Diagnose and fix Claude in Chrome MCP extension connectivity issues. Use when mcp__claude-in-chrome__* tools fail, return "Browser extension is not connected", or behave erratically.
Install
Use withClaudeCursorCodex
The file stays in the publisher's repository. PlugMCP does not host or rewrite it.
Diagnose and fix Claude in Chrome MCP extension connectivity issues. Use when mcp__claude-in-chrome__* tools fail, return "Browser extension is not connected", or behave erratically.
name: chrome-mcp-troubleshooting
description: Diagnose and fix Claude in Chrome MCP extension connectivity issues. Use when mcp__claude-in-chrome__* tools fail, return "Browser extension is not connected", or behave erratically.
Claude in Chrome MCP Troubleshooting
Use this skill when Claude in Chrome MCP tools fail to connect or work unreliably.
When to Use
mcp__claude-in-chrome__* tools fail with "Browser extension is not connected"
Browser automation works erratically or times out
After updating Claude Code or Claude.app
When switching between Claude Code CLI and Claude.app (Cowork)
Native host process is running but MCP tools still fail
When NOT to Use
Linux or Windows users - This skill covers macOS-specific paths and tools (~/Library/Application Support/, osascript)
General Chrome automation issues unrelated to the Claude extension
Claude.app desktop issues (not browser-related)
Network connectivity problems
Chrome extension installation issues (use Chrome Web Store support)
The Claude.app vs Claude Code Conflict (Primary Issue)
Background: When Claude.app added Cowork support (browser automation from the desktop app), it introduced a competing native messaging host that conflicts with Claude Code CLI.
com.anthropic.claude_code_browser_extension.json → Claude Code wrapper
Chrome extension requests a native host by name
If the wrong config is active, the wrong binary runs
The wrong binary creates sockets in a format/location the MCP client doesn't expect
Result: "Browser extension is not connected" even though everything appears to be running
The Fix: Disable Claude.app's Native Host
If you use Claude Code CLI for browser automation (not Cowork):
# Disable the Claude.app native messaging config
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json \
~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json.disabled
# Ensure the Claude Code config exists and points to the wrapper
cat ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json
If you use Cowork (Claude.app) for browser automation:
# Disable the Claude Code native messaging config
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json \
~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_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 CLAUDE_APP="$CONFIG_DIR/com.anthropic.claude_browser_extension.json"
local CLAUDE_CODE="$CONFIG_DIR/com.anthropic.claude_code_browser_extension.json"
if [[ -f "$CLAUDE_APP" && ! -f "$CLAUDE_APP.disabled" ]]; then
# Currently using Claude.app, switch to Claude Code
mv "$CLAUDE_APP" "$CLAUDE_APP.disabled"
[[ -f "$CLAUDE_CODE.disabled" ]] && mv "$CLAUDE_CODE.disabled" "$CLAUDE_CODE"
echo "Switched to Claude Code CLI"
echo "Restart Chrome and Claude Code to apply"
elif [[ -f "$CLAUDE_CODE" && ! -f "$CLAUDE_CODE.disabled" ]]; then
# Currently using Claude Code, switch to Claude.app
mv "$CLAUDE_CODE" "$CLAUDE_CODE.disabled"
[[ -f "$CLAUDE_APP.disabled" ]] && mv "$CLAUDE_APP.disabled" "$CLAUDE_APP"
echo "Switched to Claude.app (Cowork)"
echo "Restart Chrome to apply"
else
echo "Current state unclear. Check configs:"
ls -la "$CONFIG_DIR"/com.anthropic*.json* 2>/dev/null
fi
}
Usage: chrome-mcp-toggle then restart Chrome (and Claude Code if switching to CLI).
Quick Diagnosis
# 1. Which native host binary is running?
ps aux | grep chrome-native-host | grep -v grep
# Claude.app: /Applications/Claude.app/Contents/Helpers/chrome-native-host
# Claude Code: ~/.local/share/claude/versions/X.X.X --chrome-native-host
# 2. Where is the socket?
# For Claude Code (single file in TMPDIR):
ls -la "$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER" 2>&1
# For Claude.app (directory with PID files):
ls -la /tmp/claude-mcp-browser-bridge-$USER/ 2>&1
# 3. What's the native host connected to?
lsof -U 2>&1 | grep claude-mcp-browser-bridge
# 4. Which configs are active?
ls ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic*.json
Critical Insight
MCP connects at startup. If the browser bridge wasn't ready when Claude Code started, the connection will fail for the entire session. The fix is usually: ensure Chrome + extension are running with correct config, THEN restart Claude Code.
Full Reset Procedure (Claude Code CLI)
# 1. Ensure correct config is active
mv ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json \
~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json.disabled 2>/dev/null
# 2. Update the wrapper to use latest Claude Code version
cat > ~/.claude/chrome/chrome-native-host << 'EOF'
#!/bin/bash
LATEST=$(ls -t ~/.local/share/claude/versions/ 2>/dev/null | head -1)
exec "$HOME/.local/share/claude/versions/$LATEST" --chrome-native-host
EOF
chmod +x ~/.claude/chrome/chrome-native-host
# 3. Kill existing native host and clean sockets
pkill -f chrome-native-host
rm -rf /tmp/claude-mcp-browser-bridge-$USER/
rm -f "$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER"
# 4. Restart Chrome
osascript -e 'quit app "Google Chrome"' && sleep 2 && open -a "Google Chrome"
# 5. Wait for Chrome, click Claude extension icon
# 6. Verify correct native host is running
ps aux | grep chrome-native-host | grep -v grep
# Should show: ~/.local/share/claude/versions/X.X.X --chrome-native-host
# 7. Verify socket exists
ls -la "$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER"
# 8. Restart Claude Code
Other Common Causes
Multiple Chrome Profiles
If you have the Claude extension installed in multiple Chrome profiles, each spawns its own native host and socket. This can cause confusion.
Fix: Only enable the Claude extension in ONE Chrome profile.
Multiple Claude Code Sessions
Running multiple Claude Code instances can cause socket conflicts.
Fix: Only run one Claude Code session at a time, or use /mcp to reconnect after closing other sessions.
Hardcoded Version in Wrapper
The wrapper at ~/.claude/chrome/chrome-native-host may have a hardcoded version that becomes stale after updates.
Primary issue: Claude.app (Cowork) and Claude Code use different native hosts with incompatible socket formats
Fix: Disable the native messaging config for whichever one you're NOT using
After any fix: Must restart Chrome AND Claude Code (MCP connects at startup)
One profile: Only have Claude extension in one Chrome profile
One session: Only run one Claude Code instance
Original skill by @jeffzwang from @ExaAILabs. Enhanced and updated for current versions of Claude Desktop and Claude Code.
How do I install chrome-mcp-troubleshooting?
Download plugins/chrome-mcp-troubleshooting/skills/chrome-mcp-troubleshooting/SKILL.md from the publisher, or copy the path and open the repository. PlugMCP lists the skill and does not host the file.
Where does chrome-mcp-troubleshooting live?
The publisher keeps it at https://github.com/trailofbits/skills.
Which agents can use chrome-mcp-troubleshooting?
Claude, Cursor, and Codex can read a SKILL.md you add from the publisher's repository.