052603ff35b
Chrome extension (wrong/old)	msmobileapps@gmail.com	22a74de5-a2af-47b2-b30e-eab1eb168f03

Bridge URL: wss://bridge.claudeusercontent.com/chrome/{UUID} — both sides must share the same UUID.

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Root Cause Summary (diagnosed April 2026)

Desktop App switched accounts (Apr 2) to ms.apps@msapps.mobi. Chrome extension kept old credentials (msmobileapps@gmail.com). Bridge namespaces don't overlap → discovery found nothing → discoveryComplete=true got permanently stuck. Fix: log out extension → sign Claude.ai into correct account via magic link → extension re-authenticates via OAuth → restart Desktop App.