What is mcp-server-email CLAUDE.md?

Project instructions for mcp-server-email, a Go service that lets an AI coding agent work with email through IMAP for receiving mail and SMTP for sending it.

Use them when developing or maintaining email features, including multiple accounts, OAuth login, folders, messages, attachments, sending, and connection limits.

They explain the project's structure, dependencies, authentication, account configuration, connection handling, retries, and testing workflow. This helps contributors change the right part of the service safely.

How boutquin/mcp-server-email configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to boutquin/mcp-server-email. 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/boutquin/mcp-server-email/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/boutquin/mcp-server-email

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

[![agentmods](https://agentmods.dev/badge/instructions/boutquin/mcp-server-email/claude-md/github.svg)](https://agentmods.dev/instructions/boutquin/mcp-server-email/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/boutquin/mcp-server-email/claude-md"><img src="https://agentmods.dev/badge/instructions/boutquin/mcp-server-email/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.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/boutquin/mcp-server-email/claude-md"><img src="https://agentmods.dev/badge/instructions/boutquin/mcp-server-email/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,160 This file is loaded in full into every session.

When invoked 1,160 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	$0.01160	$0.01160
Opus 5.5	$0.00464	$0.00464
Sonnet 5.5	$0.00232	$0.00232
Haiku 4.5	$0.00116	$0.00116

Measured 2mo ago against content hash c94707fd9f50, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mcp-server-email 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 2mo 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 · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

mcp-server-email

Go MCP server for email (IMAP/SMTP). 22 tools, multi-account, connection pooling, retry, rate limiting.

Module: github.com/boutquin/mcp-server-email | Go 1.24 | MIT

Package Layout

cmd/mcp-server-email/main.go     → Entry point, slog init, pool init, signal handling, stdio serve
internal/
├── auth/                        → OAuth2 device-code flow, SASL XOAUTH2, token store, provider detection
├── config/                      → ENV/file-based multi-account config loading + provider auto-detection
├── models/                      → Email/Folder/AttachmentInfo structs, message ID codec, error sentinels
├── imap/                        → Client (split: client.go, client_*.go) + Pool + Connector + auth + MIME
├── log/                         → Structured logging (slog) initialization from environment
├── smtp/                        → Client + Pool (lightweight, connect-per-send) + OAuth2 auth retry
├── retry/                       → Token-bucket rate limiter + exponential backoff with jitter
├── tools/                       → All 22 MCP tool handlers + registration
└── resources/                   → email://status resource

Architecture

Data flow: MCP client → stdio → mcp-go router → tool handler → imap.Operations/smtp.Operations interface → pool → client → IMAP/SMTP server.

Key patterns:

Interface-driven DI — imap.Operations (20 methods) and smtp.Operations (3 methods) decouple handlers from protocol clients. Compile-time checks enforce conformance.
Connection pooling with singleflight — IMAP Pool coalesces concurrent requests for the same account via inflight map. Prevents thundering herd.
Force-close with reconnect — connInvalid atomic flag + raw socket close unblocks hung IMAP operations.
Connector adapter — imapclientAdapter collapses go-imap's two-step cmd/wait API into single-call interface for mocking.
Composite message IDs — {account}:{mailbox}:{uid} format. All CRUD tools extract routing info from ID alone.
Retry with exponential backoff + jitter — Shared retry.WithRetry with PermanentError short-circuit.
Token-bucket rate limiting — Per-account, per-protocol (IMAP req/min, SMTP sends/hour).

Read the full file on GitHub · 87 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.

2mo ago First seen · 87 lines · 1,160 tokens per session scan A c94707fd9f50

Subscribe to this mod's changes

mcp-server-email CLAUDE.md is an instructions file published in the GitHub repository boutquin/mcp-server-email (3 stars, last pushed 7mo ago), licensed MIT. It adds 1,160 tokens to every session, about $0.0046 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.

Backend and APIs ai-tools claude email go imap

mcp-server-email CLAUDE.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
mcp-server-email CLAUDE.mdboutquin/mcp-server-email	Instructions file	3	7mo ago	MIT	A	1,160	Claude Code
vibetags com-example-service-NewAnnotationsShowcase-DraftKafkaIntegrationSpike.instructions.mdPIsberg/vibetags	Instructions file	25	yesterday	MIT	A	93	GitHub Copilot
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	yesterday	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot

mcp-server-email: Instructions file for Claude Code