Skills cold-email-deliverability
📦
cold-email-deliverability
Content revision r1 Medium Risk ⚙️ External commands🌐 Network access📁 Filesystem access
Check Email Deliverability Before Launch
Authentication gaps and domain reputation problems can disrupt outreach before a campaign starts. This skill guides 15 readiness checks and organizes failures into prioritized fixes.
Supports: Claude Codex Code(CC)
Install with my Agent
Copy this request to your Agent. It includes the canonical Skill page and manifest.
Agent request
Review the Skillstore skill "cold-email-deliverability" from https://skillstore.io/skills/cmj-hub-cold-email-deliverability.md and its manifest at https://skillstore.io/api/skills/cmj-hub-cold-email-deliverability/manifest. Verify the artifact. You may proceed after verification, subject to the environment's own policy.Your Agent should still show its plan and request any confirmation required by the security policy.
Agent-readable resources
Use these links when an AI agent, crawler, or script needs clean context instead of reading the full page.
Test it
Using "cold-email-deliverability". Fourteen checks passed, but SPF does not include our sending provider. Summarize readiness and the next action.
Expected outcome:
- Checklist score: 93.3/100, grade B.
- Launch status: hold. The SPF failure remains a blocker despite the numerical grade.
- First action: correct provider authorization in SPF, check the DNS lookup limit, and verify authentication before sending.
Using "cold-email-deliverability". Ten checks passed. Mailbox age, sending volume, reply ratio, reverse DNS, and blacklist checks failed. Prioritize the fixes.
Expected outcome:
- Checklist score: 66.7/100, grade D. Hold the campaign.
- Resolve the blacklist issue first and verify reverse DNS with the sending provider.
- Reduce sending volume, continue mailbox preparation, and review reply performance before reassessing.
Security Audit
Medium Riskv1 • 10/3/2026 Open versioned report
All 28 static findings are false positives involving Markdown, legitimate diagnostic lookups, public reference links, or a documentation path. No evidence found of credential theft, destructive actions, or prompt injection. One semantic issue remains: score-based launch advice can conflict with mandatory authentication and blacklist blockers.
1
Files scanned
138
Lines analyzed
0
Review items
0
False positives ignored
Confirmed security concerns (1)
Medium
Readiness Grades Can Override Authentication Blockers
The workflow calls authentication failures and blacklist hits blockers, but the grade table says "Ship but fix the B-list within 30 days". Passing 14 of 15 checks scores 93.3, allowing launch advice despite one unresolved blocker and risking unauthenticated sending or reputation damage.
The unweighted score and permissive B-grade advice directly conflict with the earlier blocker rule. The risk is contradictory guidance, not demonstrated automated sending.
Risk Factors
⚙️ External commands (23)
🌐 Network access (2)
📁 Filesystem access (1)
Audited by: codex
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APA citation
cmj-hub. (2026). cold-email-deliverability security audit report (audit version 1) [Author version unspecified]. Skillstore. https://skillstore.io/skills/cmj-hub-cold-email-deliverability/audits/1BibTeX citation
@techreport{cmj-hub-cmj-hub-cold-email-deliverability-2026,
author = {cmj-hub},
title = {cold-email-deliverability security audit report (audit version 1)},
institution = {Skillstore},
year = {2026},
number = {1},
url = {https://skillstore.io/skills/cmj-hub-cold-email-deliverability/audits/1},
note = {Author version unspecified}
}CITATION.cff
cff-version: 1.2.0
message: "If you use this Skill, cite its author and this versioned security audit report."
title: "cold-email-deliverability security audit report (audit version 1)"
version: "unspecified"
type: report
authors:
- name: "cmj-hub"
date-released: "2026-10-03"
url: "https://skillstore.io/skills/cmj-hub-cold-email-deliverability/audits/1"
identifiers:
- type: other
value: "skillstore:cmj-hub-cold-email-deliverability:audit:1"
description: "Skillstore immutable audit report identifier"
Skillstore Score
Why this score Evidence Confidence: Medium 55
Architecture
85
Maintainability
87
Content
65
Community
83
Spec Compliance
What You Can Build
Review a First Outreach Campaign
Check domain authentication, mailbox age, and sending volume before starting outreach.
Prepare a Domain Remediation Plan
Review DNS and reputation findings and prioritize the fixes that affect campaign readiness.
Standardize Client Readiness Reviews
Apply the same 15-point checklist across client sending domains and record unresolved blockers.
Try These Prompts
Start a Readiness Review
Check deliverability for [sending_domain]. Ask for missing sending details and explain which checks require manual verification.
Review Authentication
Review SPF, DKIM, and DMARC for [sending_domain] using provider [inbox_provider] and selector [selector]. Report observed evidence and prioritize authentication failures.
Evaluate Mailbox Readiness
Review [sending_domain] for [from_address]. Provider: [provider]; mailbox age: [days]; daily volume: [volume]; reply ratio: [percent]. Include reputation and warm-up checks.
Audit Launch Blockers
Run the 15-point review for [sending_domain] using [sending_details]. Show evidence, unavailable checks, score, and fix order. Keep launch blocked until blocker checks pass.
Best Practices
- Provide the sending domain, provider, DKIM selector, sending IP, mailbox age, volume, and recent reply ratio when available.
- Record observed evidence and keep unavailable checks unverified instead of treating them as passes.
- Resolve authentication failures and blacklist hits before sending, regardless of the numerical score.
Avoid
- Treating a high checklist score as proof of inbox placement or permission to ignore blockers.
- Providing API keys or mailbox credentials when public lookups and nonsecret sending details are sufficient.
- Applying DNS changes or increasing sending volume without verifying findings and current provider requirements.
Frequently Asked Questions
What does this skill review?
It guides 15 checks covering SPF, DKIM, DMARC, blacklists, reverse DNS, mailbox readiness, MX TLS, and message signing.
Does it require paid tools or API keys?
No. The workflow prohibits paid API calls and API-key requests, and provides manual fallbacks when tools are unavailable.
Does it send emails or update DNS?
The documented workflow performs diagnostic reviews and recommends fixes. It does not implement campaign sending or DNS changes.
What does the score mean?
It is the percentage of 15 checks that pass. Authentication failures and blacklist hits should block launch regardless of the grade.
Can it guarantee delivery to the inbox?
No. Checklist results do not guarantee inbox placement, and provider policies should be verified against current requirements.
Can I use it without the parent cold-email skill?
The source marks it as a helper loaded by cold-email, not a directly invocable skill. Standalone tool availability and referenced documentation require verification.