Email Marketing Bible
Email marketing skill for Claude Code. 88K words, 908 sources, 19 industry playbooks. Install the skill and Claude becomes your email marketing expert.
Install: /plugin marketplace add CosmoBlk/email-marketing-bible
Works with Claude Code · 342 GitHub stars
Install
/plugin marketplace add CosmoBlk/email-marketing-bibleInstall command taken from the project's README or registry entry. Always review code before running it.
README excerpt
Read full README on GitHub →Email Marketing Bible
By George Hartley, co-founder of Nitrosend.
The AI email automation skill for Claude, ChatGPT, and any agent.
Version 2.8.2, 13 October 2026.
It audits your setup, builds flows from a prompt, drafts copy in your voice, directs email design instead of accepting the model's defaults, tells you why you are in spam, and runs your ESP through MCP with a hard rule that nothing blasts without your say-so.
Built from research across 900+ sources, the experience of running SmartrMail (~12,000 customers, 6 billion emails, acquired 2022), and field notes from running an ESP through agents. 19 chapters, playbooks for 19 verticals, 47 curated email designs. Free and open source.
Install
Install one, not both. In Claude Code use the plugin; a clone into ~/.claude/skills also carries the plugin manifest and can load the skill twice.
Claude Code (plugin, needs a recent Claude Code). In Claude Code, run:
/plugin marketplace add CosmoBlk/email-marketing-bible
/plugin install email-marketing-bible@email-marketing-bible
Other agents (Codex, Cursor and others that read skills):
npx skills add CosmoBlk/email-marketing-bible
Or git clone the repo into that agent's skills folder.
ChatGPT, Gemini or any single-file tool: give it the raw core file, https://raw.githubusercontent.com/CosmoBlk/email-marketing-bible/main/SKILL.md. The core works on its own: when references/ isn't there, it reads https://emailmarketingskill.com/llms.txt and fetches the matching reference file or chapter by the full URL listed there. Claude's web fetch only opens a URL that appears in a user message or an earlier search or fetch result, so if your agent says the site is blocked, paste https://emailmarketingskill.com/llms.txt into the chat and ask again.
Why this exists
In 2026 the job changed. Agents build the campaign, segment the audience, draft the copy and stage the send; the marketer directs. That only works if the agent runs on real benchmarks and hard guardrails. This skill is that discipline layer: the patterns that repeat across industries, the mistakes that destroy deliverability, the anti-slop rules for copy and design, and the send-safety gates that keep one prompt from mailing the wrong thing to your whole list.
What the skill does
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