[BUG] macOS Cowork: Claude in Chrome shows INCLUDED but sessions receive zero browser tools — regression starting ~April 10

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Cowork sessions launch with zero browser tools despite Claude in Chrome being properly installed, enabled, and showing as INCLUDED under Desktop connectors. No browser tools (navigate, click, read_page, screenshot, tabs_context_mcp, etc.) are registered in the session at all. When asked to perform any browser task, the session searches the connector registry, finds nothing, and reports it has no browser capability.
This was working correctly until approximately April 10, 2026. Chrome still has tab groups from prior successful Claude-controlled browser sessions, confirming the integration was functional before.

What Should Happen?

New Cowork sessions should detect the Claude in Chrome extension via the native messaging host and register browser tools (navigate, click, read_page, screenshot, tabs_context_mcp, etc.) so the session can control Chrome for browser-based tasks. This is how it worked prior to ~April 10.

Error Messages/Logs

No explicit error messages. The failure is silent — browser tools simply never appear in the session's available tools. When the session attempts to find browser capability, it reports:
"I don't currently have that connection available in this session."
"Connector search: 0 connectors found"
"There's no Chrome browser connector available in the registry right now."

Steps to Reproduce

STEPS TO REPRODUCE:

Verify Claude in Chrome extension v1.0.66 is installed and enabled in chrome://extensions
Verify native messaging host config exists at ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_code_browser_extension.json with correct contents (path pointing to /Applications/Claude.app/Contents/Helpers/chrome-native-host, extension ID in allowed_origins)
Verify the binary at /Applications/Claude.app/Contents/Helpers/chrome-native-host exists and is executable
Open Claude Desktop, confirm "Claude in Chrome" shows as INCLUDED under Desktop → Connectors
Quit Chrome (Cmd+Q) and Claude Desktop (Cmd+Q) completely
Reopen Chrome, then Claude Desktop
Start a new Cowork session
Ask: "navigate to example.com"
Session reports no browser tools available

Verified that all of the following are correct and none resolve the issue:

Native messaging host JSON exists with correct path and extension ID (fcoeoabgfenejglbffodgkkbkcdhcgfn) in allowed_origins
Binary exists and is executable (last modified April 10)
Extension is ON with all permissions including "Communicate with cooperating native applications" and site access "On all sites"
Service worker and offscreen.html both running
No error badges on extension in Developer mode
Complete extension uninstall + reinstall from Chrome Web Store does not fix it
Multiple full restart cycles of both Chrome and Claude Desktop do not fix it

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown exact version number. Last working approximately April ~10, 2026 — the same date the chrome-native-host binary was last modified, suggesting a Claude Desktop update that day.

Claude Code Version

2.1.104 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Why this is a new issue — reviewed related reports:

#44541 (Chrome connection not possible with Cowork, closed April 10 as duplicate) — That issue reported tabs_context_mcp calls returning "Chrome extension isn't reachable" errors, meaning browser tools were present but failing. In my case, zero tools are ever registered in the session. There is nothing to call.
#46869 (Extension connects in Desktop but not terminal CLI) — Opposite problem. That user's Desktop/Cowork works; only their terminal CLI is broken.
#38783 (Windows: browser tools missing after update) — Same symptom class but Windows. That user saw tools drop from 19 to 3. I see a drop from full functionality to 0.
#46487 (Cowork VM connection timeout, Windows) — Different platform, different failure mode (VM won't connect vs. VM works but lacks browser tools).
#39011 (URL parsing failure after reconnection, macOS) — Mid-session reconnection issue. My issue is present from the very start of every new session.

Additional observations:

The native messaging host JSON file was found missing on April 12 before being regenerated (likely by a prior troubleshooting attempt or app restart). Even after full restoration of all components, the issue persists.
Chrome retains tab groups from prior successful Claude browser sessions, proving the extension and native messaging pipeline were functional before the regression.
The chrome-native-host binary's last-modified date of April 10 aligns with when the integration stopped working, suggesting a Claude Desktop update touched this file.

Hypothesis: The April 10 Claude Desktop update may have disrupted the handshake between Cowork session initialization and the Chrome extension bridge. Possibly related to the "server-side stale state" root cause identified in #44541, but manifesting as total tool absence rather than connection errors on existing tools.