Gemini In Chrome Troubleshooting

Background: When Gemini.app added Cowork support (browser automation from the desktop app), it introduced a competing native messaging host that conflicts with Gemini CLI CLI.

Two Native Hosts, Two Socket Formats

Why They Conflict

1. Both register native messaging configs in Chrome:

   • com.gemini.gemini_browser_extension.json → Gemini.app helper
   • com.gemini.gemini_code_browser_extension.json → Gemini CLI wrapper

2. Chrome extension requests a native host by name

3. If the wrong config is active, the wrong binary runs

4. The wrong binary creates sockets in a format/location the MCP client doesn't expect

5. Result: "Browser extension is not connected" even though everything appears to be running

The Fix: Disable Gemini.app's Native Host

If you use Gemini CLI CLI for browser automation (not Cowork):

# Disable the Gemini.app native messaging config
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_browser_extension.json \
   ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_browser_extension.json.disabled

# Ensure the Gemini CLI config exists and points to the wrapper
cat ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_code_browser_extension.json

If you use Cowork (Gemini.app) for browser automation:

# Disable the Gemini CLI native messaging config
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_code_browser_extension.json \
   ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_code_browser_extension.json.disabled

You cannot use both simultaneously. Pick one and disable the other.

Toggle Script

Add this to ~/.zshrc or run directly:

chrome-mcp-toggle() {
    local CONFIG_DIR=~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts
    local GEMINI_APP="$CONFIG_DIR/com.gemini.gemini_browser_extension.json"
    local GEMINI_CLI="$CONFIG_DIR/com.gemini.gemini_code_browser_extension.json"

    if [[ -f "$GEMINI_APP" && ! -f "$GEMINI_APP.disabled" ]]; then
        # Currently using Gemini.app, switch to Gemini CLI
        mv "$GEMINI_APP" "$GEMINI_APP.disabled"
        [[ -f "$GEMINI_CLI.disabled" ]] && mv "$GEMINI_CLI.disabled" "$GEMINI_CLI"
        echo "Switched to Gemini CLI CLI"
        echo "Restart Chrome and Gemini CLI to apply"
    elif [[ -f "$GEMINI_CLI" && ! -f "$GEMINI_CLI.disabled" ]]; then
        # Currently using Gemini CLI, switch to Gemini.app
        mv "$GEMINI_CLI" "$GEMINI_CLI.disabled"
        [[ -f "$GEMINI_APP.disabled" ]] && mv "$GEMINI_APP.disabled" "$GEMINI_APP"
        echo "Switched to Gemini.app (Cowork)"
        echo "Restart Chrome to apply"
    else
        echo "Current state unclear. Check configs:"
        ls -la "$CONFIG_DIR"/com.gemini*.json* 2>/dev/null
    fi
}

Usage: chrome-mcp-toggle then restart Chrome (and Gemini CLI if switching to CLI).

Quick Diagnosis

# 1. Which native host binary is running?
ps aux | grep chrome-native-host | grep -v grep
# Gemini.app: /Applications/Gemini.app/Contents/Helpers/chrome-native-host
# Gemini CLI: ~/.local/share/gemini/versions/X.X.X --chrome-native-host

# 2. Where is the socket?
# For Gemini CLI (single file in TMPDIR):
ls -la "$(getconf DARWIN_USER_TEMP_DIR)/gemini-mcp-browser-bridge-$USER" 2>&1

# For Gemini.app (directory with PID files):
ls -la /tmp/gemini-mcp-browser-bridge-$USER/ 2>&1

# 3. What's the native host connected to?
lsof -U 2>&1 | grep gemini-mcp-browser-bridge

# 4. Which configs are active?
ls ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini*.json

Critical Insight

MCP connects at startup. If the browser bridge wasn't ready when Gemini CLI started, the connection will fail for the entire session. The fix is usually: ensure Chrome + extension are running with correct config, THEN restart Gemini CLI.

