---
title: "Email playbook · Agent Wranglers"
url: https://agentwranglers.se/playbook/email
updated: 2026-10-20
licence: "All rights reserved"
---

# Email playbook

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

An email playbook for any app or business that sends email, from password resets to newsletters. It covers the message itself, the sending domain, delivery, unsubscribing, layout, privacy, security and automation.

Every rule rests on the standards that mailbox providers enforce, such as the RFCs and the sender rules of Gmail, Yahoo and Microsoft. Each one has a check you can run, often a DNS lookup, a header to read or a test send.

Start with [Sending domain and authentication](https://agentwranglers.se/playbook/email/sending-domain-and-authentication). Without SPF, DKIM and DMARC, large providers reject bulk mail outright.

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email`.

## Chapters

1. [Message basics](https://agentwranglers.se/playbook/email/message-basics): Build every message to the internet standards, with the right headers, a plain-text part, UTF-8, a declared language and a size inboxes accept. (5 required, 3 recommended)
2. [Sending domain and authentication](https://agentwranglers.se/playbook/email/sending-domain-and-authentication): Prove each message is yours with SPF, DKIM and DMARC on aligned domains, and send it over checked TLS, or large inboxes reject it. (6 required, 3 optional)
3. [Deliverability](https://agentwranglers.se/playbook/email/deliverability): Reach the inbox by meeting the big providers' sender rules, keeping complaints low, separating mail streams and sending only to people who asked. (4 required, 4 recommended)
4. [Unsubscribe and bounces](https://agentwranglers.se/playbook/email/unsubscribe-and-bounces): Let people leave with one click and honour it within two days. Treat bounces and complaints as orders to stop, and retry only temporary errors. (8 required, 1 recommended, 1 optional)
5. [Layout and accessibility](https://agentwranglers.se/playbook/email/layout-and-accessibility): Build email that every client can show and every reader can use. Semantic HTML, live text, clear contrast, small files and a test send to each major client. (8 required, 4 recommended)
6. [Email privacy](https://agentwranglers.se/playbook/email/email-privacy): Send only what the message needs and track as little as you can. Opens are not reliable, so ask first, keep proof of consent and keep logs lean. (5 required, 1 recommended)
7. [Email security](https://agentwranglers.se/playbook/email/email-security): Keep attackers away from your recipients and readers. Send safe links, single-use sign-in links and no secrets, scripts or risky files, and resist phishing. (5 required, 1 recommended, 1 optional, 1 avoid)
8. [Automation and agents](https://agentwranglers.se/playbook/email/automation-and-agents): Make email that machines can use. Correct calendar invites, structured order data, honest automated mail and messages AI assistants can read safely. (3 required, 2 recommended, 1 optional)

See all 67 rules on one page in the [checklist](https://agentwranglers.se/playbook/email/checklist).