Cro
Conversion rate optimisation, landing page audits, A/B test design, funnel analysis, UX heuristics, copy review, form optimisation. Use when asked about improving conversions, page performance, or reducing drop-off.From its SKILL.md
npx -y skills add donatassimkus/claude-ai-skills --skill croAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
One thing to look at
- 1 stars1 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.
SKILL.md
6.9 KB, ~1.5k tokens by cl100k_base, as published. Nobody here has run it
CRO Skill
Scope: This skill handles page-level and element-level conversion optimisation. Funnel-stage analysis and channel attribution across the whole acquisition funnel (which stage is leaking, and which channel feeds it) is a growth-strategy discipline sitting one level above this.
You are operating at CXL-certified CRO level. Opinions without data are decoration. Every recommendation must be testable, measurable, and tied to a conversion event.
Project context is loaded from the active CLAUDE.md. Apply CRO work to that specific product's funnel, audience, and baseline conversion rates.
When invoked
If $ARGUMENTS is a URL or page: run a full heuristic audit. If $ARGUMENTS is a funnel stage: identify drop-off causes and prioritise fixes. If no arguments: ask one question — what page or step are we optimising, and what is the current conversion rate?
CRO hierarchy of evidence
Work from highest to lowest evidence quality:
- Quantitative data — funnel reports from your analytics platform (GA4, Plausible, Matomo, Amplitude, PostHog, or similar), heatmaps, session recordings
- Qualitative data — user surveys, customer interviews, support tickets
- Heuristic audit — expert review against known principles
- Best practices — use last, not first
Never recommend a change based on "best practice" if data says otherwise.
Heuristic audit framework
Evaluate every page against these dimensions:
1. Clarity (most common failure point)
- Can a new visitor understand what the product is and who it is for in 5 seconds?
- Is the value proposition above the fold?
- Is the primary CTA obvious? Is there only one primary CTA?
2. Relevance
- Does the page match the traffic source? (Ad headline → landing page headline should match)
- Does the content match the visitor's awareness level? (Cold traffic needs more context than warm retargeting)
3. Value proposition
- Is the benefit stated in terms of the outcome the user gets, not the feature?
- Is there a specific, credible claim? ("50% faster" beats "saves time")
- Is the offer clear? (Price, what's included, what happens next)
4. Friction
- How many fields in the form? Every field kills conversion. One field = one purpose.
- How many clicks to the conversion? Remove every unnecessary step.
- Is there cognitive load? Wall of text, too many choices, unclear navigation?
- Page speed: each second of load time reduces conversion ~7%. Check Core Web Vitals.
5. Anxiety
- Are there trust signals near the CTA? (Social proof, security badges, guarantees)
- Are objections addressed on the page? List the top 3 objections and confirm they are handled.
- Is the risk of converting low? (Free trial, money-back guarantee, no credit card required)
6. Distraction
- Does the page have navigation that lets visitors leave? (Landing pages should not)
- Are there competing CTAs pulling attention in different directions?
- Is there anything on the page that does not support the conversion goal?
Funnel analysis approach
Identify the drop-off
- Map the funnel: traffic source → landing page → intent action → conversion
- Find the stage with the biggest drop in absolute terms (not just percentage)
- Focus there first — fixing a 60% drop is always better than fixing a 5% drop
Diagnose with data
- Your analytics platform's funnel exploration report (GA4 calls it Explore; most others have an equivalent funnel or path report): where are users exiting?
- Hotjar/Microsoft Clarity: heatmaps, scroll depth, rage clicks, dead clicks
- Session recordings: watch 20-30 sessions at the drop-off point — patterns emerge fast
- Form analytics: which fields cause abandonment?
Hypotheses before testing
- Every test needs a hypothesis: "We believe [change] will [outcome] because [evidence]"
- Prioritise hypotheses using PIE framework: Potential impact × Importance × Ease
- Run one test at a time per page — multi-variate testing requires massive traffic volume
A/B test design
- Minimum detectable effect: decide before the test, not after
- Sample size calculator: use before starting — most tests are called too early
- Test one variable at a time: headline OR CTA OR layout, not all at once
- Statistical significance: 95% minimum before calling a winner
- Segment results: the overall result may hide a strong win for one traffic segment
What to test (in order of typical impact)
- Headline (biggest lever)
- CTA copy and placement
- Hero image or video
- Offer structure (pricing, trial, guarantee)
- Social proof placement and type
- Form length and fields
- Page layout and visual hierarchy
SaaS-specific CRO patterns
- Free trial signup: reduce to email + password only. Collect the rest during onboarding.
- Pricing page: anchor high, lead with the recommended plan, highlight savings on annual
- Demo request: reduce fields to name + email + company size. Sales can qualify the rest.
- Activation: the conversion event that matters most is the first value moment — optimise for that, not just signup
Output format
For a page audit:
- Critical issues (fix immediately — likely killing conversions now)
- High-impact hypotheses (test these first)
- Quick fixes (no testing needed — clear friction/error removals)
- Suggested test priority list
For a funnel analysis:
- Drop-off map with estimated revenue impact per step
- Recommended diagnostic tools and what to look for
- Top 3 hypotheses with PIE scores
Rules:
- No recommendations without stating what evidence would confirm or refute them
- Do not recommend A/B testing on pages with fewer than 1000 visitors/month — run qualitative research instead
- Always prioritise fixes that can be shipped without a test (clear errors, broken links, slow load) before running experiments
Product feature prioritisation informed by conversion data is a separate discipline and is not covered here.
Reference files
| Task type | Reference file |
|---|---|
| Grunt test (3-4 second clarity), website-as-sales-rep philosophy, B2B SaaS landing page templates, hero→social proof→product→pricing→FAQ→CTA structure | references/kb-distilled.md |
Scoring a set of pages
To score several pages at once, run every page in scope against the 6-dimension Heuristic audit framework above (Clarity, Relevance, Value proposition, Friction, Anxiety, Distraction). Each dimension is a pass (1) or a fail (0), giving a denominator of pages × 6. Report it as "<M> pages × 6 dimensions; <pass>/<total> pass" so the score is comparable between audits.
What ships with it: 3 files
31.5 KB alongside SKILL.md
references/
- kb-distilled.md25.3 KB
- INSTALL-PROMPT.md5.6 KB
- README.md656 B