API

ShuffleReady's public API says whether a Magic: The Gathering deck is legal in a format and why not, today or on any past date, using each format's dated rules and ban lists (Commander back to 2002). It's free, with no key: up to 30 requests a minute per IP, and 10 for decks given as a link.

• OpenAPI description of every endpoint and field
• llms.txt , the same for language models

Use with Claude or ChatGPT

The MCP server lets a chatbot or agent check decks for you: "is this deck legal in Commander?", "what was banned in EDH in 2007?". Add its url as a custom connector (in Claude: Settings, Connectors, Add custom connector; in ChatGPT: a connector in developer mode). It needs no sign in.

https://shuffleready.com/mcp

Its tools only read:

• check_deck_legality : Is a deck legal in up to 5 formats, today or on a date?
• list_formats : The format slugs.
• format_rules_on_date : A format's checks and its banned, restricted and banned as commander cards on a date.
• card_legality : Is a card legal in each official format, and why not?

Check a deck

POST /api/v1/legality with a JSON body. Is this deck legal in Commander today?

curl -s https://shuffleready.com/api/v1/legality \
  -H 'content-type: application/json' \
  -d '{"deck":"Commander\n1 Kenrith, the Returned King\nDeck\n1 Sol Ring\n1 Mana Crypt","formats":["commander"]}'

GET /api/v1/legality takes the same as query parameters, for short decks:

curl -s 'https://shuffleready.com/api/v1/legality?deck=4%20Lightning%20Bolt%0A4%20Brainstorm&format=vintage&format=legacy'

Request

Response

{
  "asOf": "2007-12-31",
  "allowNewCards": false,
  "deck": { "cards": 2, "unresolved": [] },
  "results": [
    {
      "format": { "id": 32, "slug": "commander", "name": "Commander" },
      "formatVersion": { "id": 9900, "effectiveFrom": "2006-02-01" },
      "legal": false,
      "status": "FAILED_CHECKS",
      "tier": null,
      "errors": [
        {
          "check": "NOT_YET_PRINTED",
          "description": "Cards printed after 2007-12-31",
          "cards": [
            {
              "name": "Jeweled Lotus",
              "reason": "Not yet printed on 2007-12-31 (first printed 2020-11-20)"
            }
          ],
          "messages": []
        }
      ]
    }
  ],
  "links": { "checkOnSite": "https://shuffleready.com/format/1/32/commander" }
}

Errors are { "error": { "code", "message" } } :

• BAD_REQUEST (400) : The input, and what's wrong.
• UNKNOWN_FORMAT (404) : A format no slug or id names, with the slugs.
• DECK_URL_FAILED (400) : The deck's link didn't load: send its text instead.
• RATE_LIMITED (429) : Over the limit: try again in a minute.
• BUSY, TIMEOUT (503) : Too many checks at once, or one took too long.

On a past date

With asOf , the format's rules and ban lists in effect on that date apply, and cards printed after it fail as not yet printed. Was this deck legal in EDH at the end of 2007?

curl -s https://shuffleready.com/api/v1/legality \
  -H 'content-type: application/json' \
  -d '{"deck":"1 Sol Ring\n1 Jeweled Lotus","formats":["edh"],"asOf":"2007"}'

Add allowNewCards to play by 2007's ban list with today's cards:

curl -s https://shuffleready.com/api/v1/legality \
  -H 'content-type: application/json' \
  -d '{"deck":"1 Sol Ring\n1 Jeweled Lotus","formats":["edh"],"asOf":"2007","allowNewCards":true}'

Formats

Name a format by its slug, or one of its other names. GET /api/v1/formats lists them:

Any other public format on ShuffleReady can be named by its id. Questions or a format missing? See the contact page .