Google Sheets MCP

An MCP server for MCP Studio (or any MCP-compatible host) that lets an agent create, read, and modify Google Sheets. Auth is a Google service account — no OAuth dance, no client secret, no app-verification process.

Typical use:

"Look at Hacker News, then create a Google Sheet called Top Stories with the top 10 stories. Send me the link."

The agent uses a browser MCP (like Chrome) to scrape, then this MCP's create_sheet + append_rows, and replies with the spreadsheet URL.

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Tools

Tool	What it does
create_sheet(title, headers?, share_with_email?)	Creates a new spreadsheet; optionally writes a header row and shares it with an email as writer. Returns spreadsheet_id + url.
append_rows(spreadsheet_id, values, sheet_name?)	Appends rows to the bottom of a tab. values is a 2D array of cell values.
update_range(spreadsheet_id, range, values)	Overwrites an A1-notation range like Sheet1!A1:C3.
read_range(spreadsheet_id, range)	Reads an A1 range and returns the values as JSON.

Quick commands

Trigger	Action
/sheet_create <title>	Create a new sheet with the given title.
/sheet_read	Read A1:Z100 from the most recently created sheet.

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Setup — one-time, ~5 minutes

You need a Google service account so this MCP can talk to the Sheets API on your behalf.

1. Create a Google Cloud project (skip if you already have one): https://console.cloud.google.com/projectcreate

2. Enable two APIs in that project:

   • Google Sheets API
   • Google Drive API — needed so the MCP can share created sheets with you.

3. Create a service account:

   • Go to https://console.cloud.google.com/iam-admin/serviceaccounts
   • Click Create service account.
   • Give it any name (e.g. mcp-sheets), skip the optional role/access steps, click Done.

4. Generate a JSON key:

   • Open the service account you just made → Keys tab → Add key → Create new key → JSON.
   • A .json file downloads. Keep it handy; you'll paste its full contents into MCP Studio in the next step.

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Install in MCP Studio

From the MCP Studio prompt panel:

/install https://github.com/RPieterse/mcp-studio-google-sheets-mcp

…or install from a local clone:

/install /path/to/mcp-studio-google-sheets-mcp

Studio will then prompt for two fields:

Field	What to paste
Service account JSON	The entire contents of the JSON key file from step 4.
Your Google email	The Google account address that newly-created sheets will be shared with as a writer (so they show up in your Drive).

That's it. Test it from the panel:

/sheet_create my first MCP-created sheet

…or just say "create a new Google Sheet called inbox" to your agent.

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How ownership works

Service accounts are separate Google identities, so:

• Sheets are owned by the service account, not by you.
• They are automatically shared with you (using the email from install) as a writer. You'll see them under "Shared with me" in Drive — drag to My Drive if you want them mixed with your own files.
• If you need this MCP to write to a sheet you already own, share that sheet with the service account's client_email (visible in the JSON key file).
• Quota counts against the service account's project, not your personal Google account.

If you want sheets owned by your account directly, that requires OAuth instead of a service account — see Future work below.

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Local development

git clone https://github.com/RPieterse/mcp-studio-google-sheets-mcp.git
cd mcp-studio-google-sheets-mcp
npm install
npm run build
npm test

To iterate against Studio without reinstalling, run a watcher in one terminal:

npx tsc --watch

Studio re-reads the manifest and respawns the server on each tool call, so saved code is picked up live. Manifest edits are picked up on the next /mcp-servers call.

Project layout

src/
  index.ts        Stdio entrypoint. Reads env, builds the API client, wires the server.
  server.ts       MCP tool schema + dispatch.
  tools.ts        Pure handler functions (no Google deps — testable with a mock SheetsApi).
  sheets.ts       Real googleapis-backed SheetsApi implementation.
  credentials.ts  Parses + validates the service account JSON.
  types.ts        Shared types + the SheetsApi interface.
test/             vitest unit tests against the mock API.
widget.manifest.json    MCP Studio manifest.

Tests

npm test runs the vitest suite. Tools and credential parsing are covered against an in-memory mock SheetsApi; no Google account or network is touched.

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Permissions declared

network: sheets.googleapis.com, www.googleapis.com, oauth2.googleapis.com
secrets: gsheets_credentials

No filesystem access. The service account JSON never leaves the OS keychain; this MCP only sees it via process.env at spawn time.

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Future work

• OAuth flow for user-owned sheets (requires Studio's OAuth implementation to support client_secret, which Google's Desktop OAuth requires even with PKCE — pending an upstream change to MCP Studio).
• Batch update tool (batch_update_range) for multi-range writes in one API call.
• Sheet/tab management — add new tabs, rename, delete.
• Formatting — bold headers, freeze first row, etc.

PRs welcome.

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License

MIT.