ab-copy-writer

name	ab-copy-writer
description	Generate A/B copy variants for any piece of marketing copy with a hypothesis per variant. Use when the user says "A/B test this", "write variants", "give me options", "test different angles", "copy variants", "ab copy", "test this headline", "multiple versions", or wants to test copy before publishing. Produces 3-5 variants per copy element with angle, hypothesis, and expected audience response. Reads brand voice and ICP from knowledge/.
reads	["knowledge/brand/voice.md","knowledge/icp/personas.md","knowledge/markets/positioning.md","knowledge/learnings.md"]
writes	["output/ab-copy/"]

ab-copy-writer

Produces testable copy variants. Every variant has a distinct angle, a hypothesis for why it will outperform, and a predicted audience response. Stops marketers from shipping one version and guessing.

When to use

• "Write 3 variants of this LinkedIn post"
• "Give me A/B options for this email subject line"
• "Test different angles for our landing page hero"
• "I need to A/B test this ad headline"
• "Write copy variants for our webinar title"
• "Give me 5 versions of this CTA"

Inputs needed

1. The copy element: what needs variants (headline, subject line, hero, CTA, LinkedIn hook, ad copy, webinar title, email opener)
2. The source: existing copy to riff on, or a brief description of what it should accomplish
3. Number of variants: default is 3, max is 5
4. Channel: where this copy will run (LinkedIn, email, landing page, ad, webinar registration page)
5. What's being tested: angle, tone, format, CTA, or length (ask if not clear)

Angles this skill tests

For each variant, pick a distinct angle from this list. Never use the same angle twice in one set:

Angle	Description	When it wins
Outcome-led	Leads with the specific result	When audience is ROI-focused and numbers-driven
Pain-led	Opens on the problem, not the solution	When audience is in active pain and aware of it
Speed-led	Emphasizes time-to-value	When audience is impatient or under pressure
Contrarian	Challenges a common belief	When audience is saturated with standard messaging
Social proof	Leads with a customer result or name	When audience trusts peers more than vendors
Curiosity gap	Creates a knowledge gap that demands closing	When audience is information-hungry
Specificity	Extremely specific number or detail as the hook	When vague claims are common and specifics stand out
Fear of missing out	What happens if you don't act	When cost of inaction is high and under-communicated
How-to	Practical, instructional framing	When audience wants actionable takeaways
Founder/operator voice	Written as a practitioner to a practitioner	When audience distrusts brand voice

Process

1. Load context. Read knowledge/brand/voice.md (for tone and style rules) and knowledge/icp/personas.md (for what this audience responds to). If either is missing, ask the user for the relevant context directly.

2. Check knowledge/learnings.md for any past A/B test results or copy performance data. If a previous test showed "outcome-led beats pain-led for our ICP", factor that in and note it.

3. Understand the goal. Ask if not provided: "What action should this copy drive? And what's the one thing the audience should feel or believe after reading it?"

4. Generate variants. For each:

   ## Variant [A/B/C/D/E]: [Angle name]
   
   **Copy:**
   [the actual copy - complete and ready to use]
   
   **Angle**: [name from the angles table]
   **Hypothesis**: [1-2 sentences on why this angle should outperform the others for this specific audience]
   **Predicted response**: [how the ICP is likely to feel reading this]
   **Best for**: [which segment of the ICP or which stage of the funnel this variant suits most]
   **Watch for**: [what signal would tell you this variant is winning - clicks, replies, saves, conversions]
   

5. Recommend the test setup:

   ## Recommended test setup
   
   **Test**: [Variant A] vs [Variant B] (start with the two most different angles)
   **Why these two**: [1 sentence on why this pairing gives the clearest signal]
   **Sample size needed**: [rough guidance - "at least 500 impressions per variant before reading results"]
   **How long to run**: [1-2 weeks for LinkedIn organic, 7 days minimum for paid, 3+ sends for email]
   **Primary metric**: [clicks / replies / saves / open rate / conversion - pick one]
   **How to read results**: [what delta counts as a win: ">10% difference in CTR is signal, <5% is noise"]
   

6. Self-check each variant:

   • Distinct angle from every other variant - no two variants are the same approach with different words
   • Matches knowledge/brand/voice.md style rules (no em dashes, no banned phrases, correct POV)
   • Uses language from knowledge/icp/personas.md where relevant
   • Hypothesis is specific to the ICP, not generic ("this will outperform because our ICP is measured on activation rate, not awareness, so outcome-led copy speaks directly to their KPI")

7. Save to output/ab-copy/<DD-MM-YYYY>-<copy-element-slug>.md with frontmatter:

   ---
   format: ab-copy
   element: [headline|subject-line|hero|cta|hook|ad]
   channel: [linkedin|email|landing-page|ad|webinar]
   variants: [number]
   angles: [list of angles used]
   created: DD-MM-YYYY
   ---
   

8. Offer follow-ups:

   • "Run /retro after the test and log which variant won and why. This gets appended to knowledge/learnings.md so future copy benefits from the result."
   • "Run /content-writer or /linkedin-post to build out the winning variant into a full piece."
   • "Want me to write the full ad set or email sequence using Variant [X] as the control?"

Copy length by channel

Channel	Element	Length
LinkedIn	Hook (first 2 lines)	15-25 words
LinkedIn	Full post	80-220 words
Email	Subject line	6-10 words
Email	Preview text	8-12 words
Email	Opener (first sentence)	10-20 words
Landing page	H1	5-10 words
Landing page	Sub-headline	15-25 words
Google ad	Headline	30 chars max
Google ad	Description	90 chars max
LinkedIn ad	Intro text	150 chars max
Webinar	Title	8-12 words
CTA button	Text	2-5 words

Rules

• Never produce variants that are only cosmetically different (swapping one word is not a different angle).
• Never use an angle that knowledge/learnings.md has already shown underperforms for this ICP without flagging: "Past data shows [angle] underperformed. Including it here for completeness, but Variant X is the higher-confidence bet."
• Every hypothesis must reference the ICP specifically. "This will perform well" is not a hypothesis. "Our ICP (Head of Growth, measured on activation rate) will respond to specificity because they are data-fluent and distrust vague ROI claims" is.
• Always recommend starting the test with the two most different variants, not adjacent ones. Adjacent variants give weak signal.
• If the user provides existing copy, always include one variant that is a direct evolution of their version (keep their angle, sharpen the execution) alongside genuinely different angles. They may want a baseline.