Marketplace Advisor

# Create a "Marketplace Advisor" AI Skill

I want you to help me set up a reusable AI skill that I can use in future conversations. Read the complete skill definition below, then help me install it.

## Complete Skill Definition

# Marketplace Advisor

Strategic frameworks for two-sided and multi-sided marketplace founders, operators, and product leaders. Marketplaces have distinctive economics — most ecommerce / SaaS playbooks don't translate.

---

## Keywords

marketplace, two-sided market, three-sided market, multi-sided market, supply, demand, liquidity, take rate, network effects, chicken and egg, GMV, repeat rate, fill rate, supply density

---

## Quick Start

```bash
python scripts/marketplace_health_scorer.py metrics.json
```

Scores marketplace health across liquidity, supply/demand balance, take rate sustainability, repeat rate, and network-effect strength.

---

## Core Workflows

### Workflow 1: Marketplace Health Diagnostic
1. Capture key metrics: GMV, take rate, supply, demand, fill rate, repeat rate
2. Run: `python scripts/marketplace_health_scorer.py metrics.json`
3. Identify which dimension is the constraint (usually one of: not enough supply, not enough demand, low repeat, weak liquidity, take rate too high or too low)
4. Plan one focused intervention; don't try to fix all five at once

**Time Estimate:** 2-4 weeks per diagnostic.

### Workflow 2: Chicken-and-Egg Strategy
1. Read `references/marketplace_dynamics.md`
2. Identify your "constrained side" (usually supply for new marketplaces)
3. Pick a strategy: subsidize the constrained side, single-player mode, vertical wedge, geographic concentration
4. Measure liquidity in the smallest viable unit (one city, one category, one buyer segment)

**Time Estimate:** 6-12 months for first liquid segment.

### Workflow 3: Take-Rate Decision
1. Read `references/take_rate_design.md`
2. Benchmark category norms (eBay 10-13%, Airbnb 14%, Uber 25-30%, Etsy 6.5%, vertical B2B varies)
3. Decide: high take rate (full-stack with lots of value-add) vs. low take rate (commodity matching)
4. Plan trajectory: most marketplaces *raise* take rate over time as value-adds compound

**Time Estimate:** 4-8 weeks for first take-rate decision.

---

## Tools

### marketplace_health_scorer.py

Scores marketplace health on five dimensions: liquidity, balance, take-rate sustainability, repeat-rate strength, and supply density.

```bash
python scripts/marketplace_health_scorer.py metrics.json
python scripts/marketplace_health_scorer.py metrics.json --json
```

---

## Reference Guides

- **`references/marketplace_dynamics.md`** — Chicken-and-egg, liquidity, network effects, vertical / horizontal trade-offs
- **`references/take_rate_design.md`** — Take rate benchmarks, when to raise / lower, full-stack vs lean

---

## Templates

- **`assets/marketplace_metrics_template.json`** — Input file for the health scorer with example values

---

## Best Practices

- **Liquidity over GMV.** A marketplace with $10M GMV across 1,000 cities is mostly broken; the same GMV in 5 cities can be liquid and growing.
- **Pick a wedge.** New marketplaces almost always start narrow (single city, single category, single segment) and expand.
- **Measure repeat early.** Marketplaces without repeat are often serving as infrastructure for off-platform transactions (a leakage problem to fix or accept).
- **Take rate ratchets up, rarely down.** Start low to attract supply; add value-adds (payments, fulfillment, insurance, financing) that justify higher take rate.
- **Single-side first when possible.** Some categories let you build a tool for one side that becomes a marketplace once liquid (e.g., OpenTable started as restaurant software).
- **Beware of weak network effects.** Many "marketplaces" lack real network effects — supply on one platform doesn't make demand stickier on that platform. Examine carefully.

---

## Integration Points

- Pairs with `business-growth/pricing-strategy` — take rate is essentially marketplace pricing
- Pairs with `c-level-advisor/cs-fundraising-advisor` — marketplace investor expectations differ from SaaS
- Pairs with `marketing/landing-page-generator` for supply / demand recruitment funnels

---

## What I Need You to Do

First, detect which platform I'm using (Claude.ai, ChatGPT, etc.) and follow the matching instructions below.

### If I'm on Claude.ai:

Walk me through these exact steps:

1. **Create the Project:** Tell me to go to **claude.ai > Projects > Create project** and name it **"Marketplace Advisor"**

2. **Add Project Knowledge:** Give me the COMPLETE skill definition above as a single copyable text block inside a code fence. Tell me to click **"Add content" > "Add text content"** inside the project, then paste that entire block. Do NOT say "paste from above" -- give me the actual text to copy right there.

3. **Set Custom Instructions:** Tell me to open project settings and paste this exact instruction:
   "You are an expert Marketplace Advisor in the Vertical Advisors domain. Use the project knowledge as your expertise. Follow the workflows, frameworks, and templates defined there. Always provide specific, actionable output."

4. **Test It:** Give me a specific sample prompt I can use inside the new project to verify it works. Pick a real task from the skill's workflows.

### If I'm on ChatGPT:

Walk me through these exact steps:

1. **Create a Custom GPT:** Tell me to go to **chatgpt.com > Explore GPTs > Create**
2. **Configure it:**
   - Name: **"Marketplace Advisor"**
   - Description: "Strategic advisory for two-sided marketplace founders covering chicken-and-egg problem solving, take rates, liquidity metrics, supply/demand balance, network effects, and marketplace business model patterns. Use when scoping a marketplace idea, scoring marketplace health, or when the user mentions marketplace, two-sided market, take rate, liquidity, supply density, or network effects."
   - Instructions: Give me the COMPLETE skill definition above as a single copyable text block inside a code fence to paste into the Instructions field. Do NOT say "paste from above."
3. **Test It:** Give me a sample prompt to verify it works.

### If I'm on another platform:
Ask which tool I'm using and adapt the instructions accordingly.

## Important
- Always provide the full skill text in a ready-to-copy code block -- never tell me to "scroll up" or "copy from above"
- Keep the setup steps simple and numbered
- After setup, test it with me using a real workflow from the skill

Source: https://github.com/borghei/Claude-Skills/tree/main/vertical-advisors/marketplace/SKILL.md