What is google-mcp-server CLAUDE.md?

Repository instructions for developing a Go-based MCP server that connects AI agents to Google Calendar, Drive, Gmail, Sheets, and Docs through OAuth 2.0.

Use them when modifying, testing, or reviewing this Google API integration project.

They define safe testing and coding practices, including using the server interface rather than writing separate programs to call Google APIs.

How ngs/google-mcp-server configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to ngs/google-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/ngs/google-mcp-server/master/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/ngs/google-mcp-server

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

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Your own site

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Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

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Per session 2,148 This file is loaded in full into every session.

When invoked 2,148 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.02148	$0.02148
Opus 5.5	$0.00859	$0.00859
Sonnet 5.5	$0.00430	$0.00430
Haiku 4.5	$0.00215	$0.00215

Measured 1mo ago against content hash f66bae10ec79, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

google-mcp-server CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 245 lines

How it starts

The opening of the file, as written. The whole thing — 245 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Claude Code Instructions for Google MCP Server

This document contains specific instructions for Claude Code when working with the Google MCP Server project.

Project Overview

This is a Go-based MCP (Model Context Protocol) server that integrates with Google APIs including Calendar, Drive, Gmail, Sheets, and Docs. The server uses OAuth 2.0 for authentication and provides tools and resources accessible through MCP-compatible clients.

Development Guidelines

Important Rules

NEVER create test scripts or demo scripts - Testing should be done through the MCP interface or existing tools
DO NOT create standalone test programs - Use the MCP server directly for testing functionality
AVOID creating example/demo files - The MCP server itself is the interface for testing
NEVER write Go programs to call Google APIs directly - Always use MCP tools or existing server functionality
DO NOT create any executable programs - If MCP tools are unavailable, investigate why and report the issue instead

Code Style

Use Go idioms and best practices
Follow the existing code structure and patterns
Keep functions focused and single-purpose
Use meaningful variable and function names
Add error handling for all API calls

Testing

Before committing any changes, always run:

go test ./...
go fmt ./...

Building

To build the project:

go build -o google-mcp-server .

Service Implementation Status

Fully Implemented with Multi-Account Support

Calendar Service (calendar/): All 8 tools + multi-account support via calendar/multi_account.go
Drive Service (drive/): All 23 tools including Markdown and comment support + multi-account support via drive/multi_account.go
Gmail Service (gmail/): 3 core tools + multi-account support via gmail/multi_account.go
Account Management (accounts/): 5 tools for managing multiple Google accounts

Basic Implementation

Sheets Service (sheets/): 14 tools (spreadsheet create/get, values get/update/append/clear, sheet duplicate/add/delete/update, dimension insert/delete, cells format/get format) + multi-account support via sheets/multi_account.go
Docs Service (docs/): 3 basic tools (get/create/update documents)

Read the full file on GitHub · 245 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago Changed · +2 tokens per session f66bae10ec79
1mo ago Changed · +5 tokens per session 1dbeb163b0f7
2mo ago First seen · 245 lines · 2,141 tokens per session scan A 3a7e1353a010

Subscribe to this mod's changes

google-mcp-server CLAUDE.md is an instructions file published in the GitHub repository ngs/google-mcp-server (4 stars, last pushed 1mo ago), licensed MIT. It adds 2,148 tokens to every session, about $0.0086 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

ai-tools gmail googlecalendar googledocs googlesheets mcp

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google-mcp-server: Instructions file for Claude Code