Turn Claude or ChatGPT into an AI thrifting assistant

Thrifting online is a grind: four marketplaces with four different search UIs, loose keyword matching, and no good way to compare a Facebook Marketplace find against what the same item goes for on eBay. An AI assistant with marketplace access collapses all of that into a conversation.

Secondhand MCP is a connector that gives Claude and ChatGPT real search access to Facebook Marketplace, eBay, Depop, and Poshmark — with actual filters (price, condition, size, color, category, brand) and full listing details including photos. Here is what that unlocks.

1. Search by describing, not by keyword-guessing

"Find a solid-wood mid-century dresser under $250 near Oakland, no veneer damage" is a terrible marketplace query and a perfect AI request. The assistant translates it into filtered searches, reads the descriptions, looks at photos, and returns the listings that actually match — not everything containing the word "dresser."

2. Price-check before you buy

Found something local? Ask the AI to check what the same item lists for on eBay before you drive across town. Because eBay results come from the official API with structured prices and conditions, "is $900 fair for this Peloton?" gets a real answer with comparables, not a vibe.

3. Judge condition from photos, in the chat

Listing details include every photo. Ask the assistant to pull them inline and point out wear, damage, or missing parts — before you message a seller or place a bid.

4. Hunt fashion with real filters

On Depop and Poshmark, size, color, brand, department, and condition (including new-with-tags) are true server-side filters. "NWT Lululemon Align leggings, size 6, under $60, both marketplaces" is one sentence — the AI runs both searches and merges what it finds.

5. Research like a reseller

For sourcing, Pro+'s "search all at once" runs one query across all four marketplaces simultaneously — the fastest way to spot an item priced low on one marketplace that sells high on another. See searching all marketplaces at once for that workflow.

Prompts to steal

• Find me a Herman Miller Aeron under $350 within 25 miles of Denver, and check what refurbished ones go for on eBay
• Search Depop and Poshmark for vintage Levi's trucker jackets, size M, under $80 — show photos of the three best
• I'm furnishing an apartment: find a couch, coffee table, and floor lamp on Facebook Marketplace in Austin, $600 total budget
• What's the going rate for a used Nintendo Switch OLED? Check eBay and tell me what a fair local offer would be

Getting set up

Setup is one connector added to Claude or ChatGPT — about 30 seconds, free tier included, no credit card. Prefer self-hosting? The open-source version runs locally.