Hardened Google Workspace MCP

A security-hardened Google Workspace integration for Claude Code.

This is a fork of taylorwilsdon/google_workspace_mcp with dangerous operations removed to prevent data exfiltration via prompt injection attacks. See SECURITY.md for details.

What This Does

Enables Claude Code to interact with your Google Workspace:

Gmail: Read emails, create drafts (cannot send)
Google Drive: Read/create files (cannot share externally)
Google Docs: Read and edit documents
Google Sheets: Read and write spreadsheets
Google Calendar: View and create events
Google Forms: Read and create forms
Google Slides: Read and edit presentations

Why "Hardened"?

LLMs are vulnerable to prompt injection attacks—malicious instructions hidden in content the model processes. An attacker could embed instructions in an email or document that trick the AI into exfiltrating sensitive data.

This fork removes all tools that could send data outside your account:

No email sending - Claude can draft emails, but you must manually send them from Gmail
No file sharing - Claude cannot share files with external users
No filter creation - Claude cannot create auto-forwarding rules
Secure credential storage - OAuth tokens stored in macOS Keychain, not plaintext files

See SECURITY.md for the complete security model.

Prerequisites

Claude Code installed on your machine
A Google Workspace or personal Google account
Python 3.11+ installed

Quick Start

Step 1: Create OAuth Credentials

Follow OAUTH_SETUP.md to create Google Cloud OAuth credentials.

Step 2: Install Dependencies

cd ~/hardened-google-workspace-mcp  # or wherever you placed it
uv sync

Note: If you don't have uv installed, run: curl -LsSf https://astral.sh/uv/install.sh | sh

Step 3: Configure Claude Code

Add the MCP server using claude mcp add:

claude mcp add hardened-workspace \
  --scope user \
  -e GOOGLE_OAUTH_CLIENT_ID="YOUR_CLIENT_ID" \
  -e GOOGLE_OAUTH_CLIENT_SECRET="YOUR_CLIENT_SECRET" \
  -- uv run --directory ~/hardened-google-workspace-mcp python -m main --single-user

Replace YOUR_CLIENT_ID and YOUR_CLIENT_SECRET with your OAuth credentials.

Or manually add to ~/.claude/mcp_config.json:

{
  "mcpServers": {
    "hardened-workspace": {
      "command": "uv",
      "args": ["run", "--directory", "/Users/YOUR_USERNAME/hardened-google-workspace-mcp", "python", "-m", "main", "--single-user"],
      "env": {
        "GOOGLE_OAUTH_CLIENT_ID": "YOUR_CLIENT_ID",
        "GOOGLE_OAUTH_CLIENT_SECRET": "YOUR_CLIENT_SECRET"
      }
    }
  }
}

Step 4: Authorize with Google

Start (or restart) Claude Code
The first time you use a Google Workspace tool, a browser window will open
Sign in with your Google account
Click "Allow" to grant permissions

For detailed instructions, see SETUP.md.

Example Prompts

Once set up, try these prompts in Claude Code:

List my recent emails from the past week

Read the document "Q4 Planning" from my Google Drive

Create a draft email to john@example.com about the meeting tomorrow

Show me what's on my calendar for next Monday

Update cell A1 in my "Budget 2025" spreadsheet to "Updated"

Troubleshooting

"OAuth credentials not found"

Make sure you've set the GOOGLE_OAUTH_CLIENT_ID and GOOGLE_OAUTH_CLIENT_SECRET environment variables in your MCP config.

"Permission denied" errors

Delete the credentials folder: rm -rf ~/.credentials/workspace-mcp/
Restart Claude Code
Re-authorize with your Google account

"Tool not found" errors

Make sure the MCP server is running. Check Claude Code's MCP status panel.

Browser doesn't open for authorization

If the browser doesn't open automatically, check the Claude Code output for a URL to copy/paste manually.

Security Notes

Never disable permission prompts - Always review what Claude is asking to do
Drafts require manual sending - Claude can create email drafts, but you must open Gmail to send them
No external sharing - Claude cannot share files outside your organization
Report issues - If Claude behaves unexpectedly, file an issue

See SECURITY.md for comprehensive security documentation.

Support

For issues with this project, please file an issue on GitHub.

Based on google_workspace_mcp by Taylor Wilsdon, licensed under MIT.

hardened-google-workspace-mcp