Marketplace Scam Checker

# Marketplace Scam Checker

A free agent kit for anyone buying or selling on Facebook Marketplace, Craigslist, OfferUp, eBay, Mercari, Poshmark, Depop, Vinted, Etsy or in buy/sell groups. Paste the conversation. You get back:
- a risk level: Low, Medium, High or Stop;
- each warning sign, quoted from the conversation and matched to a known scam pattern;
- the safe next steps and a safe reply (or "block and report");
- safety basics for this deal (where to meet, how to pay, what to check);
- if you've already sent money, a code or details: urgent steps in order, and where to report.

Twenty patterns are covered, including verification-code (Google Voice) scams, overpayment and "my mover will pick up", fake Zelle "business account" emails, deposits before viewing, fake escrow, hijacked accounts and phishing links.

Made by AgentLoomX (https://agentloomx.com). Version 1.0.0.

## Who it's for

- People selling locally on Marketplace, OfferUp or Craigslist.
- Buyers looking at deals that seem too good.
- Resellers training a helper on what to watch for.
- Admins of buy/sell groups who want to explain scams to members.

## What's inside

```
marketplace-scam-check-agent/
  instructions.md                  the agent's instructions (system prompt)
  knowledge/scam-patterns.md       20 patterns for buyers and sellers, with tells and safe responses
  knowledge/if-you-got-scammed.md  urgent steps, where to report, evidence to keep
  starters.md                      conversation starters
  claude-code/agents/marketplace-scam-check-agent.md   Claude Code subagent version
  examples/example-1.md            worked example: three buyers for a game console
  README.md, CHANGELOG.md, LICENSE.txt
```

## Setup

### ChatGPT (GPT Builder)
1. In ChatGPT, go to Explore GPTs, then Create.
2. Open the Configure tab. Name it "Marketplace Scam Checker".
3. Paste the full text of `instructions.md` into Instructions.
4. Under Knowledge, upload the files in `knowledge/`.
5. Add the conversation starters from `starters.md`, then save.

### Claude (Projects)
1. In Claude, create a new Project.
2. Paste the full text of `instructions.md` into the project instructions.
3. Add the files in `knowledge/` to the project knowledge.
4. Start a chat in the project.

### Google Gemini (Gems)
1. In Gemini, open Gems and create a new Gem.
2. Paste the full text of `instructions.md` into the instructions box.
3. Add the files in `knowledge/` as knowledge files, then save.

### Claude Code
1. Copy `claude-code/agents/marketplace-scam-check-agent.md` to `~/.claude/agents/` (all projects) or `<project>/.claude/agents/` (one project).
2. Optional: copy the `knowledge/` folder into your project, for example `docs/marketplace-scam-check-agent/knowledge/`. The subagent looks for `**/marketplace-scam-check-agent/knowledge/*.md`.
3. Ask: "Use the marketplace-scam-check-agent subagent to check the buyer conversations in messages/console-sale.md."

## Usage examples

- "Is this buyer real? Here's the conversation."
- "The seller wants a $100 deposit by Zelle before I see the couch."
- "I read a code to someone. What now?"
- "Give me safe local pickup rules for selling a phone."

See `examples/example-1.md` for a full run.

## How to customize

- **New patterns:** add scams you've seen locally to `knowledge/scam-patterns.md`, with their tells.
- **Your country:** replace the US reporting links in `knowledge/if-you-got-scammed.md` with your country's services.

## Limitations

- It can't verify people, payments, links or listings. It matches the conversation against known patterns.
- It isn't legal or financial advice. For losses, your bank or payment provider and the police can act.
- Reporting links cover the US. Outside the US, use your national fraud reporting service.

## Support

Questions or problems? Use "Ask a question" on this product's AgentLoomX listing page.

## License

AgentLoomX Standard License. See `LICENSE.txt`.