capture-fixture

name	capture-fixture
description	Capture a live API response as a JSON test fixture for a given service and endpoint
disable-model-invocation	true

Capture Fixture

Capture a real API response and save it as a JSON fixture for TDD testing.

Usage

/capture-fixture <service> <description>

Examples:

• /capture-fixture scryfall card lookup for Muldrotha
• /capture-fixture spellbook combos for Muldrotha
• /capture-fixture 17lands card ratings for LRW PremierDraft
• /capture-fixture edhrec commander page for Muldrotha

Workflow

1. Identify the endpoint from docs/SERVICE_CONTRACTS.md based on the service and description.

2. Make the request using curl or python -c with httpx. Include required headers:

   • Scryfall: User-Agent: mtg-mcp-server/<version> and Accept: application/json
   • All others: Accept: application/json

3. Save the response to tests/fixtures/<service>/:

   • Use a descriptive snake_case filename (e.g., card_muldrotha.json, search_sultai_commander.json, card_not_found.json)
   • Pretty-print with jq . or python -m json.tool
   • Create the directory if it doesn't exist

4. Capture error responses too — 404s, rate limits, etc. are valuable fixtures.

5. Show the user:

   • The full URL hit
   • The saved file path
   • A brief summary of the response shape (top-level keys, array lengths)

Service Endpoints Quick Reference

Service	Base URL	Key Endpoints
scryfall	https://api.scryfall.com	/cards/named?exact=, /cards/search?q=, /cards/{id}/rulings
spellbook	https://backend.commanderspellbook.com	/api/variants/?q=, /api/estimate-bracket/
17lands	https://www.17lands.com	/card_ratings/data?expansion=&format=
edhrec	https://json.edhrec.com	/pages/commanders/{slug}.json, /pages/cards/{slug}.json

Rules

• Never overwrite an existing fixture without asking first
• Always pretty-print JSON
• Respect rate limits — wait between requests if capturing multiple fixtures
• EDHREC slugs: lowercase, hyphens for spaces, strip commas/apostrophes