{"slug":"chrome-mcp-troubleshooting","title":"chrome-mcp-troubleshooting","summary":"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.","platform":"Claude","tags":[],"authorName":"LLM Mart","authorSlug":"llm-mart","score":0,"source":"github","price":null,"verified":false,"createdAt":"2026-09-06T18:19:37.465653Z","repo":{"url":"https://github.com/trailofbits/skills","stars":7234,"forks":616,"license":"CC-BY-SA-4.0","updatedAt":"2026-09-25T07:34:17Z"},"bodyHtml":"
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name: chrome-mcp-troubleshooting\ndescription: 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.

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Claude in Chrome MCP Troubleshooting

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Use this skill when Claude in Chrome MCP tools fail to connect or work unreliably.

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When to Use

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When NOT to Use

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The Claude.app vs Claude Code Conflict (Primary Issue)

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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.

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Two Native Hosts, Two Socket Formats

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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)
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Why They Conflict

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  1. Both register native messaging configs in Chrome:

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    2. \n

  2. Chrome extension requests a native host by name

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    3. \n

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

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    4. \n

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

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    5. \n

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

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    6. \n
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The Fix: Disable Claude.app's Native Host

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

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# Disable the Claude.app native messaging config\nmv ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json \\\n   ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json.disabled\n\n# Ensure the Claude Code config exists and points to the wrapper\ncat ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json\n
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If you use Cowork (Claude.app) for browser automation:

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# Disable the Claude Code native messaging config\nmv ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json \\\n   ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json.disabled\n
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You cannot use both simultaneously. Pick one and disable the other.

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Toggle Script

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Add this to ~/.zshrc or run directly:

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chrome-mcp-toggle() {\n    local CONFIG_DIR=~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts\n    local CLAUDE_APP=\"$CONFIG_DIR/com.anthropic.claude_browser_extension.json\"\n    local CLAUDE_CODE=\"$CONFIG_DIR/com.anthropic.claude_code_browser_extension.json\"\n\n    if [[ -f \"$CLAUDE_APP\" && ! -f \"$CLAUDE_APP.disabled\" ]]; then\n        # Currently using Claude.app, switch to Claude Code\n        mv \"$CLAUDE_APP\" \"$CLAUDE_APP.disabled\"\n        [[ -f \"$CLAUDE_CODE.disabled\" ]] && mv \"$CLAUDE_CODE.disabled\" \"$CLAUDE_CODE\"\n        echo \"Switched to Claude Code CLI\"\n        echo \"Restart Chrome and Claude Code to apply\"\n    elif [[ -f \"$CLAUDE_CODE\" && ! -f \"$CLAUDE_CODE.disabled\" ]]; then\n        # Currently using Claude Code, switch to Claude.app\n        mv \"$CLAUDE_CODE\" \"$CLAUDE_CODE.disabled\"\n        [[ -f \"$CLAUDE_APP.disabled\" ]] && mv \"$CLAUDE_APP.disabled\" \"$CLAUDE_APP\"\n        echo \"Switched to Claude.app (Cowork)\"\n        echo \"Restart Chrome to apply\"\n    else\n        echo \"Current state unclear. Check configs:\"\n        ls -la \"$CONFIG_DIR\"/com.anthropic*.json* 2>/dev/null\n    fi\n}\n
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Usage: chrome-mcp-toggle then restart Chrome (and Claude Code if switching to CLI).

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Quick Diagnosis

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# 1. Which native host binary is running?\nps aux | grep chrome-native-host | grep -v grep\n# Claude.app: /Applications/Claude.app/Contents/Helpers/chrome-native-host\n# Claude Code: ~/.local/share/claude/versions/X.X.X --chrome-native-host\n\n# 2. Where is the socket?\n# For Claude Code (single file in TMPDIR):\nls -la \"$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER\" 2>&1\n\n# For Claude.app (directory with PID files):\nls -la /tmp/claude-mcp-browser-bridge-$USER/ 2>&1\n\n# 3. What's the native host connected to?\nlsof -U 2>&1 | grep claude-mcp-browser-bridge\n\n# 4. Which configs are active?\nls ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic*.json\n
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Critical Insight

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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.

