ab-test-setup

ab-test-setup is a skill for Claude Code from frank-luongt/faos-skills-marketplace. It costs 0 tokens per session (1,065 once invoked), scanned A, a copy of ab-test-setup, Apache-2.0.

A structured guide for planning an A/B test, which compares two versions of something with real users. It checks the user problem, hypothesis, audience, success metric, traffic, and minimum detectable effect before implementation.

In plain words
What is it for?
Use it to define a test hypothesis, choose measurements, estimate sample needs, and confirm that an experiment is ready to run.
Why use it?
It prevents invalid experiments, changing the plan mid-test, or drawing conclusions from insufficient data.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the faos-analyst plugin — 22 skills, 6 commands shipped together

Good fit Use it to define a test hypothesis, choose measurements, estimate sample needs, and confirm that an experiment is ready to run.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/frank-luongt/faos-skills-marketplace/ab-test-setup
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 frank-luongt/faos-skills-marketplace --skill ab-test-setup
Clone the repo
git clone --depth 1 https://github.com/frank-luongt/faos-skills-marketplace

Made for: Claude Code.

Or install faos-analyst, the plugin that ships this one along with the rest of its 22 skills, 6 commands.

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-setup

README.md
[![agentmods](https://agentmods.dev/badge/skills/frank-luongt/faos-skills-marketplace/ab-test-setup/github.svg)](https://agentmods.dev/skills/frank-luongt/faos-skills-marketplace/ab-test-setup)
Your own site
<a href="https://agentmods.dev/skills/frank-luongt/faos-skills-marketplace/ab-test-setup"><img src="https://agentmods.dev/badge/skills/frank-luongt/faos-skills-marketplace/ab-test-setup/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ab-test-setup

Your own site · 80×15
<a href="https://agentmods.dev/skills/frank-luongt/faos-skills-marketplace/ab-test-setup"><img src="https://agentmods.dev/badge/skills/frank-luongt/faos-skills-marketplace/ab-test-setup.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,065 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 91% 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 $0.00000 $0.01065
Opus 5 $0.00000 $0.00532
Sonnet 5 $0.00000 $0.00213
Haiku 4.5 $0.00000 $0.00106

Measured 12d ago against content hash 858f4ff08ee4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

ab-test-setup 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 12d 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

91% identical to ab-test-setup — 39 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.

plugins/faos-analyst/skills/ab-test-setup/SKILL.md · 237 lines

How it starts

The opening of the file, as written. The whole thing — 237 lines — stays where its author put it; the contents beside it link to each section on GitHub.


name: ab-test-setup description: Structured guide for setting up A/B tests with mandatory gates for hypothesis, metrics, and execution readiness. Use when planning experiments, defining test hypotheses, calculating sample sizes, or validating A/B test designs. tags: [ab-testing, experimentation, cro]

A/B Test Setup

Purpose & Scope

Ensure every A/B test is valid, rigorous, and safe before a single line of code is written.

  • Prevents "peeking"
  • Enforces statistical power
  • Blocks invalid hypotheses

Pre-Requisites

You must have:

  • A clear user problem
  • Access to an analytics source
  • Roughly estimated traffic volume

Hypothesis Quality Checklist

A valid hypothesis includes:

  • Observation or evidence
  • Single, specific change
  • Directional expectation
  • Defined audience
  • Measurable success criteria

Hypothesis Lock (Hard Gate)

Before designing variants or metrics, you MUST:

  • Present the final hypothesis
  • Specify:
    • Target audience
    • Primary metric
    • Expected direction of effect
    • Minimum Detectable Effect (MDE)

Ask explicitly:

"Is this the final hypothesis we are committing to for this test?"

Do NOT proceed until confirmed.


Assumptions & Validity Check (Mandatory)

Explicitly list assumptions about:

  • Traffic stability
  • User independence
  • Metric reliability
  • Randomization quality
  • External factors (seasonality, campaigns, releases)

If assumptions are weak or violated:

  • Warn the user
  • Recommend delaying or redesigning the test

Test Type Selection

Choose the simplest valid test:

  • A/B Test - single change, two variants
  • A/B/n Test - multiple variants, higher traffic required
  • Multivariate Test (MVT) - interaction effects, very high traffic
  • Split URL Test - major structural changes

Default to A/B unless there is a clear reason otherwise.


Metrics Definition

Primary Metric (Mandatory)

Read the full file on GitHub · 237 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. 12d ago First seen · 237 lines · 0 tokens per session scan A 858f4ff08ee4

Subscribe to this mod's changes

ab-test-setup is a skill published in the GitHub repository frank-luongt/faos-skills-marketplace (33 stars, last pushed 2mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 1,065 tokens. A static security scan graded it A with 0 findings. It is 91% identical to ab-test-setup, differing in 39 lines, and is treated as a copy.

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