used-car-finder

A Claude skill that helps you shop for a reliable used car on Facebook Marketplace. It filters out curbstoners, scams, and money-pit models; reads Carfax reports; identifies trim from photos; estimates fair value; and builds defect-anchored negotiation cases.

What this is

A skill, not a scraper. It teaches Claude how to evaluate a Marketplace listing the way a skeptical friend who knows cars would. You paste listings, photos, and Carfax PDFs into a conversation, and Claude walks you through the buy/walk decision.

Why this exists

Roughly 1 in 3 of the most appealing-looking listings on Facebook Marketplace have a significant red flag visible only in the body text or the seller's profile. Spotting these takes practice. This skill packages that practice.

The judgment framework comes from a real used-car search in 2026: a single buyer evaluating ~2,200 listings in a single metro, eventually shortlisting ~12 verified picks. The patterns generalize.

Installation

As a Claude Code skill

Clone this repo into your ~/.claude/skills/ directory:

cd ~/.claude/skills
git clone https://github.com/pjdoland/used-car-finder.git

The skill activates automatically when you ask Claude for help with used-car shopping in a Claude Code session.

Used by itself

You can also paste the contents of SKILL.md into any Claude conversation (Claude.ai, Claude Code, or the API). The reference files in references/ are pulled on demand.

Optional: Playwright MCP (recommended)

If you install the Playwright MCP server, the skill can drive a browser for you: navigate Marketplace search results, open listings, click into seller profiles, and apply the curbstoner check without you pasting screenshots. The skill detects Playwright at runtime; without it, you paste listings manually and everything else works the same.

To install Playwright MCP for Claude Code:

claude mcp add playwright -- npx -y @playwright/mcp@latest

You will need to be logged into Facebook in the browser Playwright controls. The skill does not handle credentials and will pause if FB challenges the session.

How to use it

The skill walks you through four stages:

1. Intake. Claude asks your metro, budget, body-style preferences, family situation, mechanical comfort, and belt-tolerance.
2. Search and filter. You paste listings (URLs or screenshots); Claude classifies them as Tier 1 / Tier 2 / Watch / Kill.
3. Verify and evaluate. On a specific car, Claude walks the curbstoner check, reads the Carfax, identifies trim from photos, and produces a PPI checklist.
4. Close. Claude builds a defect-anchored negotiation case and sets up insurance coverage.

Try: "Help me find a reliable used car under $7,000 in [your metro]."

Layout

SKILL.md                         main skill file (loaded by Claude)
references/
  reliable-makes.md              tier list of makes/models
  curbstoner-playbook.md         seller-profile rubric
  scam-patterns.md               body-text red flags
  carfax-reading.md              how to read a Carfax PDF
  trim-id-guide.md               identifying trim from photos
  ppi-checklist.md               pre-purchase inspection
  timing-chain-vs-belt.md        engine reference
  negotiation-framework.md       defect-anchored offers
  insurance-by-acv.md            coverage by vehicle value
examples/
  example-1-good-listing.md      green-flag listing walkthrough
  example-2-curbstoner.md        curbstoner detection walkthrough
  example-3-scam.md              wire-fraud scam walkthrough
tests/
  self-test.md                   regression tests for the skill

Scope and limitations

• Facebook Marketplace only. Craigslist, AutoTrader, CarGurus, and dealer sites have different scam patterns and seller dynamics.
• US market, US insurance. Some references (state inspection, insurance carriers, title-branding rules) assume US conventions.
• Private-party purchases. Dealer purchases follow different rules.
• Under ~$15K. The judgment framework is calibrated for older, higher-mileage cars where reliability matters more than features. For newer or more expensive cars, traditional consumer-research approaches (Consumer Reports, Edmunds) are also useful.

Self-test

tests/self-test.md contains 5 synthetic listings with expected verdicts. Run them past the skill periodically to catch regressions if you modify the references.

Contributing

PRs welcome. The kind of contributions that help:

• New scam patterns you've encountered on Marketplace
• Model-specific known issues for cars not yet in reliable-makes.md
• Trim-identification tells for brands not yet documented
• Regional notes for state-specific insurance or title rules
• Additional self-test cases

License

MIT. See LICENSE.

Disclaimer

This skill provides general guidance for evaluating used-car listings. It is not a substitute for a professional pre-purchase inspection, a licensed mechanic's opinion, or legal advice. The author is not responsible for any purchase decisions made using this skill.