# market-sizing

Sizes a market, segment or opportunity with stated assumptions and uncertainty. Covers TAM/SAM/SOM and scenario comparisons.

- skill · `type=skill` · Codex, ChatGPT · 3 installs · ★ 7604
- Author: Data Analytics Maintainers · official OpenAI repository
- License: LicenseRef-Proprietary · policy=link-only · description only; the file stays with the author
- Source: https://github.com/openai/plugins/tree/HEAD/plugins/data-analytics/skills/market-sizing/SKILL.md
- Updated: 2026-10-08
- HTML: https://affpapa.org/en/nevibecode/skills/market-sizing

## What it does

The skill walks from framing to sensitivity testing. It starts by drawing the boundary: what is being sized, where and when it applies, who counts as part of the market, and which unit measures it — spend, revenue, volume or population. Then it picks an approach: top-down from aggregate data, bottom-up from observable units, or value-based from the value created.

Next it gathers sources for the inputs that matter most. Sourced facts, inferred estimates and judgement calls stay separate, and every major input carries a visible path: structured data, company docs, a public source or a proxy assumption. Derived values trace back to formulas or code, so the model can be recalculated. `$jupyter-notebooks` handles calculations, `$Spreadsheets` builds a workbook, `$visualize-data` draws the chart.

When a required source of truth is missing, the skill stops that path instead of swapping in a weaker substitute. A missing input that would shift the answer gets a question; otherwise the skill states a reasonable assumption and moves on. Thin inputs come back as ranges, not a single number.

## Install

### Codex (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add openai/plugins --skill market-sizing -a codex
```

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

### Claude Code

1. **Skills CLI (Vercel)**
```bash
npx skills add openai/plugins --skill market-sizing -a claude-code
```

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

### Cursor

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

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install openai/plugins market-sizing
```

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

### Gemini CLI

**Platform CLI**
```bash
gemini skills install https://github.com/openai/plugins --path plugins/data-analytics/skills/market-sizing
```

### Windsurf (Devin Desktop)

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

### 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/openai/plugins/tree/HEAD/plugins/data-analytics/skills/market-sizing/SKILL.md

## When to use it
- size TAM, SAM and SOM for a new product
- compare the scale of two candidate markets
- build an estimate from warehouse data plus public benchmarks
- find which assumptions move the estimate most
- keep facts and guesses apart in a market model

## Example prompts
- Size TAM and SAM for our segment and list the assumptions separately
- Build a bottom-up market model from warehouse data and test its sensitivity
- Compare two candidate directions and tell me what is missing for confidence

## Similar
- [discover-market-sizing](https://affpapa.org/en/nevibecode/skills/discover-market-sizing.md) — skill · 619 installs
- [market-opportunity](https://affpapa.org/en/nevibecode/commands/market-opportunity.md) — command · ★ 41823
- [market-sizing-analysis](https://affpapa.org/en/nevibecode/skills/market-sizing-analysis.md) — skill · 11715 installs
- [tam-sam-som-calculator](https://affpapa.org/en/nevibecode/skills/tam-sam-som-calculator.md) — skill · 2300 installs
- [data-analyst](https://affpapa.org/en/nevibecode/skills/borghei-data-analyst.md) — skill · 605 installs
- [sales-market-sizing](https://affpapa.org/en/nevibecode/skills/sales-market-sizing.md) — skill · 26400 installs

## Other versions with the same name
- [market-sizing · phuryn](https://affpapa.org/en/nevibecode/skills/phuryn-market-sizing.md) — 3000 installs

From the same set: [openai/plugins](https://affpapa.org/en/nevibecode/by/openai/plugins.md) — 420 cards

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md