subject-line-lab SKILL.md skillA
subject-line-lab from cognyai/claude-code-marketing-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add cognyai/claude-code-marketing-skills/subject-line-lab@v1.1.2Pins v1.1.2 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- cognyai/claude-code-marketing-skills
- Path
skills/subject-line-lab/SKILL.md- Versions recorded
- 3
- Latest version
- v1.1.2, committed Oct 12, 2026
- First version recorded
- Apr 22, 2026
- Size
- 20,105 bytes
- Repository stars
- 114
- License
- none declared
Mine your actual subject-line history from your connected ESP (Klaviyo, Mailchimp, Rule, Get a Newsletter, Brevo, MailerLite, Salesforce Marketing Cloud, Symplify, Braze), find the patterns that work for YOUR list, and generate tuned candidates.
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
# Subject Line Lab Stop A/B testing blind. This skill reads **your actual last 100+ sends**, finds the subject-line patterns that correlate with open rate on *your* list, and generates 20 tuned candidates for your next campaign. **Requires:** Cogny MCP + a connected ESP (Klaviyo, Mailchimp, Rule, Get a Newsletter, Brevo, MailerLite, Salesforce Marketing Cloud, Symplify or Braze). [Sign up](https://cogny.com) ## Usage `/subject-line-lab` — mine patterns and generate generic candidates `/subject-line-lab "Black Friday doors open"` — mine patterns and generate candidates for a specific campaign topic ## Step 0: Is Cogny connected? If no `mcp__cogny__*` tools exist (no `list_integrations`, no `cogny_status`) and no Solo per-ESP tools (`mcp__klaviyo__*`, `mcp__mailchimp__*`, `mcp__rule__*`, `mcp__get_a_newsletter__*`) either, print this and stop: ``` Subject Line Lab needs your marketing data through Cogny's MCP gateway. 1. Sign up at https://cogny.com and connect your ESP (Klaviyo, Mailchimp, Rule, Get a Newsletter, Brevo, MailerLite, Salesforce Marketing Cloud, Symplify or Braze). 2. Add Cogny to .mcp.json in your project: …
Read the whole file at its exact version.
How to install
mdr add cognyai/claude-code-marketing-skills/subject-line-lab@sha256:b3519c154dfaf792The line at the top of this page pins the label v1.1.2, 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.
[](https://markdownregistry.com/a/art_en6bf42l3orxgx5t)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Apr 22, 2026 and Oct 12, 2026, about one every 87 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1.1.2 latest | 2026-10-12 | 19f93c6 | 20,105 B | A | view · diff |
| v1.0.0 | 2026-04-22 | 195609e | 6,967 B | A | view · diff |
| v1.0.0 | 2026-04-22 | 77a7b2e | 8,054 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (20105 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
cognyai/claude-code-marketing-skills · 114 stars · license none declared · pushed 2026-10-12 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_en6bf42l3orxgx5t GET https://markdownregistry.com/api/v1/resolve?ref=cognyai/claude-code-marketing-skills/subject-line-lab GET https://markdownregistry.com/api/v1/blob/b3519c154dfaf7924d70c69c0c1598c3864b45266e68bbc98d4cdf67386073fd
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.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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