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skills/sickn33/agentic-awesome-skills/claude-in-chrome-troubleshooting

claude-in-chrome-troubleshooting

1
sickn33/agentic-awesome-skills·Browser Automation·Audit pending·Snapshot eb3c094a1c80

Summary

This source did not publish a separate summary. Review SKILL.md before using the skill.

SKILL.md

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.

Two Native Hosts, Two Socket Formats

ComponentNative Host BinarySocket Location
Claude.app (Cowork)/Applications/Claude.app/Contents/Helpers/chrome-native-host/tmp/claude-mcp-browser-bridge-$USER/<PID>.sock
Claude Code CLI~/.local/share/claude/versions/<version> --chrome-native-host$TMPDIR/claude-mcp-browser-bridge-$USER (single file)

Why They Conflict

  1. Both register native messaging configs in Chrome:

  • com.anthropic.claude_browser_extension.json → Claude.app helper
  • 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.

    Diagnosis:

    cat ~/.claude/chrome/chrome-native-host
    # Bad: exec "/Users/.../.local/share/claude/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

    Claude Code 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 (Claude Code location) ==="
    ls -la "$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER" 2>&1
    
    echo -e "\n=== Socket (Claude.app location) ==="
    ls -la /tmp/claude-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|claude-mcp)"
    
    echo -e "\n=== Active Native Messaging Configs ==="
    ls ~/Library/Application\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic*.json 2>/dev/null
    
    echo -e "\n=== Custom Wrapper Contents ==="
    cat ~/.claude/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

    FilePurpose
    ~/.claude/chrome/chrome-native-hostCustom wrapper script for Claude Code
    /Applications/Claude.app/Contents/Helpers/chrome-native-hostClaude.app (Cowork) native host
    ~/.local/share/claude/versions/<version>Claude Code binary (run with --chrome-native-host)
    ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.jsonConfig for Claude.app native host
    ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.jsonConfig for Claude Code native host
    $TMPDIR/claude-mcp-browser-bridge-$USERSocket file (Claude Code)
    /tmp/claude-mcp-browser-bridge-$USER/<PID>.sockSocket files (Claude.app)

    Summary

    1. Primary issue: Claude.app (Cowork) and Claude Code 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 Claude Code (MCP connects at startup)
    4. One profile: Only have Claude extension in one Chrome profile
    5. 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.

    Limitations

    • Use this skill only when the task clearly matches the scope described above.
    • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
    • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

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