Craft Experiment Design
amplitude/builder-skills
Write a hypothesis, define success metrics, and plan a holdout strategy.
Design statistically rigorous A/B tests and interpret experiment results.
Install Experiment Designer
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designer --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/experiment-designer .claude/skills/experiment-designer && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .claude/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designerType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designer --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/experiment-designer .agents/skills/experiment-designer && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .agents/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designer --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/experiment-designer .cursor/skills/experiment-designer && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .cursor/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/mohitagw15856/pm-claude-skills.git --path skills/experiment-designer--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designer --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/experiment-designer .gemini/skills/experiment-designer && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .gemini/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designerInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/experiment-designer .github/skills/experiment-designer && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .github/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install mohitagw15856/pm-claude-skills experiment-designer --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/experiment-designer .opencode/skills/experiment-designer && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "experiment-designer" agent skill from https://github.com/mohitagw15856/pm-claude-skills/tree/main/skills/experiment-designer into .opencode/skills/experiment-designer/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "experiment-designer", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
experiment-designer- GitHub stars
- 1.4k
- Token cost
- ~1.1k tokens
- SKILL.md length
- 522 words
- Files
- 1
- Skills in repo
- 1,348
- Repo updated
- First seen
- Licence
- MIT
At a glance
Design statistically rigorous A/B tests and interpret experiment results.
- Works in 2 steps: Experiment Design → Results Interpretation
- Asked to design an experiment
- SKILL.md covers Required Inputs, Two-Phase Process, Output Structure and Quality Checks, plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Experiment Designer is an agent skill from mohitagw15856/pm-claude-skills. Design statistically rigorous A/B tests and interpret experiment results. Use when asked to design an experiment, run an A/B test, calculate sample size, interpret test results, or assess whether an experiment was successful. Produces a complete experiment design with hypothesis, sample size, run time, success criteria, and risk flags — or a results interpretation with ship/iterate/kill recommendation.
Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Research & Science, covering Experimental design and A/B testing. The repository describes itself as: 1255 professional Agent Skills for Claude, ChatGPT, Gemini, Cursor & Codex — PRDs, postmortems, leases, medical bills, layoffs, go-bags, new countries. Plain markdown, MIT, in… The licence is MIT.
When your agent uses it
- Asked to design an experiment
- Run an A/B test
- Calculate sample size
- Interpret test results
Example prompts
- “/experiment-designer”
Workflow steps
2 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 1cbf1f0. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Experiment Designer loads about 1.1k tokens when it runs. Until then it costs about 106 tokens; SKILL.md has 522 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from mohitagw15856/pm-claude-skills at commit 1cbf1f0, republished under its MIT licence (© mohitagw15856). 522 words, ~1,071 tokens.
Download SKILL.mdSave it as
.claude/skills/experiment-designer/SKILL.md (or your agent's skills folder).- name
- experiment-designer
- description
- Design statistically rigorous A/B tests and interpret experiment results. Use when asked to design an experiment, run an A/B test, calculate sample size, interpret test results, or assess whether an experiment was successful. Produces a complete experiment design with hypothesis, sample size, run time, success criteria, and risk flags — or a results interpretation with ship/iterate/kill recommendation.
Experiment Designer Skill
Produce rigorous experiment designs from product hypotheses, and interpret results with statistical and practical significance — so you can defend every decision to a sceptical engineering lead or data scientist.
Required Inputs
Ask the user for these if not provided: For experiment design:
- Hypothesis (what change, what metric, what expected movement)
- Current baseline metric value
- Minimum detectable effect (MDE) — the smallest lift worth caring about
- Available daily sample size
For results interpretation:
- Control and variant results (raw numbers or percentages)
- P-value or confidence interval
- Run duration (days)
- Any anomalies observed during the test
Two-Phase Process
Phase 1: Experiment Design
- Restate hypothesis as: "If we [change], we expect [metric] to [move by X%] because [reason]"
- Define control and variant clearly
- Select primary metric (one only) and secondary guardrail metrics (2-3 max)
- Calculate required sample size from MDE and baseline
- Estimate run time in days
- Set pre-defined success criteria before the test runs — no moving goalposts
- Flag design risks: novelty effects, seasonal confounds, multiple testing issues, network effects, sample ratio mismatch
Phase 2: Results Interpretation
- Assess statistical significance (p < 0.05 threshold)
- Assess practical significance: was the lift meaningful for the business, not just real?
- Interpret confidence intervals
- Investigate confounding factors
- Recommend: Ship / Iterate / Kill / Run follow-up test
- Validate — Confirm the test ran for the full planned duration. Flag if it was stopped early (peeking problem). Confirm sample ratio mismatch did not occur.
