KH Merch Graph MCP server

KH Merch Graph

An MCP (Model Context Protocol) server that turns a Japanese secondhand-listing title for Kingdom Hearts merchandise (Mercari, Yahoo! Auctions, Suruga-ya, Mandarake, …) into: the likely official SKU, what the condition wording actually means, bootleg-caution flags, a price-to-MSRP ratio, and a landed-cost estimate to your country. Point any MCP-capable AI agent at it and hand it listing text — it does the rest.

Try it in your browser (no AI agent needed): https://merchgraph.app

Why this is different

primary source (an official product page, a maker's press release, etc.) — the source URL is attached to every entry and returned with every match, so you can check it yourself. Nothing is inferred by an LLM inside the server.

1. Verified catalog, not scraped or guessed. Every SKU in the catalog was checked by a human against a

guess as an answer. Low-confidence matches are returned separately as weak_matches, never mixed into candidates — an empty candidates array means "probably not in the catalog," not "best effort."

1. No confident guess, no candidate. When the match confidence is low, this server does not present a

listing text or URL you send it. You already have the listing open; you paste the text, it interprets it.

1. Bring Your Own Listing. This server never crawls or scrapes marketplaces itself, and never stores the

Supported IP

Kingdom Hearts only, for now. The catalog is hand-verified one SKU at a time, so it grows slowly on purpose. If you ask about another franchise, the server won't fabricate an answer — it notes the request (see Data sourcing & privacy) to help decide what to add next. Use report_correction or open a GitHub issue if you want to nominate a franchise or a specific missing SKU.

Usage examples

These are things you'd say to your AI agent once it's connected to this server (see Connect).

1. "Is this listing worth it?"

"I found this on Mercari for ¥8,000: 一番くじ KINGDOM HEARTS -25th Anniversary- A賞 ソラ スタチュー 開封済み.

What is it, and is that a fair price?"

The agent calls resolve_listing and gets back the matched SKU, the MSRP, the price ratio, the meaning of 「開封済み」("opened"), and a link to the primary source for that SKU.

2. "What Sora merch exists under ¥5,000?"

"Show me Kingdom Hearts Sora items under ¥5,000 that I could display."

The agent calls discover({ ip: "kingdom-hearts", character: "Sora", budget_jpy: 5000, purpose: "display" }) and gets a list of catalog SKUs matching those filters (this does not mean any of them are currently for sale anywhere — it's a catalog browse, not a marketplace search).

3. "What would it cost me, landed, in the US?"

"That listing is ¥8,000 plus it weighs about 400g. What's the total cost shipped to the US?"

The agent calls estimatelandedcost({ pricejpy: 8000, weightg: 400, dest_country: "US" }) and gets per-route estimates (proxy fee + shipping) with the cheapest option highlighted, plus when the rate table was last checked.

Connect

.../openapi.json (schema reference — the real transport is MCP's own tools/list/tools/call, this is a documentation aid for OpenAPI-only tooling)

• MCP endpoint (Streamable HTTP, JSON-RPC 2.0, no auth): https://mcp.merchgraph.app/mcp (the older https://kh-merch-graph.fandex.workers.dev/mcp keeps working)
• Health check: .../health
• For AI agents that discover servers by URL: .../llms.txt (plain-language entry point) and

Claude Desktop / Claude.ai

Add it as a custom connector using the MCP endpoint URL above. No API key or auth is required.

Any other MCP client

Point it at the /mcp endpoint with the Streamable HTTP transport. tools/list returns the live, authoritative schema for all five tools below.

Tools

Shortened. The full README is on GitHub.