claude-code - 💡(How to fix) Fix Claude in Chrome MCP returns "not connected" despite all plumbing healthy (Claude Desktop on macOS) [3 comments, 2 participants]

### Summary
The `mcp__Claude_in_Chrome__*` tools (`list_connected_browsers`, `switch_browser`) consistently return *"Claude in Chrome is not connected. The Chrome extension isn't reachable right now."* — even though every layer of the integration is verifiably alive, the connector is enabled, and the side-panel agent (which uses the same native-messaging bridge) works correctly in the same browser.

### Environment
- macOS 25.4.0 (Darwin)
- Claude Desktop: 1.4758.0 (`com.anthropic.claudefordesktop`)
- Claude Code (CLI bundled inside desktop): 2.1.119 / Agent SDK 0.2.119
- Model: `claude-opus-4-7[1m]`
- Account: Max plan, single account on both Desktop and Chrome extension
- `CLAUDE_CODE_ENTRYPOINT=claude-desktop` (CLI launched as a child of Claude Desktop)
- Google Chrome: latest, signed into same Google profile
- Claude in Chrome (Beta) extension v1.0.69, ID `fcoeoabgfenejglbffodgkkbkcdhcgfn`, signed in as the same Anthropic account

### Reproduction
1. Open Claude Desktop, ensure the "Claude in Chrome" connector is **Enabled** (Settings → Connectors → Claude in Chrome [Beta]).
2. Have Chrome open with the Claude in Chrome (Beta) extension installed and signed in.
3. Confirm side-panel agent works (e.g., ask the side panel to "open a new tab and search Google for hello" — succeeds).
4. From a Claude Code session under the same Desktop instance, call:
   - `mcp__Claude_in_Chrome__list_connected_browsers` → `"not connected"`
   - `mcp__Claude_in_Chrome__switch_browser` (broadcast pairing) → `"not connected"` (no popup ever appears in the extension)
5. Retrying multiple times over several minutes does not recover.

### Diagnostics gathered

| Check | Result |
|---|---|
| Native-messaging host manifest at `~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json` | ✅ Present, points to `/Applications/Claude.app/Contents/Helpers/chrome-native-host`, `allowed_origins` includes the extension ID |
| Native host binary | ✅ Present, executable, universal Mach-O |
| Native host process | ✅ Running (`pgrep` finds `chrome-native-host chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/`) |
| Claude Desktop process tree | ✅ Healthy; this Claude Code CLI is a direct child of Claude.app |
| `claude mcp list` (local MCP servers) | ✅ Empty as expected — Chrome MCP tools are provided by Claude Desktop, not user-configured |
| Claude Desktop → Settings → Connectors → "Claude in Chrome [Beta]" | ✅ Enabled toggle on |
| Extension Details (`chrome://extensions`): permissions, native messaging, "On all sites" | ✅ All granted |
| Extension `options.html`: signed-in email matches account | ✅ Match |
| Side-panel agent in Chrome (same extension, same pipe) | ✅ Works — opens tabs, performs searches |
| **Parallel `mcp__Control_Chrome__*` tools** (separate desktop extension) | ✅ **Fully functional** — `list_tabs`, `get_current_tab`, `switch_to_tab` all succeed against the same Chrome |
| `mcp__Claude_in_Chrome__list_connected_browsers` | ❌ "not connected" |
| `mcp__Claude_in_Chrome__switch_browser` | ❌ "not connected" — no pairing prompt appears in extension |

### Expected
- `list_connected_browsers` returns at least one device entry for the running Chrome.
- `switch_browser` triggers a "Connect" prompt inside the Chrome extension.

### Actual
- Both calls return the templated "not connected / often transient" message and never recover.
- The fact that the parallel `Control Chrome` connector works against the same browser proves the issue is not Chrome, the extension, accounts, permissions, or any user-side configuration — it's specifically the in-app relay between the Claude Code session and the `Claude in Chrome` MCP service inside Claude Desktop.

### Ruled out
- Account mismatch (verified same email across CLI + Desktop + extension)
- Extension not installed / not signed in
- Native messaging host missing or misconfigured
- Connector disabled in Desktop settings
- Site permissions ("Your approved sites" being empty wouldn't explain pairing-discovery failure)

### Workaround
Use the `Control Chrome` desktop extension's `mcp__Control_Chrome__*` tools instead — they cover tab/navigation/content operations against the same browser and work reliably.

### Suggested investigation
- Whether the `Claude in Chrome` MCP service inside Claude Desktop registers the running Chrome at startup vs on demand, and whether it picks up extensions installed *after* Desktop launched.
- Whether full Cmd-Q + relaunch of Claude Desktop restores the relay (will test next).

---

please see whats wrong session