Guidance for diagnosing, protecting, and improving B2B email deliverability across cold outbound, opted-in marketing, and newsletter programs — trigger when a user asks about inbox placement, sender reputation, spam filters, email infrastructure, or engagement metrics.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Email Deliverability
## Overview
This skill covers B2B email deliverability best practices spanning cold outbound infrastructure, opted-in marketing programs, technical configuration, engagement signals, and metric interpretation. All practices are sourced exclusively from Exit Five podcast guests across 6 episodes. Do not supplement with general knowledge not represented here — gaps in coverage are intentional.
---
## Infrastructure: Domains, IPs, and Inboxes
**Protect your primary domain at all costs.**
- Never send cold outbound email from your primary company domain (e.g., `yourcompany.com`). Use secondary domains (e.g., `try.exitfive.com`, `get.exitfive.com`) instead. If the primary domain is blacklisted, it damages your entire business's email deliverability. (Source: Alex Fine, Episode #256)
- Use secondary domains rather than subdomains for email campaigns. Subdomains are tied to your primary domain's reputation; secondary domains are fully isolated. (Source: Alex Fine, Episode #256)
…
The line at the top of this page pins the label v2026-04-20, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_dsjya6r2qyfzuzbe
GET https://markdownregistry.com/api/v1/resolve?ref=the-nam-shub/e5-real-skills/email-deliverability
GET https://markdownregistry.com/api/v1/blob/57f12772600819ebee839873d021559a320352e6d7808046e672e112aba581f8
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
the-nam-shub/e5-real-skills · skills/abm-field-events/SKILL.md · Guidance for planning and executing ABM field events—including dinners, lunches, activations, and suite sponsorships—to…
the-nam-shub/e5-real-skills · skills/account-based-marketing/SKILL.md · Guidance for planning, executing, and measuring account-based marketing (ABM) programs in B2B; trigger when a user asks…
the-nam-shub/e5-real-skills · skills/agency-and-vendor-management/SKILL.md · Guidance for selecting, structuring, and managing relationships with marketing agencies, freelancers, and external…
the-nam-shub/e5-real-skills · skills/ai-adoption-and-team-enablement/SKILL.md · Guidance for marketing leaders on adopting AI tools, enabling teams, structuring workflows, and navigating the…
the-nam-shub/e5-real-skills · skills/ai-content-creation-and-repurposing/SKILL.md · Guidance for using AI tools to create, repurpose, and distribute B2B marketing content—covering workflows, quality…
the-nam-shub/e5-real-skills · skills/ai-governance-and-responsible-use/SKILL.md · Guides marketers on how to adopt AI tools responsibly, govern their use, and build organizational capability — trigger…
the-nam-shub/e5-real-skills · skills/ai-sales-intelligence-and-outreach/SKILL.md · Guidance for using AI to extract intelligence from sales calls, personalize outbound outreach, build sales enablement…
the-nam-shub/e5-real-skills · skills/ai-workflow-automation-and-agent-building/SKILL.md · Guides marketers through building, structuring, and managing AI workflows and agents for marketing automation — trigger…
the-nam-shub/e5-real-skills · skills/analyst-relations/SKILL.md · Guidance on building and leveraging analyst relationships (Gartner, Forrester, IDC) to drive credibility, category…
rampstackco/claude-skills · skills/email-deliverability/SKILL.md · Make sure email actually reaches inboxes. Use this skill when setting up email authentication (SPF, DKIM, DMARC)…
ericrisco/rsc-harness · skills/email-deliverability/SKILL.md · Use when mail already sent lands in spam, is rejected, or fails the Gmail/Yahoo bulk-sender checks and the fix is…
the-utopia-studio/skills · plugins/utopia-gtm/skills/email-deliverability/SKILL.md · Use this skill when emails hit spam, open rates drop, a domain or IP gets blocklisted, or a sender wants a…
