experiment-brief

experiment-brief is a skill for Claude Code from ai-analyst-lab/ai-analyst. It costs 275 tokens per session (2,759 once invoked), scanned A, original, MIT.

A structured plan for a product experiment, including its hypothesis, main measure, safety measures, success conditions, and estimated duration. An A/B test compares different versions with data to see which performs better.

In plain words
What is it for?
Use it when proposing an experiment, A/B test, or product validation effort to define what will be tested, how success will be measured, and when to ship, stop, or revise.
Why use it?
It turns a vague idea to test a change into a defined plan before the experiment is designed, reducing unclear goals and missing decision rules.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: reads .claude/ paths.

Good fit Use it when proposing an experiment, A/B test, or product validation effort to define what will be tested, how success will be measured, and when to ship, stop, or revise.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ai-analyst-lab/ai-analyst/experiment-brief
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 ai-analyst-lab/ai-analyst --skill experiment-brief
Clone the repo
git clone --depth 1 https://github.com/ai-analyst-lab/ai-analyst

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 experiment-brief

README.md
[![agentmods](https://agentmods.dev/badge/skills/ai-analyst-lab/ai-analyst/experiment-brief/github.svg)](https://agentmods.dev/skills/ai-analyst-lab/ai-analyst/experiment-brief)
Your own site
<a href="https://agentmods.dev/skills/ai-analyst-lab/ai-analyst/experiment-brief"><img src="https://agentmods.dev/badge/skills/ai-analyst-lab/ai-analyst/experiment-brief/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 experiment-brief

Your own site · 80×15
<a href="https://agentmods.dev/skills/ai-analyst-lab/ai-analyst/experiment-brief"><img src="https://agentmods.dev/badge/skills/ai-analyst-lab/ai-analyst/experiment-brief.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 275 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,759 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 original No closer match found 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 $0.00275 $0.02759
Opus 5 $0.00138 $0.01380
Sonnet 5 $0.00055 $0.00552
Haiku 4.5 $0.00028 $0.00276

Measured 2d ago against content hash e47dc34ea1bb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-13, from the pricing page.

Security

Grade A, and why

experiment-brief 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 2d 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

Copies of this mod

1 near-identical copy found in the catalogue:

.claude/skills/experiment-brief/SKILL.md · 203 lines

How it starts

The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill: Experiment Brief

Purpose

Auto-generate a structured experiment brief when a user expresses intent to test something. This is the "think before you design" safety net — ensuring every experiment starts with a clear hypothesis, north star metric, guardrail metrics, success criteria, and duration estimate before the Experiment Designer agent runs.

When to Use

Apply this skill when:

  1. The user says "I want to test..." or "Let's experiment with..." or "Should we A/B test..." or any variant expressing intent to run an experiment
  2. Before invoking the Experiment Designer agent — the brief is a prerequisite input
  3. When an experiment request is vague — the user wants to test something but hasn't specified metrics, duration, or success criteria

This skill auto-fires on experiment intent detection. Do NOT wait to be asked.

Critical Requirements

The brief must be COMPLETE and ACTIONABLE:

  • No "TBD" placeholders — all decisions are made in the brief
  • No "Would you like me to..." deferral — do the work now
  • No missing thresholds — every guardrail has a number
  • No ambiguous success criteria — ship/kill/iterate conditions are specific
  • Always includes a VIABLE/MARGINAL/NOT_VIABLE feasibility flag

If the user provides baseline values, VALIDATE them by querying the data first. Correct misstatements with actual numbers before using them in the brief.

Instructions

What Is an Experiment Brief?

An experiment brief is a one-page document that captures the essential decisions BEFORE any statistical design work begins. It answers: What are we testing? Why? How will we know if it worked? What must we not break?

EXPERIMENT BRIEF
━━━━━━━━━━━━━━━━
WHAT:       What change are we testing?
WHY:        What business outcome do we expect?
HYPOTHESIS: We believe [change] will [impact metric] because [reason]
NORTH STAR: The ONE metric we're trying to move
GUARDRAILS: Metrics that must NOT degrade
SUCCESS:    What result would make us ship?
DURATION:   Rough estimate of how long we'd need to run

Read the full file on GitHub · 203 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. 2d ago First seen · 203 lines · 275 tokens per session scan A e47dc34ea1bb

Subscribe to this mod's changes

experiment-brief is a skill published in the GitHub repository ai-analyst-lab/ai-analyst (298 stars, last pushed 3d ago), licensed MIT. It adds 275 tokens to every session and 2,759 once invoked, about $0.0014 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-12.

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