# pmf-strategy

A skill for measuring product-market fit before you scale: the Sean Ellis test, vitamin vs painkiller diagnosis, and retention signals.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1100 installs · ★ 1062
- Author: kostja94
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/kostja94/marketing-skills/tree/HEAD/skills/strategies/launch/pmf/SKILL.md
- Updated: 2026-10-21
- HTML: https://affpapa.org/en/nevibecode/skills/pmf-strategy

## What it does

This skill walks through product-market fit validation and measurement. The core piece is the Sean Ellis test, which asks how users would feel if the product disappeared: 40% or more answering "very disappointed" counts as PMF, below 25% means significant changes, and 25–39% sits close to the line. The skill suggests surveying 40–50 active users and segmenting them, since one group can have PMF while another does not.

A second section separates painkillers from vitamins. A painkiller solves an urgent problem, a vitamin is nice to have. The author ties nearly all startup failures to vitamin problems and premature scaling, so the skill pushes you to confirm demand before spending on acquisition.

Output covers current signals, a vitamin-or-painkiller diagnosis, a validation plan built on interviews, pre-sells and metrics, plus a call on whether to iterate or scale. PMF is treated as continuous: markets shift, so you re-measure when entering a new segment. For SaaS and enterprise, procurement cycles and private deployment get factored in. Once validation is done, the author points to the separate gtm-strategy skill for go-to-market.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add kostja94/marketing-skills --skill pmf-strategy -a claude-code
```
```bash
npx skills add kostja94/marketing-skills --skill pmf -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/pmf/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/pmf/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add kostja94/marketing-skills --skill pmf -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/pmf/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add kostja94/marketing-skills --skill pmf -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/pmf/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install kostja94/marketing-skills pmf
```

2. **Manually: put the files in place**
- File: `.github/skills/pmf/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add kostja94/marketing-skills --skill pmf -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/kostja94/marketing-skills --path skills/strategies/launch/pmf
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/pmf/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add kostja94/marketing-skills --skill pmf -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/kostja94/marketing-skills/tree/HEAD/skills/strategies/launch/pmf/SKILL.md

## When to use it
- measure product-market fit with the Sean Ellis test
- tell a painkiller problem from a vitamin one
- read retention and churn as PMF signals
- check demand before spending on paid acquisition
- decide between iterating and scaling

## Example prompts
- run pmf-strategy: I want to measure PMF for our SaaS
- walk me through the Sean Ellis test and score the very disappointed share
- diagnose whether we're a vitamin or a painkiller, and what to do next

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 1c946e93c2e2f7f7.

BEGIN THIRD-PARTY FILE 1c946e93c2e2f7f7
```text
---
name: pmf-strategy
description: When the user wants to validate product-market fit, measure PMF, or plan before scaling. Also use when the user mentions "PMF," "product-market fit," "product market fit," "Sean Ellis test," "very disappointed," "vitamin vs painkiller," "PMF validation," "premature scaling," or "validate before scale." For GTM after validation, use gtm-strategy.
metadata:
  version: 1.1.1
---

# Strategies: Product-Market Fit

Guides product-market fit (PMF) validation and measurement. PMF occurs when a product precisely meets market needs, creating widespread demand. ~99% of startups fail primarily due to PMF issues (vitamin problems, premature scaling). Use this skill when validating before scaling, measuring PMF, or diagnosing traction problems.

**When invoking**: On **first use**, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On **subsequent use** or when the user asks to skip, go directly to the main output.

## Definition

**Product-market fit** (Marc Andreessen): "Being in a good market with a product that can satisfy that market."

**Signals**: Customers buying rapidly; usage growing; word-of-mouth spreading organically; high retention, low churn.

## Sean Ellis 40% Test

**Question**: "How would you feel if you could no longer use [product]?"

| Response | Meaning |
|----------|---------|
| **Very disappointed** | Strong PMF signal |
| Somewhat disappointed | — |
| Not disappointed | — |
| N/A – I no longer use | — |

**Threshold**: 40%+ answering "very disappointed" = PMF achieved. Below 40% = iterate.

| Score | Action |
|-------|--------|
| **Below 25%** | Significant changes needed |
| **25–39%** | Close to PMF; iterate and improve |
| **40%+** | PMF achieved |

**Best practice**: Survey 40–50 active users (used product 2+ times in last 14 days). Segment by user type—some segments may have PMF while others don't.

**Limitation**: Combine with retention curves, engagement, organic growth; avoid false positives in early stages.

## Vitamin vs Painkiller

| Type | Definition | Adoption |
|------|-------------|----------|
| **Painkiller** | Solves urgent, acute problems; users actively seek solutions | Fast adoption; high retention; willing to pay |
| **Vitamin** | Nice-to-have; incremental benefit; users can live without | Slow adoption; expensive marketing to succeed |

**~99% of failures**: Solving vitamin problems instead of real pain. Validate: Would users be genuinely inconvenienced if your product vanished?
```
END THIRD-PARTY FILE 1c946e93c2e2f7f7

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