[BUG] Microsoft 365 connector unusable in Claude Code (works in Claude Desktop)

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?

The Microsoft 365 connector is enabled on my account and shows as connected in claude.ai connector settings. In Claude Code it registers as an MCP server and then exposes zero tools, so none of its functionality is reachable.

The failure is silent. There is no error, no warning, and no prompt to authorise. The server is simply present with an empty tool list, which makes it look connected and working until you actually try to use it.

Searching the full tool list for Teams, Outlook, mail, calendar, OneDrive and SharePoint returns no matches. Listing MCP resources for the server returns nothing.

The same connector on the same account works correctly in the Claude Desktop app. I ran an identical request there and it read my Microsoft Teams chat with no problem. My nine other connectors all work normally in Claude Code: Google Drive, BigQuery, Meta Ads, Granola, Improvado, Hive, TikTok, Meltwater and Figma. Microsoft 365 is the only one affected.

I found a feature flag in my local config that appears to explain it, included below.

What Should Happen?

Either the connector's tools should be available in Claude Code the way my other connectors are, or Claude Code should clearly report that this connector is not supported on this surface. The current behaviour gives no signal at all, so there is nothing to act on.

Error Messages/Logs

# No error is produced. The server registers with an empty tool list.

# Relevant flag from ~/.claude.json:
"tengu_mcp_local_oauth_blocked_hosts": {
  "hosts": [
    "microsoft365.mcp.claude.com",
    "gmail.mcp.claude.com",
    "gcal.mcp.claude.com"
  ]
}

# cachedGrowthBookFeaturesAt: 2026-09-08T12:22:29 local
# The flag cache is current, not stale.

Steps to Reproduce

1. Enable the Microsoft 365 connector in claude.ai connector settings and confirm it shows as connected.
2. Open Claude Code in the VS Code extension.
3. Ask Claude to read anything from Microsoft 365, for example a Teams chat.
4. Claude reports it has no Microsoft 365 tools available.
5. Search the session tool list for Teams, Outlook, mail, calendar, OneDrive or SharePoint. No matches.
6. Run the same request in the Claude Desktop app on the same account. It succeeds.

Things I tried that made no difference:

• Restarting Claude Code
• Quitting and restarting VS Code entirely
• Starting a fresh session rather than resuming an existing one
• Reconfirming the connector was connected in claude.ai settings

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code VS Code extension 2.1.263 (darwin-arm64)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

The flag name suggests local OAuth is blocked for those three hosts, which would explain a server that registers but never authorizes and so advertises no tools. I did not set this flag and I understand it is delivered remotely. I am not asking to change it myself.

The three blocked hosts are Microsoft 365, Gmail and Google Calendar. If this is a deliberate policy for these connectors in Claude Code, please confirm that, and consider surfacing it in the UI. The connector currently reads as connected in settings, and I spent a lot of time restarting VS Code and re-authorizing before finding the flag.

If it is deliberate, knowing whether support is planned would help. That determines whether I build a workaround or wait.