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Full Reset Procedure (Claude Code CLI)

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# 1. Ensure correct config is active\nmv ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json \\\n   ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json.disabled 2>/dev/null\n\n# 2. Update the wrapper to use latest Claude Code version\ncat > ~/.claude/chrome/chrome-native-host << 'EOF'\n#!/bin/bash\nLATEST=$(ls -t ~/.local/share/claude/versions/ 2>/dev/null | head -1)\nexec \"$HOME/.local/share/claude/versions/$LATEST\" --chrome-native-host\nEOF\nchmod +x ~/.claude/chrome/chrome-native-host\n\n# 3. Kill existing native host and clean sockets\npkill -f chrome-native-host\nrm -rf /tmp/claude-mcp-browser-bridge-$USER/\nrm -f \"$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER\"\n\n# 4. Restart Chrome\nosascript -e 'quit app \"Google Chrome\"' && sleep 2 && open -a \"Google Chrome\"\n\n# 5. Wait for Chrome, click Claude extension icon\n\n# 6. Verify correct native host is running\nps aux | grep chrome-native-host | grep -v grep\n# Should show: ~/.local/share/claude/versions/X.X.X --chrome-native-host\n\n# 7. Verify socket exists\nls -la \"$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER\"\n\n# 8. Restart Claude Code\n
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Other Common Causes

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Multiple Chrome Profiles

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

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

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Multiple Claude Code Sessions

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Running multiple Claude Code instances can cause socket conflicts.

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

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Hardcoded Version in Wrapper

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

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Diagnosis:

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cat ~/.claude/chrome/chrome-native-host\n# Bad: exec \"/Users/.../.local/share/claude/versions/2.0.76\" --chrome-native-host\n# Good: Uses $(ls -t ...) to find latest\n
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Fix: Use the dynamic version wrapper shown in the Full Reset Procedure above.

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TMPDIR Not Set

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Claude Code expects TMPDIR to be set to find the socket.

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# Check\necho $TMPDIR\n# Should show: /var/folders/XX/.../T/\n\n# Fix: Add to ~/.zshrc\nexport TMPDIR=\"${TMPDIR:-$(getconf DARWIN_USER_TEMP_DIR)}\"\n
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Diagnostic Deep Dive

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echo \"=== Native Host Binary ===\"\nps aux | grep chrome-native-host | grep -v grep\n\necho -e \"\\n=== Socket (Claude Code location) ===\"\nls -la \"$(getconf DARWIN_USER_TEMP_DIR)/claude-mcp-browser-bridge-$USER\" 2>&1\n\necho -e \"\\n=== Socket (Claude.app location) ===\"\nls -la /tmp/claude-mcp-browser-bridge-$USER/ 2>&1\n\necho -e \"\\n=== Native Host Open Files ===\"\npgrep -f chrome-native-host | xargs -I {} lsof -p {} 2>/dev/null | grep -E \"(sock|claude-mcp)\"\n\necho -e \"\\n=== Active Native Messaging Configs ===\"\nls ~/Library/Application\\ Support/Google/Chrome/NativeMessagingHosts/com.anthropic*.json 2>/dev/null\n\necho -e \"\\n=== Custom Wrapper Contents ===\"\ncat ~/.claude/chrome/chrome-native-host 2>/dev/null || echo \"No custom wrapper\"\n\necho -e \"\\n=== TMPDIR ===\"\necho \"TMPDIR=$TMPDIR\"\necho \"Expected: $(getconf DARWIN_USER_TEMP_DIR)\"\n
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File Reference

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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)
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Summary

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  1. Primary issue: Claude.app (Cowork) and Claude Code use different native hosts with incompatible socket formats
    2. \n
  2. Fix: Disable the native messaging config for whichever one you're NOT using
    3. \n
  3. After any fix: Must restart Chrome AND Claude Code (MCP connects at startup)
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  4. One profile: Only have Claude extension in one Chrome profile
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  5. One session: Only run one Claude Code instance
    6. \n
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Original skill by @jeffzwang from @ExaAILabs. Enhanced and updated for current versions of Claude Desktop and Claude Code.

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