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CS-06 AI / Buying

Marketplace Listing Evaluator

An AI tool that helps a guitar shop decide what to buy. Paste in a Facebook Marketplace or Craigslist listing, and it identifies the item, estimates what it's worth, and lists what to check and what sellers commonly misrepresent, before anyone drives across town.

Listings evaluated, Mar–Jun 2026
~400
Client
A Front Range music retailer that buys used guitars and gear from private sellers.
Status
In use Mar–Jun 2026
/ The Challenge

Where the hours were going.

A used-gear shop makes its margin when it buys. Much of its stock comes from private sellers on Facebook Marketplace and Craigslist, where listings are short, photos are poor, and the asking price says little about real value. Many listings are misidentified, overpriced, or quietly hiding a problem.

Checking each one meant researching the model, guessing the year from blurry photos, looking up recent sales, and remembering what tends to go wrong with that model, often for dozens of listings a week. Most weren't worth pursuing, but finding the few that were took hours.

/ What We Built

The AI-enhanced workflow.

We built a listing evaluator into the shop's admin system. Staff paste in one or more listing links. The tool collects each listing's title, description, price, location, and photos automatically, then AI evaluates it.

Each evaluation identifies the item: category, brand, model, finish, likely year, and condition, plus a serial decode if a serial is visible. Where something is a guess, it says so. Years come as a tight range when exact dating isn't possible, and inferred brands or models are marked "not definitive".

It then values the item as low, typical, and high private-party prices, with notes on what a pawn shop would pay and what selling online would cost in fees and risk. The asking price is shown for context but deliberately left out of the valuation, so a hopeful seller can't anchor the estimate.

Finally, it lists what matters before buying: known weak points and typical repairs for that model, what to check in person, what sellers commonly misrepresent, the original specs for pickups and tuners, and common modifications. Results land in a scored list the shop can sort, review, and archive.

/ Capabilities

What it does.

F-01

Link in, evaluation out

Paste Marketplace or Craigslist links; the listing details and photos are collected automatically.

F-02

Honest identification

Brand, model, year, and condition, with uncertain answers clearly marked instead of presented as fact.

F-03

Value without anchoring

Low, typical, and high private-party values, worked out without looking at the seller's asking price.

F-04

What to check

Model-specific weak points, repair needs, and common misrepresentations, before anyone goes to see it.

/ How We Built It

From friction to system.

  1. Step 01

    Watch how buying works

    We followed how the shop found, researched, and judged listings, and where the hours went.

  2. Step 02

    Automate the collection

    Listing details and photos are gathered from the link, with no copying and pasting.

  3. Step 03

    Define a good evaluation

    The shop's buying knowledge became a consistent set of fields the AI fills in every time.

  4. Step 04

    Make it reviewable

    A scored results list with full detail pages, so staff can triage quickly.

/ Outcomes

What changed.

  • About 400 listings evaluated in its first three months of use
  • Research done before anyone spends time on a listing
  • The same identification and checklist on every listing, whoever is buying
  • Misidentified and overpriced listings filtered out early
/ Questions

Common questions.

Does the tool decide what to buy?
No. It does the research and flags the risks; the shop's buyer makes the call and still inspects the item in person.
Why ignore the asking price?
Because sellers often price on hope. Valuing the item first, then comparing it with the asking price, shows quickly whether a listing is a deal.
Can this work for other kinds of resale?
Yes. Any business that buys used items from private sellers, such as furniture, tools, electronics, or collectibles, faces the same research problem.