Google Workspace MCP on OpenClaw — 54 Tools, Authentication, and Encryption Pitfalls

Google Workspace MCP is now operational on OpenClaw.

Gmail, Calendar, Drive, Docs, Sheets, Slides, Chat, People. 54 tools accessible from an AI agent.

This documents the process of running gemini-cli-extensions/workspace on OpenClaw via mcporter — authentication flows, encryption formats, salt fixation, and every technical pitfall encountered.

What is Google Workspace MCP

gemini-cli-extensions/workspace is Google’s MCP implementation.

MCP (Model Context Protocol) is a standard protocol for AI models to use external tools, created by Anthropic.

This server, built for Gemini CLI, exposes major Google Workspace services as 54 tools:

The problem: it was designed exclusively for Gemini CLI. Not usable with other AI tools.

OpenClaw has its own MCP implementation. mcporter, a proxy server, connects arbitrary MCP servers.

That’s why making it work was the goal.

Running on OpenClaw + mcporter

OpenClaw implements the MCP standard independently.

mcporter’s role:

1. Start an MCP server (stdio mode)
2. Translate process I/O to HTTP API
3. Make it callable from OpenClaw via HTTP

Configuration file at ~/.openclaw/mcp-servers.json:

{
  "google-workspace": {
    "command": "node",
    "args": ["/home/flock_h/gws-extension/dist/index.js"],
    "env": {
      "NODE_ENV": "production"
    }
  }
}

Launch:

mcporter start google-workspace

This should make tools available from OpenClaw via mcporter:google-workspace.

Authentication Flow: Hybrid Flow, localhost, and Manual Mode

Google Workspace APIs require OAuth2 authentication.

gemini-cli-extensions/workspace supports three auth flows:

1. Hybrid Flow via Cloud Function (Recommended)

A Cloud Function on Google’s shared GCP project exchanges authorization codes for tokens.

Advantages:

• No client_secret stored locally
• Uses a Gemini CLI-specific GCP project

Flow:

1. Open auth URL in browser
2. After approval, Cloud Function issues tokens
3. Tokens saved to file

2. Localhost Callback Flow

Standard OAuth2 flow with a local HTTP server receiving the redirect.

Limitation:

• Remote environments (like GCE) have no browser
• Requires port forwarding

3. Manual Mode

Copy-paste the authorization code manually.

node dist/index.js auth --manual

For GCE environments, this is the most reliable option.

Pitfall 1: Token File Encryption Format

Authentication succeeded. Token file was generated.

But server startup produced “Token file corrupted.”

[ERROR] Token file corrupted or invalid master key

Debugging with the –debug Flag

Adding --debug produces detailed logs:

node dist/index.js serve --debug

Log file: gws-extension/logs/server.log

Found the issue:

[DEBUG] Decryption failed: Unsupported state or unable to authenticate data

The encryption format was wrong.

AES-256-GCM vs AES-256-CBC

This MCP server encrypts tokens using AES-256-GCM.

GCM (Galois/Counter Mode): Encryption + authentication tag as a unit. Detects data tampering.

Format:

iv:authTag:encryptedData

Three parts, colon-separated.

Initially saved as CBC format: iv:encryptedData — only two parts. Missing the authTag.

Decoding therefore failed.

Fix

Include the authTag when saving tokens:

const cipher = crypto.createCipheriv('aes-256-gcm', key, iv);
const encrypted = Buffer.concat([cipher.update(text, 'utf8'), cipher.final()]);
const authTag = cipher.getAuthTag();

// Save as iv:authTag:encrypted format
const combined = `${iv.toString('hex')}:${authTag.toString('hex')}:${encrypted.toString('hex')}`;

Decryption now works correctly.

Pitfall 2: Salt Fixation (Hostname Dependency)

The encryption key derivation uses a salt.

Default salt includes hostname:

const salt = `${os.hostname()}-${os.userInfo().username}-gemini-cli-workspace`;

Problem: In Docker containers, hostname changes on every restart.

Each container restart changes the encryption key, making existing token files undecryptable.

Solution: Fix the Salt

Made the salt overridable via environment variable:

const salt = process.env.GWS_SALT || `${os.hostname()}-${os.userInfo().username}-gemini-cli-workspace`;

For GCE environments:

export GWS_SALT="yureichan-flock_h-gemini-cli-workspace"

Tokens now survive restarts.

Result: 54 Tools Available

Authentication resolved, encryption fixed.

Google Workspace MCP is callable from OpenClaw.

mcporter list-tools google-workspace

Output (partial):

gmail_list_messages
gmail_search_messages
gmail_send_message
calendar_list_events
calendar_create_event
drive_list_files
drive_search_files
docs_create_document
sheets_read_spreadsheet
slides_create_presentation
...

54 tools. Every major Google Workspace service accessible from the AI agent.

Automation via Heartbeat

OpenClaw has a heartbeat feature — periodically asking the agent “anything to check?”

Define periodic checks in HEARTBEAT.md:

# Heartbeat Checklist

## Email Check (2x/day)
- Check for unread important emails
- Use mcporter:google-workspace/gmail_list_messages

## Calendar Check (2x/day)
- Review today's and tomorrow's events
- Use mcporter:google-workspace/calendar_list_events

The AI agent now automatically monitors email and calendar.

Summary

Google Workspace is now operational on OpenClaw.

Authentication via manual mode, tokens encrypted with AES-256-GCM, salt fixed via environment variable.

Debug flag enabled root cause identification, resolved one issue at a time.

54 tools. The AI agent can now operate across your entire Google Workspace.