Is the Hypothesis Design skill free?

Yes. The skill itself is free from itseffi/agentic-os. SkillProof publishes the install command and an independent test verdict at no cost.

What is the Hypothesis Design SkillProof Score?

9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 5/5.

How do I install Hypothesis Design?

Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.

Can I use Hypothesis Design with Cursor, Copilot, Gemini CLI, Codex or other AI tools?

The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.

Hypothesis Design

Forces a 5-part testable hypothesis statement instead of a vague A/B test guess

by itseffi · itseffi/agentic-os

Tested · Works

Install — copy the command Download source ↗

Test report

Verdict: Tested · Works
Score: 9.2/10
Tested: Jul 13, 2026
Environment: Claude Code 2.x (agent harness)
Upstream re-checked: Aug 10, 2026 · 64cdce6

Ran a signup-form-shortening experiment through it: baseline produced a one-line guess, the skill forced a guardrail metric (activation rate) and a sample-size estimate the baseline skipped entirely.

Scored on four weighted criteria — install, triggering, output vs. baseline, docs. How scoring works

Installs cleanly 5/5
Triggers reliably 5/5
Output vs. baseline 8/10
Docs & honesty 5/5

What Hypothesis Design does

Turns a fuzzy product problem into a falsifiable hypothesis with action, outcome, direction, users, and conditions, plus a measurement plan and narrative check. Use when scoping an A/B test or experiment before building it, not when analyzing results already collected.

How to install Hypothesis Design

git clone https://github.com/itseffi/agentic-os
cd agentic-os
mkdir -p ~/.claude/skills
cp -r .agents/skills/hypothesis-design ~/.claude/skills/hypothesis-design

Skills live in ~/.claude/skills/ (global) or .claude/skills/ (per-project). Restart Claude Code after installing.

Commands — how to trigger Hypothesis Design

/hypothesis-design Forces a 5-part testable hypothesis statement instead of a vague A/B test guess

It also activates on plain-language prompts like these:

Help me write a proper five-part hypothesis before we build this A/B test
I have a vague product problem, turn it into a falsifiable test hypothesis
Before scoping this experiment, define outcome, direction, users, conditions

Frequently asked questions

Is the Hypothesis Design skill free?: Yes. The skill itself is free from itseffi/agentic-os. SkillProof publishes the install command and an independent test verdict at no cost.
Does Hypothesis Design work with Claude Code?: We tested it with Claude Code 2.x (agent harness) on Jul 13, 2026. Verdict: Tested · Works. Ran a signup-form-shortening experiment through it: baseline produced a one-line guess, the skill forced a guardrail metric (activation rate) and a sample-size estimate the baseline skipped entirely.
What is the Hypothesis Design SkillProof Score?: 9.2/10 — installs cleanly 5/5, triggers reliably 5/5, output vs. baseline 8/10, docs & honesty 5/5.
How do I install Hypothesis Design?: Copy the install command from this page, run it in your terminal, and restart Claude Code. Skills live in ~/.claude/skills/ (global) or .claude/skills/ inside a project.
Can I use Hypothesis Design with Cursor, Copilot, Gemini CLI, Codex or other AI tools?: The SKILL.md format is native to Claude (Claude Code, Desktop, claude.ai). The instructions inside adapt to other assistants: Cursor rules, GitHub Copilot instructions, Windsurf rules, Custom GPTs, AGENTS.md for OpenAI Codex, and GEMINI.md for Google Gemini CLI — our conversion guides cover each, and the free converter on the tools page does the wrapping for you.