gws-mcp-server

gws-mcp-server

Google Workspace for AI agents: Gmail, Calendar, Drive, Sheets, Docs, and Tasks as a curated set of 39 Model Context Protocol tools, built on the official Google Workspace CLI (gws).

Why?

The gws CLI had a built-in MCP server that was removed in v0.8.0 because it exposed 200-400 tools — causing context window bloat in MCP clients. This server takes a curated approach: you choose which Google services to expose, and only a focused set of high-value, narrowly scoped operations are registered as tools. Every tool declares MCP readOnlyHint/destructiveHint annotations so clients can reason about side effects and surface clearer consent prompts.

Prerequisites

• Node.js 18+
• gws CLI installed and authenticated (npm install -g @googleworkspace/cli && gws auth login)

Quick start

# Install
npm install -g gws-mcp-server

# Or run from source
git clone https://github.com/conorbronsdon/gws-mcp-server.git
cd gws-mcp-server
npm install && npm run build

Configuration

Claude Code (.mcp.json)

{
  "mcpServers": {
    "google-workspace": {
      "command": "npx",
      "args": [
        "gws-mcp-server",
        "--services", "drive,sheets,calendar,docs,gmail,tasks"
      ]
    }
  }
}

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "google-workspace": {
      "command": "npx",
      "args": [
        "gws-mcp-server",
        "--services", "drive,sheets,calendar"
      ]
    }
  }
}

Options

Flag	Description	Default
--services, -s	Comma-separated list of services to expose	All services
--gws-path	Path to the gws binary	gws

Available services & tools

drive (9 tools)

• drive_files_list — Search and list files
• drive_files_get — Get file metadata
• drive_files_create — Create files (with optional upload)
• drive_files_copy — Copy files (useful for format conversion)
• drive_files_update — Update file metadata/content
• drive_files_delete — Delete files
• drive_files_export — Export Google Workspace files (Doc, Sheet, Slide) to other formats
• drive_files_download — Download file content (text inline, binary as base64 or saved to a path; Google-native files are exported to a readable format)
• drive_permissions_create — Share files

sheets (4 tools)

• sheets_get — Get spreadsheet metadata
• sheets_values_get — Read cell values
• sheets_values_update — Write cell values
• sheets_values_append — Append rows

calendar (5 tools)

• calendar_events_list — List events
• calendar_events_get — Get event details
• calendar_events_insert — Create events
• calendar_events_update — Update events (only supplied fields change)
• calendar_events_delete — Delete events

docs (3 tools)

• docs_get — Get document content
• docs_create — Create documents
• docs_batchUpdate — Apply document updates

gmail (6 tools)

• gmail_messages_list — Search messages
• gmail_messages_get — Read a message
• gmail_threads_list — Search threads
• gmail_threads_get — Read a full thread
• gmail_threads_modify — Add/remove labels on a thread (archive, mark read, star)
• gmail_drafts_create — Create a draft (plain text and/or HTML, with reply threading via threadId). Drafts are never auto-sent

tasks (12 tools)

• tasks_tasklists_list — List task lists
• tasks_tasklists_get — Get a task list
• tasks_tasklists_insert — Create a task list
• tasks_tasklists_update — Update a task list (only supplied fields change)
• tasks_tasklists_delete — Delete a task list
• tasks_tasks_list — List tasks (filters: completed/hidden/due dates)
• tasks_tasks_get — Get a task
• tasks_tasks_insert — Create a task (optionally nested or positioned)
• tasks_tasks_update — Update a task (only supplied fields change; common use: mark complete)
• tasks_tasks_move — Move a task within/across lists or reorder
• tasks_tasks_delete — Delete a task
• tasks_tasks_clear — Hide all completed tasks in a list

Update semantics: the *_update tools (calendar events, tasks, task lists) use the Google API's patch verb — they merge the fields you supply and leave the rest untouched. To clear an existing value, pass it explicitly (e.g. an empty string) rather than omitting it.

Total: 39 tools (vs 200-400 in the old implementation)

Adding new tools

Edit src/services.ts to add tool definitions. Each tool maps directly to a gws CLI command:

{
  name: "drive_files_list",           // MCP tool name
  description: "List files in Drive", // Shown to AI
  command: ["drive", "files", "list"],// gws CLI args
  params: [                           // Maps to --params JSON
    { name: "q", description: "Search query", type: "string", required: false },
  ],
  bodyParams: [                       // Maps to --json body
    { name: "name", description: "File name", type: "string", required: true },
  ],
}

Typed errors

Tool call failures are mapped to a typed error hierarchy (src/errors.ts): AuthenticationError (401/403), RateLimitError (429), ValidationError (400), NotFoundError (404, with a shared-drive access hint for drive commands), and ServerError (5xx), all extending a base GwsError. Unlike an HTTP API client, this server has no response object to read a status code from — it spawns the gws CLI as a subprocess and only sees plain text (stdout/stderr, or a rejected promise's .message). mapGwsErrorToTyped() recovers a status-like code from that text, handling both a raw JSON error body (Google's own {"error":{"code":...,"message":...}} shape) and plain text containing an HTTP-status-like token (e.g. "Error 404: ..."). If neither pattern is found, the original message passes through unchanged rather than forcing an invented status onto it.

Architecture

MCP Client (Claude) ←→ stdio ←→ gws-mcp-server ←→ gws CLI ←→ Google APIs

The server is a thin wrapper: it translates MCP tool calls into gws CLI invocations, passes --params and --json as appropriate, and returns the JSON output. Authentication stays in the gws CLI — this server never sees or stores your Google credentials.

Development

git clone https://github.com/conorbronsdon/gws-mcp-server.git
cd gws-mcp-server
npm ci
npm run lint    # type-check
npm run build
npm test        # vitest, mocks the executor layer — no real gws calls

Contributing

Issues and pull requests are welcome. The most useful contributions are new tool definitions in src/services.ts for high-value gws operations (see "Adding new tools" above). Keep the curated contract: a focused set of narrowly scoped tools, not a 1:1 mirror of every Google API surface. See SECURITY.md for how to report vulnerabilities.

About

Built and maintained by Conor Bronsdon. I host the Chain of Thought podcast, which covers AI infrastructure, developer tools, and how practitioners actually use this stuff. I built this to give the agent workflows that run the show safe, curated access to Gmail, Calendar, Drive, Sheets, Docs, and Tasks.

Companion tools:

• Transistor-MCP: the Transistor.fm MCP server. Episodes, transcripts, and download counts.
• substack-mcp: read posts and manage drafts on Substack, safe for agent workflows.
• podcastindex-mcp: the Podcast Index MCP server, search by person or topic, trending shows, feed health.
• op3-mcp: podcast analytics through OP3. Downloads, geography, apps. Read-only.
• ai-tools-for-creators: a curated list of AI skills and MCP servers for people who ship ideas for a living.

More at chainofthought.show and on X.

Disclaimer

All views, opinions, and statements expressed on this account are solely my own and are made in my personal capacity. They do not reflect, and should not be construed as reflecting, the views, positions, or policies of Modular. This account is not affiliated with, authorized by, or endorsed by Modular in any way.

License

MIT