Subject Line Lab
Skill Verified ActiveMine your actual subject-line history from Klaviyo / Mailchimp / Rule / Get a Newsletter, find the patterns that work for YOUR list, and generate tuned candidates
To help marketers improve email open rates by leveraging data-driven insights from their own historical subject line performance.
Features
- Mines historical subject line data from connected ESPs
- Analyzes patterns correlated with open rates
- Generates tuned subject line candidates
- Identifies winning and dragging subject line features
- Provides a pre-send QA recommendation
Use Cases
- When planning a new email campaign and needing subject line ideas
- To optimize subject lines for a specific campaign topic
- To understand what types of subject lines historically perform best on your list
- To reduce manual A/B testing of subject lines by generating data-backed options
Non-Goals
- Generating email body copy
- Connecting to email service providers directly without Cogny MCP
- Performing A/B testing of subject lines
- Analyzing transactional emails or automated flows
Workflow
- Detect connected ESP
- Pull last 100 campaign sends
- Compute baseline metrics
- Extract subject-line features
- Compute lift per feature
- Identify winning and dragging patterns
- Generate tuned subject line candidates
- Save patterns to context
- Create actionable findings (optional)
Practices
- Data analysis
- Email marketing
- Pattern recognition
Prerequisites
- Cogny MCP
- Connected ESP (Klaviyo, Mailchimp, Rule, or Get a Newsletter)
Documentation
- info:Configuration & parameter referenceThe SKILL.md documents the campaign topic argument and lists prerequisites but does not explicitly detail default values or precedence orders for configuration.
Execution
- info:ValidationThe `argument-hint` suggests a string input for campaign topic, but formal schema validation is not explicitly detailed in the SKILL.md.
Compliance
- info:GDPRThe skill processes email history which may contain personal data; it does not explicitly sanitize this data before LLM processing.
Installation
npx skills add cognyai/claude-code-marketing-skillsRuns the Vercel skills CLI (skills.sh) via npx — needs Node.js locally and at least one installed skills-compatible agent (Claude Code, Cursor, Codex, …). Assumes the repo follows the agentskills.io format.
Quality Score
VerifiedTrust Signals
Similar Extensions
Acquisition Channel Advisor
100Evaluate acquisition channels using unit economics, customer quality, and scalability. Use when deciding whether to scale, test, or kill a growth channel.
Social Media Analyzer
100Social media campaign analysis and performance tracking. Calculates engagement rates, ROI, and benchmarks across platforms. Use for analyzing social media performance, calculating engagement rate, measuring campaign ROI, comparing platform metrics, or benchmarking against industry standards.
Revenue Audit
85Audit an email marketing program for revenue leaks — missing flows, dormant high-value subscribers, under-segmentation, promo gaps, stale automations — ranked by estimated $ impact
OraClaw Forecast
100Time series forecasting for AI agents. ARIMA and Holt-Winters predictions with confidence intervals. Predict revenue, traffic, prices, or any sequential data. Sub-5ms inference.
Measure Dashboard Requirements
100Specifies requirements for an analytics dashboard including metrics, visualizations, filters, and data sources. Use when requesting dashboards from data teams, defining KPI tracking, or documenting reporting needs.
Meta Observer
100Track skill performance and emerging patterns