Output Structure
[Design or Results header based on phase]
Hypothesis: "If we [change], we expect [metric] to [move by X%] because [reason]"
Primary metric: [One metric only] Guardrail metrics: [2-3 max] Required sample size: [n per variant] Estimated run time: [days] Pre-defined success threshold: [specific number] Design risk flags: [any concerns]
Results (Phase 2 only): Statistical significance: [p-value and conclusion] Practical significance: [lift size vs. business threshold] Recommendation: Ship / Iterate / Kill / Follow-up — [rationale]
Show full SKILL.md (204 more words)Show less
Quality Checks
- Hypothesis specifies the change, the metric, the direction, and the reason
- Primary metric is singular — guardrail metrics are secondary
- Success criteria are defined before the test launches (not after seeing results)
- Test was not stopped early (or flagged clearly if it was)
- Practical significance assessed separately from statistical significance
- Sample ratio mismatch is checked in results interpretation
Anti-Patterns
- Do not define success criteria after seeing preliminary results — post-hoc success definitions are HARKing (Hypothesising After Results are Known) and invalidate the experiment
- Do not stop a test early because the result looks significant — early stopping dramatically inflates false positive rates; the test must run to the planned sample size
- Do not treat statistical significance as the same as practical significance — a p < 0.05 result with a 0.1% lift is real but may not be worth shipping
- Do not run the same experiment on the same population multiple times without correction — multiple testing inflates the chance of a false positive proportionally
- Do not use more than one primary metric — multiple primary metrics require multiple hypothesis corrections and make the ship/kill decision ambiguous
Example Trigger Phrases
- "Design an experiment."
- "Run an A/B test."
- "Calculate sample size."
- "Interpret test results."
- "Assess whether an experiment was successful."
© mohitagw15856, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/experiment-designer of mohitagw15856/pm-claude-skills.
Open the folder on GitHubat commit 1cbf1f0
Compare with similar skills
Experiment Designer next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Experiment Designer this skillmohitagw15856/pm-claude-skills | 1.4k | — | ~1.1k | Automated safety check: Pass | MIT | |
| Craft Experiment Designamplitude/builder-skills | 159 | — | ~522 | Automated safety check: Pass | None | |
| Hypothesis Testerjeremylongshore/tons-of-skills-marketplace | 2.8k | — | ~2.6k | Automated safety check: Pass | MIT | |
| Data Scientistmagnus919/hermes-profiles | 289 | — | ~3.3k | Automated safety check: Pass | MIT | |
| Data Scientistmagnus919/agent-skills | 119 | — | ~4.1k | Automated safety check: Pass | MIT | |
| Measure Experiment Designproduct-on-purpose/pm-skills | 716 | — | ~1.1k | Automated safety check: Pass | Apache-2.0 |
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Related
Categories
Questions about Experiment Designer
What does Experiment Designer do?
Design statistically rigorous A/B tests and interpret experiment results. Experiment Designer is an agent skill from mohitagw15856/pm-claude-skills. Design statistically rigorous A/B tests and interpret experiment results.
When should I use Experiment Designer?
Experiment Designer fits situations like: asked to design an experiment; run an A/B test; calculate sample size; interpret test results.
How do I install Experiment Designer in Claude Code?
Run `npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a claude-code`. Or copy the skill folder (skills/experiment-designer in mohitagw15856/pm-claude-skills) into .claude/skills/experiment-designer in your project. Claude Code loads it when a task matches its description.
How do I install Experiment Designer in Codex?
Run `npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a codex`. Or copy the skill folder (skills/experiment-designer in mohitagw15856/pm-claude-skills) into .agents/skills/experiment-designer in your project. Codex loads it when a task matches its description.
Can I use Experiment Designer in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add mohitagw15856/pm-claude-skills --skill experiment-designer -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/experiment-designer, .gemini/skills/experiment-designer, .github/skills/experiment-designer and .opencode/skills/experiment-designer in your project.
What does Experiment Designer need to run?
SKILL.md names no scripts, command-line tools or credentials: Experiment Designer is instructions for the agent only.
Does Experiment Designer access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Experiment Designer safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Experiment Designer use?
Experiment Designer is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Experiment Designer use?
About 1.1k tokens (SKILL.md is roughly 4.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Experiment Designer?
Skills that share tags, products or a category with Experiment Designer: Craft Experiment Design (amplitude/builder-skills, 159 stars), Hypothesis Tester (jeremylongshore/tons-of-skills-marketplace, 2.8k stars), Data Scientist (magnus919/hermes-profiles, 289 stars) and Data Scientist (magnus919/agent-skills, 119 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Experiment Designer?
mohitagw15856 (a GitHub user) maintains it in mohitagw15856/pm-claude-skills, which has 1,434 GitHub stars. The repository holds 1,348 skills in this directory. The repository was last updated on October 9, 2026.
Source: mohitagw15856/pm-claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.