MCP Google Sheets

An MCP (Model Context Protocol) server that gives AI agents read/write access to Google Spreadsheets. Built for use with Claude Code and other MCP-compatible clients.

Features

• 9 tools for spreadsheet interaction — read metadata, read cells, extract schemas, create/rename tabs, append rows, insert columns, set column validation, update rows

• Per-user OAuth (recommended) — each user signs in with their own Google account; sheet edit history shows who actually made each change

• Service Account auth (legacy) — fully headless, no OAuth popups

• No fixed spreadsheet — every tool takes a spreadsheet parameter (paste a Sheets URL or ID); any sheet the signed-in user can edit just works

• Tool filtering — expose only the tools you need via the TOOLS variable

• Audit trail — optionally stamp each written row with a user name

Related MCP server: google-sheets-mcp

Available Tools

Every tool takes a required spreadsheet parameter: a full Google Sheets URL (https://docs.google.com/spreadsheets/d/<ID>/edit...) or a bare spreadsheet ID.

Install

If you use Claude Code, add the server with one command. You need an OAuth Client ID and Client Secret — ask whoever set up your team's Google Cloud project, or create them yourself via OAuth Setup below.

claude mcp add \
  --scope user \
  --env GOOGLE_OAUTH_CLIENT_ID=<your-client-id>.apps.googleusercontent.com \
  --env GOOGLE_OAUTH_CLIENT_SECRET=<your-client-secret> \
  --transport stdio \
  google-sheets \
  -- npx -y @toantran201/mcp-google-sheets

On Windows PowerShell, put it on a single line (drop the \ line breaks), or replace \ with a backtick `.

• --scope user makes the server available in all your projects. Use --scope project instead to write it into a shared .mcp.json (checked into the repo for your whole team), or omit --scope for the current project only.

• --transport stdio is the default; it's shown here mainly so the server name doesn't sit directly after --env (the CLI rejects that).

That's it. On the first tool call, your browser opens for Google sign-in; your personal token is cached at ~/.google-sheets-mcp/tokens.json. There is no fixed spreadsheet — just paste a Google Sheets URL into the conversation.

Add this to your .mcp.json (Claude Code) or your client's MCP config:

{
  "mcpServers": {
    "google-sheets": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@toantran201/mcp-google-sheets"],
      "env": {
        "GOOGLE_OAUTH_CLIENT_ID": "xxxxx.apps.googleusercontent.com",
        "GOOGLE_OAUTH_CLIENT_SECRET": "GOCSPX-xxxxx"
      }
    }
  }
}

Optional env keys: TOOLS (comma-separated allowlist, blank = all — see Restricting Tools), USER_NAME (stamped onto add_rows writes). Pin a version with @toantran201/mcp-google-sheets@1.2.3.

Prerequisites

• Node.js 20+ (only needed locally; npx handles it automatically)

• A Google Cloud project with the Sheets API enabled

• OAuth client credentials (recommended) or a Google Service Account

OAuth Setup (recommended — one-time, per team)

With OAuth, each team member authenticates with their own Google account. Edits show up under their name in the sheet's version history, and they can access any sheet they already have permission on — no sharing to a robot account needed.

1. Create a Google Cloud Project

1. Go to Google Cloud Console

2. Click the project dropdown at the top and select New Project

3. Give it a name (e.g. mcp-sheets) and click Create

2. Enable the Google Sheets API

1. Go to APIs & Services > Library

2. Find Google Sheets API and click Enable

3. Configure the OAuth Consent Screen

1. Go to APIs & Services > OAuth consent screen

2. Choose the user type:

   • Internal (available if your team uses Google Workspace) — recommended. No verification needed, refresh tokens never expire, and only members of your organization can sign in.

   • External — works with any Google account, but while the app is in Testing status you must add each teammate as a test user, and refresh tokens expire every 7 days (the server detects this and simply re-opens the browser to sign in again).

3. Fill in the app name and contact emails, save

4. Create an OAuth Client ID

1. Go to APIs & Services > Credentials

2. Click + CREATE CREDENTIALS > OAuth client ID

3. Application type: Desktop app

4. Copy the Client ID and Client Secret. Supply them via your MCP client's env config — the --env flags in the Install command, or the env block in .mcp.json. (Only when developing locally do you put them in a .env file — see Local development.)

Per Google's documentation, a Desktop-app client secret is not treated as a confidential secret (installed apps can't keep secrets). It's fine to share it within your team, but keep it out of version control — don't commit a .env or a checked-in .mcp.json that contains it.

First run

The first time any tool is called, the server opens your browser for Google sign-in. After you approve, tokens are cached at ~/.google-sheets-mcp/tokens.json and later runs are silent. To switch Google accounts, delete that file.

Changing TOOLS from a read-only set to one that includes write tools requires a broader OAuth scope — the server detects this and re-prompts in the browser once.

Security notes

• The sign-in flow uses the OAuth installed-app pattern with PKCE (S256) and a CSRF state check; the loopback server binds only to 127.0.0.1 on an ephemeral port.

