Claude in Chrome: "Browser extension is not connected" despite correct native host setup (macOS 26 + Chrome 145)

Description

claude --chrome consistently fails to connect to the Chrome browser extension with the message "Browser extension is not connected", despite all configuration being verified correct.

Environment

• OS: macOS 26.3.1 (Darwin 25.3.0, Apple Silicon)
• Chrome: 145.0.7632.160
• Claude Code CLI: 2.1.71 (Homebrew cask)
• Node: v24.12.0
• Extension version: 1.0.58
• Extension ID: fcoeoabgfenejglbffodgkkbkcdhcgfn (matches allowed_origins)
• Chrome Profile: Default (single active profile)

What works

• Native host config correctly placed at ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json
• Native host binary exists and is executable: /Users/atsushi/.claude/chrome/chrome-native-host
• Native host process is running (single instance): /opt/homebrew/Caskroom/claude-code/2.1.71/claude --chrome-native-host
• Unix socket created and listening: /tmp/claude-mcp-browser-bridge-atsushi/<pid>.sock (permissions 0600)
• Extension installed in correct profile (Default) with nativeMessaging permission
• Extension Service Worker shows no errors in DevTools console
• Claude Desktop native host disabled (.bak/.disabled)
• Logged into claude.ai with the same account as Claude Code CLI
• Extension ID matches allowed_origins in native host config

What doesn't work

• mcp__claude-in-chrome__tabs_context_mcp always returns "Browser extension is not connected"
• Tried: reinstalling extension, toggling extension on/off, reloading claude.ai tab, restarting CLI session

Steps to reproduce

1. Install Claude Chrome extension (ID: fcoeoabgfenejglbffodgkkbkcdhcgfn)
2. Open claude.ai and log in
3. Run claude --chrome
4. Any mcp__claude-in-chrome__* tool call returns "Browser extension is not connected"

Not yet tried

• Deleting socket directory and restarting both Chrome and CLI in sequence
• Complete Chrome data reset

Additional context

• Two Chrome profiles exist (Default and Profile 1), extension is in Default which is the active profile
• Previously had Claude Desktop native host (com.anthropic.claude_browser_extension.json), now disabled via rename