Borrowing it
Nothing to install: this file belongs to cunicopia-dev/gmail-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/cunicopia-dev/gmail-mcp/master/CLAUDE.mdgit clone --depth 1 https://github.com/cunicopia-dev/gmail-mcpWrote 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.
[](https://agentmods.dev/instructions/cunicopia-dev/gmail-mcp/claude-md)<a href="https://agentmods.dev/instructions/cunicopia-dev/gmail-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/cunicopia-dev/gmail-mcp/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>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.
<a href="https://agentmods.dev/instructions/cunicopia-dev/gmail-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/cunicopia-dev/gmail-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.03556 | $0.03556 |
| Opus 5.5 | $0.01422 | $0.01422 |
| Sonnet 5.5 | $0.00711 | $0.00711 |
| Haiku 4.5 | $0.00356 | $0.00356 |
Grade A, and why
gmail-mcp 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.
How it starts
The opening of the file, as written. The whole thing — 243 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Gmail MCP — Development Guide
What it is
A local stdio MCP server giving an AI agent unified access to multiple
Gmail accounts at once. The native Anthropic Gmail connector binds one
account per OAuth grant; this server holds refresh tokens for N accounts in
a local SQLite store and routes each tool call to the right inbox via an
account argument. search_all_accounts fans one query across every inbox.
Layout
src/gmail_mcp/
server.py — MCP server entry point, tool registration, dispatch, per-account routing
auth.py — gmail-mcp-auth CLI: browser OAuth bootstrap (NOT an MCP tool)
store.py — SQLite token store (accounts table keyed by email)
gmail.py — per-account service build + token refresh; pure MIME parsing/formatting
config.py — path resolution (DB, client secret) + SCOPES constant
tests/ — pytest; Gmail client is mocked, no live network
Module responsibilities
| Module | Purpose |
|---|---|
server.py |
Registers MCP tools, dispatches calls, resolves account → service. All Gmail network I/O runs in asyncio.to_thread (the google client is sync). |
auth.py |
add / list / remove subcommands. add runs InstalledAppFlow.run_local_server, reads the granted email from users.getProfile, upserts into the store. |
store.py |
TokenStore CRUD over sqlite3. upsert preserves added_at; touch stamps last_used_at; update_token persists refreshed access tokens. |
gmail.py |
build_service(account, store) builds google-auth Credentials, refreshes if stale, persists the new token, returns a Gmail client. Plus pure helpers — parse_message, extract_body_and_attachments, strip_html, resolve_label_ids, build_mime_message, sanitize_filename, screen_attachment, decode_b64url_bytes, formatters. |
config.py |
db_path(), client_secret_path(), attachments_dir(), max_attachment_bytes(), SCOPES. |
OAuth model
- Auth is a CLI, not a tool — the OAuth flow needs a browser, which an
MCP tool can't drive.
gmail-mcp-auth addruns the installed-app loopback flow and stores the refresh token. - Client config comes from a downloaded Google "Desktop app" OAuth client
JSON at
~/.gmail-mcp/client_secret.json(envGMAIL_MCP_CLIENT_SECRET). Never hardcodeclient_id/client_secret. - Token store: SQLite at
~/.gmail-mcp/tokens.db(envGMAIL_MCP_DB). Keyed by email. Holds refresh_token + last access-token blob + scopes. - Refresh: google-auth's
Requesttransport refreshes the access token on demand;build_servicepersists the refreshed blob back to the DB. - Scopes (one constant,
config.SCOPES):gmail.readonly,gmail.compose,gmail.modify,gmail.settings.basic. Granular — NOT fullmail.google.com, and nogmail.send/ nogmail.settings.sharing(see Security model). WideningSCOPESdoes NOT retro-grant existing accounts — each must re-rungmail-mcp-auth addto re-consent, or the new tool returns403 insufficient scope.
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 First seen · 243 lines · 3,556 tokens per session scan A 5c84a25307a3
gmail-mcp CLAUDE.md is an instructions file published in the GitHub repository cunicopia-dev/gmail-mcp (5 stars, last pushed 2mo ago), licensed MIT. It adds 3,556 tokens to every session, about $0.0142 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.
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