Midpoint MCP server: trading card prices and grading ROI for ChatGPT, Claude and any AI agent

What you can ask

Plain questions work. The assistant picks the tool, finds the card, and answers with prices, dates and a link. Some of the things collectors ask every day:

What every answer contains

• Raw (ungraded) prices by condition: Near Mint, Lightly Played, Moderately Played, Heavily Played and Damaged where the market reports them.
• The graded ladder: PSA 10 down through the grades, plus CGC, BGS, SGC and TAG 10s, so you can see which company pays most for the same card.
• Grading economics: PSA 9 and PSA 10 premium over raw, net profit after $25, $50 and $150 fee tiers, expected value at 25, 50 and 75 percent gem rates, the break-even gem rate, and a plain verdict, the same maths as our worth-grading pages.
• Price history: dated market values for the raw series or any PSA grade over 7 to 180 days.
• Market movement: biggest 30-day gainers and drops per game, and liquid movers filtered to cards with real sales volume. See also Trends.
• Sets and checklists: every expansion and priced checklist, sorted by value or card number, with links to our set pages.
• The capture date and a link on every result, so the assistant can cite the card page rather than paraphrase it.

Trading card games

English-language cards priced raw and graded, from vintage Base Set and Alpha through this month's expansions. Example questions per game:

Sports cards

Rookies, refractors, autographs and vintage across every major sport, with player pages that group a player's cards by year. Search by player, year and brand the way you would say it out loud: “2003 Topps Chrome LeBron”, “Gretzky rookie”, “Ohtani Bowman Chrome”.

Entertainment and other sets

Tools

All tools are read-only and idempotent. Start with search_cards to get a card id (the same id as our URLs: swsh7-215, pricecharting-1821843), then pass it to the others.

Game keys: pokemon · magicthegathering · yugioh · onepiece · lorcana · riftbound · gundam · baseball · basketball · football · hockey · soccer · wrestling · ufc · racing · tennis · golf · boxing · marvel · starwars · gpk · dragonball · digimon · entertainment · othertcg

Connect

claude plugin marketplace add kolourr/midpoint-claude-plugin
claude plugin install midpoint-card-prices@midpoint

claude mcp add --transport http midpoint https://mcp.cardcenteringtool.com/mcp

{
  "mcpServers": {
    "midpoint": {
      "url": "https://mcp.cardcenteringtool.com/mcp"
    }
  }
}

curl -X POST https://mcp.cardcenteringtool.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"search_cards","arguments":{"query":"Umbreon VMAX Evolving Skies","game":"pokemon"}}}'

What it does not do

• Grade or measure a card from a photo. Centering measurement and the AI grade estimate are in the Midpoint app and the web scanner.
• Buy, sell or list cards.
• Forecast prices.
• Access any account or collection data.

Frequently asked questions