How do I install the Marketplace skill?

Run npx skillmds@latest add modbender/marketplace in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Marketplace safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Marketplace?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Marketplace free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Marketplace?

modbender (@modbender) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Marketplace by modbender — Agent Skill

Name: Marketplace
Rating: 4.5 (4 reviews)
Author: modbender

File contents

Architecture

Role-based guidance for marketplace participation. Load relevant file based on user's role.

marketplace/
├── buyer.md      # Price comparison, scam detection, negotiation
├── seller.md     # Listing creation, pricing, platform rules
├── builder.md    # Marketplace creation, economics, liquidity
├── arbitrage.md  # Price gaps, ROI calculations, ToS risks
└── compliance.md # Tax obligations, legal pitfalls, bans

Quick Reference

Role	File	When to Load
Buying items	`buyer.md`	Comparing prices, spotting scams, negotiating
Selling items	`seller.md`	Creating listings, pricing, handling buyers
Building marketplace	`builder.md`	Designing platform, economics, payments
Arbitrage/Reselling	`arbitrage.md`	Finding price gaps, calculating true ROI
Legal/Tax questions	`compliance.md`	Tax nexus, ToS violations, suspensions

Core Rules

1. Platform-Specific, Never Generic

Each platform has unique fees, rules, and dynamics
eBay auction ≠ Amazon Buy Box ≠ FB Marketplace negotiation
ALWAYS specify which platform advice applies to

2. Total Cost, Not Sticker Price

Include: platform fees, shipping, taxes, return costs
Amazon referral fee varies 8-45% by category
eBay 13%+ Poshmark 20%+ Mercari varies

3. Scam Pattern Recognition

Stock photos on local marketplaces = red flag
"Ship to my address, I'll pay extra" = triangulation fraud
Payment outside platform = no protection
New account + high-value item + urgency = likely scam

4. Pricing Research = SOLD, Not Listed

Listed prices mean nothing—items don't sell at listed price
Always research completed/sold listings
Factor in condition: "Good" vs "Very Good" = 30% price difference

5. Suspension Risks Are Real

Amazon ODR >1% = account death
Review manipulation = permanent ban
IP complaints from brands = immediate suspension
Multiple accounts = instant termination

6. Fee Complexity

Never estimate fees—calculate exactly:

Amazon: referral + FBA + storage + return processing + advertising
eBay: final value (category-specific) + promoted listings + payment
Factor returns into margin (15-30% in some categories)

7. Real-Time Data Required

Never quote prices from memory/training data
Inventory and pricing change hourly
Competitor stock levels affect optimal pricing
Always verify current marketplace state before advising

---name: marketplacedescription: Navigate online marketplaces as buyer, seller, or builder with platform comparison, listing optimization, and scam detection.--- ## Architecture Role-based guidance for marketplace participation. Load relevant file based on user's role. ``` marketplace/ ├── buyer.md # Price comparison, scam detection, negotiation ├── seller.md # Listing creation, pricing, platform rules ├── builder.md # Marketplace creation, economics, liquidity ├── arbitrage.md # Price gaps, ROI calculations, ToS risks └── compliance.md # Tax obligations, legal pitfalls, bans ``` ## Quick Reference | Role | File | When to Load | |------|------|--------------| | Buying items | `buyer.md` | Comparing prices, spotting scams, negotiating | | Selling items | `seller.md` | Creating listings, pricing, handling buyers | | Building marketplace | `builder.md` | Designing platform, economics, payments | | Arbitrage/Reselling | `arbitrage.md` | Finding price gaps, calculating true ROI | | Legal/Tax questions | `compliance.md` | Tax nexus, ToS violations, suspensions | ## Core Rules ### 1. Platform-Specific, Never Generic - Each platform has unique fees, rules, and dynamics - eBay auction ≠ Amazon Buy Box ≠ FB Marketplace negotiation - ALWAYS specify which platform advice applies to ### 2. Total Cost, Not Sticker Price - Include: platform fees, shipping, taxes, return costs - Amazon referral fee varies 8-45% by category - eBay 13%+ Poshmark 20%+ Mercari varies ### 3. Scam Pattern Recognition - Stock photos on local marketplaces = red flag - "Ship to my address, I'll pay extra" = triangulation fraud - Payment outside platform = no protection - New account + high-value item + urgency = likely scam ### 4. Pricing Research = SOLD, Not Listed - Listed prices mean nothing—items don't sell at listed price - Always research completed/sold listings - Factor in condition: "Good" vs "Very Good" = 30% price difference ### 5. Suspension Risks Are Real - Amazon ODR >1% = account death - Review manipulation = permanent ban - IP complaints from brands = immediate suspension - Multiple accounts = instant termination ### 6. Fee Complexity Never estimate fees—calculate exactly: - Amazon: referral + FBA + storage + return processing + advertising - eBay: final value (category-specific) + promoted listings + payment - Factor returns into margin (15-30% in some categories) ### 7. Real-Time Data Required - Never quote prices from memory/training data - Inventory and pricing change hourly - Competitor stock levels affect optimal pricing - Always verify current marketplace state before advising

Frequently asked questions

Marketplace