brainstorm-experiments-existing

An agent skill by phuryn, from phuryn/pm-skills. Tags: automation, brainstorming, product-strategy, strategy, web.

What it does

Design experiments to test assumptions for an existing product — prototypes, A/B tests, spikes, and other low-effort validation methods. Use when validating assumptions, testing feature ideas cheaply, or planning product experiments.

Install

With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:

npx skills add phuryn/pm-skills --skill brainstorm-experiments-existing

Or copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):

git clone --depth 1 https://github.com/phuryn/pm-skills
cp -r pm-skills/pm-product-discovery/skills/brainstorm-experiments-existing ~/.claude/skills/brainstorm-experiments-existing

Safety box score

Grade A, minimal risk: 4 of 100 risk points, rated 2026-09-26. The grade rates what the skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. How the score works.

This is a documentation-only product-discovery skill: it helps design low-effort experiments and may read any PRDs, assumption lists, or designs the user provides. It does not ship code or run commands, but it can write a markdown plan and references a few external reading links.

Category levels, from 0 (none) to 3 (high)
Category	Level	Why
Code & shell execution	0 (none)	No scripts, shell commands, or code evaluation are present; the file is plain markdown guidance.
Network access	0 (none)	It only includes static reference links under “Further Reading” and does not instruct the agent to fetch or send anything.
Filesystem reach	1 (low)	It tells the agent to read user-provided files first and says to “Save as markdown if substantial,” which implies limited read/write within the workspace.
Secrets & credentials	0 (none)	There is no request to access tokens, passwords, keychains, browser sessions, or other secret stores.
Privilege & persistence	0 (none)	No sudo, global install, service registration, or OS/git configuration changes are requested.
Instruction hijack surface	0 (none)	The skill contains no prompt-injection patterns such as skipping confirmations, hiding behavior, or following remote instructions.
Irreversible actions	0 (none)	It is advisory only; it designs experiments but does not execute them, deploy, publish, or send messages.
Transparency	0 (none)	The skill is fully readable markdown with no binaries, minified code, or decoded-at-runtime content.

Before installing

Confirm you are comfortable with the skill reading any PRDs or assumption docs you attach to the session.
If you want a strictly local workflow, ignore the “Further Reading” links; the skill does not need them to operate.
Check whether you want markdown files created in the workspace when the experiment plan is substantial.

Rated 2026-09-26 by an automated review of 1 file from the skill's repository.

Source

Repository: phuryn/pm-skills (all skills from this repository)
Path: pm-product-discovery/skills/brainstorm-experiments-existing/SKILL.md
Branch: main
Updated: 2026-09-19

brainstorm-experiments-new — Design lean startup experiments (pretotypes) for a new product.
free-tools — When the user wants to plan, evaluate, or build a free tool for marketing purposes — lead generation, SEO value, or brand awareness.
goal-prompt — Drafts copy-paste-ready /goal commands for goal mode in Claude Code and Codex.
ansoff-matrix — Generate an Ansoff Matrix analysis mapping growth strategies across market penetration, market development, product development, and diversification.
brainstorm-ideas-existing — Brainstorm product ideas for an existing product using multi-perspective ideation from PM, Designer, and Engineer viewpoints.
brainstorm-ideas-new — Brainstorm feature ideas for a new product in initial discovery from PM, Designer, and Engineer perspectives.