Full Reset Procedure (Gemini CLI CLI)

# 1. Ensure correct config is active
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_browser_extension.json \
   ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini.gemini_browser_extension.json.disabled 2>/dev/null

# 2. Update the wrapper to use latest Gemini CLI version
cat > ~/.gemini/chrome/chrome-native-host << 'EOF'
#!/bin/bash
LATEST=$(ls -t ~/.local/share/gemini/versions/ 2>/dev/null | head -1)
exec "$HOME/.local/share/gemini/versions/$LATEST" --chrome-native-host
EOF
chmod +x ~/.gemini/chrome/chrome-native-host

# 3. Kill existing native host and clean sockets
pkill -f chrome-native-host
rm -rf /tmp/gemini-mcp-browser-bridge-$USER/
rm -f "$(getconf DARWIN_USER_TEMP_DIR)/gemini-mcp-browser-bridge-$USER"

# 4. Restart Chrome
osascript -e 'quit app "Google Chrome"' && sleep 2 && open -a "Google Chrome"

# 5. Wait for Chrome, click Gemini extension icon

# 6. Verify correct native host is running
ps aux | grep chrome-native-host | grep -v grep
# Should show: ~/.local/share/gemini/versions/X.X.X --chrome-native-host

# 7. Verify socket exists
ls -la "$(getconf DARWIN_USER_TEMP_DIR)/gemini-mcp-browser-bridge-$USER"

# 8. Restart Gemini CLI

Other Common Causes

Multiple Chrome Profiles

If you have the Gemini extension installed in multiple Chrome profiles, each spawns its own native host and socket. This can cause confusion.

Fix: Only enable the Gemini extension in ONE Chrome profile.

Multiple Gemini CLI Sessions

Running multiple Gemini CLI instances can cause socket conflicts.

Fix: Only run one Gemini CLI session at a time, or use /mcp to reconnect after closing other sessions.

Hardcoded Version in Wrapper

The wrapper at ~/.gemini/chrome/chrome-native-host may have a hardcoded version that becomes stale after updates.

Diagnosis:

cat ~/.gemini/chrome/chrome-native-host
# Bad: exec "/Users/.../.local/share/gemini/versions/2.0.76" --chrome-native-host
# Good: Uses $(ls -t ...) to find latest

Fix: Use the dynamic version wrapper shown in the Full Reset Procedure above.

TMPDIR Not Set

Gemini CLI expects TMPDIR to be set to find the socket.

# Check
echo $TMPDIR
# Should show: /var/folders/XX/.../T/

# Fix: Add to ~/.zshrc
export TMPDIR="${TMPDIR:-$(getconf DARWIN_USER_TEMP_DIR)}"

Diagnostic Deep Dive

echo "=== Native Host Binary ==="
ps aux | grep chrome-native-host | grep -v grep

echo -e "\n=== Socket (Gemini CLI location) ==="
ls -la "$(getconf DARWIN_USER_TEMP_DIR)/gemini-mcp-browser-bridge-$USER" 2>&1

echo -e "\n=== Socket (Gemini.app location) ==="
ls -la /tmp/gemini-mcp-browser-bridge-$USER/ 2>&1

echo -e "\n=== Native Host Open Files ==="
pgrep -f chrome-native-host | xargs -I {} lsof -p {} 2>/dev/null | grep -E "(sock|gemini-mcp)"

echo -e "\n=== Active Native Messaging Configs ==="
ls ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.gemini*.json 2>/dev/null

echo -e "\n=== Custom Wrapper Contents ==="
cat ~/.gemini/chrome/chrome-native-host 2>/dev/null || echo "No custom wrapper"

echo -e "\n=== TMPDIR ==="
echo "TMPDIR=$TMPDIR"
echo "Expected: $(getconf DARWIN_USER_TEMP_DIR)"

File Reference

Summary

1. Primary issue: Gemini.app (Cowork) and Gemini CLI use different native hosts with incompatible socket formats
2. Fix: Disable the native messaging config for whichever one you're NOT using
3. After any fix: Must restart Chrome AND Gemini CLI (MCP connects at startup)
4. One profile: Only have Gemini extension in one Chrome profile
5. One session: Only run one Gemini CLI instance

Original skill by @jeffzwang from @ExaAILabs. Enhanced and updated for current versions of Gemini Desktop and Gemini CLI.