[BUG] `mcp__claude-in-chrome__*` tools absent entirely on Windows (MSIX-hosted sessions) — present and working on macOS at identical CLI 2.1.260

### Preflight Checklist

- [x] I have searched existing issues
- [x] This is a single bug report
- [x] I am using the latest version of Claude Code

## Why this is a Claude Code issue, not a Claude Desktop one

Filing here deliberately. Prior reports of this failure were routed away as
"doesn't appear to be about Claude Code" (#58009, bot-closed and locked). Respectfully, the
failing components are Claude Code's:

- The missing tools are **Claude Code MCP tools** (`mcp__claude-in-chrome__*`), absent from a
Claude Code session's tool registry.
- The native-messaging host is **Claude Code's own binary**:
`~/.claude/chrome/chrome-native-host.bat` → `claude.exe --chrome-native-host`.
- The failure is **version-correlated with the Claude Code CLI** (2.1.260), not with a Desktop
feature.

## Summary

On Windows, a Claude Code session hosted by Claude Desktop has **no `mcp__claude-in-chrome__*`
tools at all** — `list_connected_browsers`, `select_browser`, `tabs_context_mcp` are not merely
failing, they are absent from the registry. `ToolSearch` for them returns no match. The server does
not appear in either the "requires authentication" or the "still connecting" lists, so it is not
registering at all.

The **same Claude Code version (2.1.260) on macOS, in the Desktop chat pane, works correctly** and
drives real Chrome profiles.

This is distinct from #91469 / #91485 / #91145, where the tools *exist* and report
"not connected". Here they never appear.

## Environment — controlled A/B

| | Windows (fails) | macOS (works) |
|---|---|---|
| Claude Code CLI | **2.1.260** | **2.1.260** |
| Surface | Desktop chat pane | Desktop chat pane |
| Desktop package | MSIX, `Claude_1.46388.2.0_x64__pzs8sxrjxfjjc`, `CN="Anthropic, PBC"` | PKG |
| Host binary in use | `%APPDATA%\Claude\claude-code\2.1.260\claude.exe` | — |
| Native host manifest `path` | `C:\Users\\.claude\chrome\chrome-native-host.bat` | `/Users//.claude/chrome/chrome-native-host` |
| Extension ID | `fcoeoabgfenejglbffodgkkbkcdhcgfn` | same |
| Extension version | 1.0.90, enabled, no disable reasons | — |
| `mcp__claude-in-chrome__*` | **absent** | present, working |

Both machines: Windows 11 / macOS, same Chrome extension build, same account.

## What has already been eliminated

Please do not close this as a user misconfiguration — the config layer was checked
exhaustively against a known-good Mac:

1. **Native-messaging registry key** — present:
`HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_code_browser_extension`
2. **Manifest → wrapper → binary chain** — intact and resolving end to end.
3. **Wrapper parity** — Windows `.bat` and macOS shell wrapper are the same wrapper in the same
location; **both route to a Claude Code CLI process**, neither to an app bundle.
4. **Extension ID** — identical on both.
5. **Browser registration coverage** — Windows registers 7 browsers (Chrome, Chromium, Edge,
Brave, Arc, Opera, Vivaldi) vs the Mac's 2. The failing machine is a *superset*.
6. **CLI version** — identical, 2.1.260, verified by running-process path (not `PATH`, which
reports an unrelated npm build).
7. **Extension install/enable state** — installed and enabled in the target profile.

## Steps to reproduce

1. Windows 11, Claude Desktop (MSIX) with Claude Code 2.1.260.
2. Install "Claude in Chrome" (1.0.90), sign in, confirm the native host is registered.
3. Open a Claude Code session in the Desktop chat pane.
4. Ask for `list_connected_browsers`, or `ToolSearch` for it.

**Expected:** the tool exists (even if it returns an empty browser roster).
**Actual:** no `mcp__claude-in-chrome__*` tool exists in the session at all.

## Candidate causes (not verified — offered to save triage time)

- **Stale OAuth token cache.** `oauth:tokenCache` and `oauth:tokenCacheV2` are present in
`%APPDATA%\Claude\config.json` on the failing machine. Per #91469, the cache is cleared on `403`
but never on `401`, causing an endless loop. If a failed bridge auth prevents the MCP server from
registering, that would explain absent-vs-erroring tools. **Untested at time of filing.**
- **MSIX / AppContainer.** Windows ships MSIX; macOS ships PKG; the legacy Squirrel `.exe` is
unsandboxed. Fits a Windows-only native-messaging failure. Counter-evidence: the installed package
declares `runFullTrust` and `unvirtualizedResources`.

## Asks

1. **Distinguish "bridge failed to connect/authenticate" from "connected, zero browsers."**
Absent tools give the user nothing to act on. Register the tools and let them return a real
error.
2. **Invalidate the cached token on `401`, not only `403`** (per #91469).
3. **State Windows support explicitly in the docs.** The Chrome docs do not say the integration is
unavailable or degraded on Windows Desktop, so users spend hours on correctly-configured machines.
4. **Please route rather than bot-close.** If this belongs to another team, move it — #58009 was
closed in 3 days and locked in 7, and its technical content was never assessed.

## Prior art — all closed, none fixed

| Issue | Opened | Closed | Outcome |
|---|---|---|---|
| #24539 | 9 Feb 2026 | 13 Feb | `duplicate` |
| #25162 | 12 Feb 2026 | 30 Mar | `bug`, `has repro`, `platform:windows` → **stale** |
| #52766 | 24 Apr 2026 | 27 Apr | `duplicate` |
| #56949 | 7 May 2026 | 10 May | `duplicate` |
| #58009 | 11 May 2026 | 14 May | `invalid` — bot-closed, then locked |
| #58201 | 12 May 2026 | 20 Jul | `bug`, `has repro`, `platform:windows`, `area:chrome` → **stale** |

Two were accepted by triage as reproducible Windows bugs and then auto-closed for inactivity
without a fix. Roughly 15 further Claude-in-Chrome issues were opened in the week before this
filing.

Happy to provide logs, run diagnostics, or test a patch build on the affected machine.

Reproduce the Windows 11 MSIX-hosted session and compare its tool registry with the working macOS session at CLI 2.1.260. Trace the native-messaging chain from the manifest through .claude/chrome/chrome-native-host.bat to claude.exe --chrome-native-host, and inspect config.json token-cache behavior. Done means the browser tools register on Windows and return a clear connection error or browser result.

索引モデルが issue の本文から書いたものです。