• The refresh token is cached in plaintext at ~/.google-sheets-mcp/tokens.json, protected by file permissions (0600, directory 0700; on Windows, your profile's NTFS ACLs). This is the same model used by gcloud and gh. Any process running as your OS user can read it — treat your user account as the trust boundary, and delete the file to revoke local access.

• The OAuth client secret is never written to disk by the server; it comes from the environment your MCP client passes in (the env config), or from .env during local development.

• All cell writes are sanitized against formula/CSV injection (leading =, +, -, @, tab, CR are neutralized with a ' prefix).

Service Account Setup (legacy alternative)

Headless auth with a shared robot account. Edits are attributed to the service account, not individual users, and every target sheet must be shared with it.

1. Create a Service Account

1. In your Google Cloud project (Sheets API enabled), go to APIs & Services > Credentials

2. Click + CREATE CREDENTIALS > Service account

3. Enter a name (e.g. mcp-agent) and click Create and Continue, then Done

4. Note the email address (e.g. mcp-agent@mcp-sheets.iam.gserviceaccount.com)

2. Generate a Private Key

1. Click on the service account, go to the Keys tab

2. Click Add Key > Create new key, select JSON, click Create

3. From the downloaded JSON: client_email → GOOGLE_SERVICE_ACCOUNT_EMAIL, private_key → GOOGLE_PRIVATE_KEY

3. Share Your Spreadsheet

1. Open the Google Sheet, click Share

2. Paste the service account email

3. Set the role to Editor (Viewer is enough for read-only tools)

Tip: The private key from the JSON file contains literal \n characters. Paste it as-is — the server handles the conversion.

Local development

Clone and install only if you want to modify the server:

git clone <repo-url>
cd google-sheets-mcp
npm install
cp .env.example .env   # fill in ONE auth mode below

# Mode A (recommended): per-user OAuth
GOOGLE_OAUTH_CLIENT_ID="xxxxx.apps.googleusercontent.com"
GOOGLE_OAUTH_CLIENT_SECRET="GOCSPX-xxxxx"

# Mode B (legacy): service account
# GOOGLE_SERVICE_ACCOUNT_EMAIL="mcp-agent@your-project.iam.gserviceaccount.com"
# GOOGLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\nMIIEv...\n-----END PRIVATE KEY-----\n"

# Optional — comma-separated list of tools to expose (blank = all)
TOOLS=""

# Optional — name appended to each row written by add_rows
USER_NAME=""

If both modes are configured, OAuth wins. There is no SPREADSHEET_ID — just paste a sheet link into your conversation and the agent passes it to the tools.

npm run dev      # run from TypeScript, no build
npm run build    # bundle to dist/index.js
npm start        # run the built server

Point .mcp.json at your local checkout while developing:

{
  "mcpServers": {
    "google-sheets": {
      "type": "stdio",
      "command": "npx",
      "args": ["tsx", "/absolute/path/to/google-sheets-mcp/src/index.ts"]
    }
  }
}

Publishing a new version

Maintainers only. The package is public on npm under the @toantran201 scope.

npm login                      # once per machine; sign in as the scope owner (toantran201)
npm version patch              # or minor / major — bumps package.json + git tag
npm publish                    # prepublishOnly runs the build automatically
git push --follow-tags

files in package.json limits the tarball to dist/ (plus README + LICENSE) — source, .env, and docs are never published. Verify with npm pack --dry-run before publishing.

Restricting Tools

Use the TOOLS environment variable to expose only specific tools. This reduces token usage when the agent doesn't need all capabilities, and in OAuth mode a read-only tool set requests the narrower read-only scope.

# Read-only mode
TOOLS=get_spreadsheet_info,get_sheet_data

# Write-only (no reads)
TOOLS=add_rows,update_row

# All tools (default)
TOOLS=

Project Structure

src/
  index.ts              Server bootstrap & stdio transport
  config.ts             Env var loading, auth-mode detection & validation
  sheets-client.ts      Google Sheets API wrapper (per-call spreadsheet ID)
  spreadsheet-ref.ts    Spreadsheet URL/ID parsing
  auth/
    auth-manager.ts     Auth entry point (OAuth or Service Account)
    oauth-flow.ts       Browser loopback sign-in flow
    token-store.ts      Per-user token cache (~/.google-sheets-mcp/)
    scopes.ts           Read-only vs read/write scope resolution
  tools/
    index.ts            Tool registry & TOOLS filter
    shared/             Non-tool helpers shared across tools
      types.ts          Shared ToolDefinition interface
      sanitize.ts       Formula-injection guard for cell writes
      result.ts         CallToolResult factory (success/error shapes)
    get-spreadsheet-info.ts
    get-sheet-schema.ts
    get-sheet-data.ts
    find-rows.ts
    create-sheet.ts
    rename-sheet.ts
    add-rows.ts
    add-columns.ts
    update-row.ts
    delete-rows.ts

License

MIT