ab-test-designer

ab-test-designer is a skill for Claude Code from saski/arnesto. It costs 28 tokens per session (498 once invoked), scanned A, a copy of ab-test-designer, Unlicense.

A guide for designing A/B tests, which compare a current experience with a changed version to see which performs better.

In plain words
What is it for?
Use it when testing a feature or design change, checking a hypothesis before a wider rollout, improving conversion rates, or choosing between alternatives.
Why use it?
It helps turn a product idea into a measurable experiment instead of relying on opinion. The plan defines the hypothesis, metrics, audience, sample size, duration, and analysis method.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: installed under .agents/ (shared by several agents).

Good fit Use it when testing a feature or design change, checking a hypothesis before a wider rollout, improving conversion rates, or choosing between alternatives.

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Install with agentmods
npx agentmods add skills/saski/arnesto/ab-test-designer
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add saski/arnesto --skill ab-test-designer
Clone the repo
git clone --depth 1 https://github.com/saski/arnesto

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ab-test-designer

README.md
[![agentmods](https://agentmods.dev/badge/skills/saski/arnesto/ab-test-designer.svg)](https://agentmods.dev/skills/saski/arnesto/ab-test-designer)
Your own site
<a href="https://agentmods.dev/skills/saski/arnesto/ab-test-designer"><img src="https://agentmods.dev/badge/skills/saski/arnesto/ab-test-designer.svg" alt="Measured on agentmods" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 498 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00028 $0.00498
Opus 5 $0.00014 $0.00249
Sonnet 5 $0.00006 $0.00100
Haiku 4.5 $0.00003 $0.00050

Measured 7d ago against content hash bb5d8e7727b5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

ab-test-designer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to ab-test-designer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/ab-test-designer/SKILL.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Domain Context

This skill implements a proven product management framework. The approach combines best practices from industry leaders and is designed for practical application in day-to-day PM work.

Input Requirements

  • Context about your product, feature, or problem
  • Relevant data, research, or constraints (recommended but optional)
  • Clear articulation of what you're trying to achieve

A/B Test Designer

When to Use

  • Testing a new feature or design variation
  • Validating a hypothesis before full rollout
  • Optimizing conversion rates or key metrics
  • Choosing between multiple design approaches
  • Need to make a data-driven decision on a change

What This Skill Does

Helps you design rigorous A/B tests with clear hypotheses, success metrics, sample size calculations, and analysis plans.

Instructions

Help me design an A/B test for [feature/change]. Include:

  1. Hypothesis

    • Current situation and metrics
    • Proposed change
    • Expected impact and why
  2. Test Design

    • Primary success metric
    • Secondary metrics
    • Sample size needed
    • Test duration
    • User segments to include/exclude
  3. Variants

    • Control (A): current experience
    • Variant (B): new experience
    • Any additional variants (C, D, etc.)
  4. Risks and Controls

    • Potential negative impacts
    • Guardrail metrics
    • When to stop the test early
  5. Analysis Plan

    • Statistical significance threshold
    • How to handle edge cases
    • Decision criteria

Feature context: [Add context about the change you want to test]

Best Practices

  • Start with a clear, falsifiable hypothesis
  • Choose one primary metric to avoid multiple comparison issues
  • Calculate sample size upfront based on expected effect size
  • Run tests for full weekly cycles to account for day-of-week effects
  • Set a minimum test duration (usually 1-2 weeks)
  • Define success criteria before running the test
  • Monitor guardrail metrics (revenue, errors, performance)

Example

Input: Testing new onboarding flow vs current 3-step process Output: Hypothesis (new 1-step flow will increase co...

Read the full file on GitHub · 75 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 75 lines · 28 tokens per session scan A bb5d8e7727b5

Subscribe to this mod's changes

ab-test-designer is a skill published in the GitHub repository saski/arnesto (5 stars, last pushed today), licensed Unlicense. It adds 28 tokens to every session and 498 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to ab-test-designer, differing in 0 lines, and is treated as a copy.