Scryfall MCP Server

const DEFAULT_BASE_URL = "https://backend.commanderspellbook.com"; function buildUrl(path: string, params?: Record<string, unknown>, base = DEFAULT_BASE_URL) { const url = new URL(path, base); if (params) { for (const [k, v] of Object.entries(params)) { if (v === undefined || v === null) continue; url.searchParams.set(k, String(v)); } } return url; } // Polite rate limiter (reusing pattern from Scryfall client) const intervalMs = Number(process.env.CSB_INTERVAL_MS || 100); let lastStart = 0; let queue: Promise<void> = Promise.resolve(); function sleep(ms: number) { return new Promise((r) => setTimeout(r, ms)); } async function acquireSlot(): Promise<void> { const prev = queue; let release: () => void; const next = new Promise<void>((r) => (release = r)); queue = next; await prev; const now = Date.now(); const wait = Math.max(0, lastStart + intervalMs - now); if (wait > 0) await sleep(wait); lastStart = Date.now(); release!(); } async function getJson(path: string, params?: Record<string, unknown>) { const base = process.env.CSB_BASE_URL || DEFAULT_BASE_URL; const url = buildUrl(path, params, base); const maxRetries = Number(process.env.CSB_MAX_RETRIES || 3); const retryBaseMs = Number(process.env.CSB_RETRY_BASE_MS || 250); for (let attempt = 0; attempt <= maxRetries; attempt++) { await acquireSlot(); const res = await fetch(url, { headers: { "User-Agent": "scryfall-mcp/0.1 (https://github.com/latte-chan/scryfall-connector)" } }); if (res.status === 429) { const retryAfter = Number(res.headers.get("Retry-After") || 0); const backoff = retryAfter > 0 ? retryAfter * 1000 : retryBaseMs * Math.pow(2, attempt); if (attempt < maxRetries) { await sleep(backoff); continue; } } if (!res.ok) { const text = await res.text().catch(() => ""); throw new Error(`CSB request failed: ${res.status} ${res.statusText} - ${text}`); } return res.json() as Promise<unknown>; } throw new Error("CSB request failed after retries"); } async function postText(path: string, body: string) { const base = process.env.CSB_BASE_URL || DEFAULT_BASE_URL; const url = new URL(path, base); const maxRetries = Number(process.env.CSB_MAX_RETRIES || 3); const retryBaseMs = Number(process.env.CSB_RETRY_BASE_MS || 250); for (let attempt = 0; attempt <= maxRetries; attempt++) { await acquireSlot(); const res = await fetch(url, { method: "POST", headers: { "Content-Type": "text/plain", "User-Agent": "scryfall-mcp/0.1 (commanderspellbook client)" }, body }); if (res.status === 429) { const retryAfter = Number(res.headers.get("Retry-After") || 0); const backoff = retryAfter > 0 ? retryAfter * 1000 : retryBaseMs * Math.pow(2, attempt); if (attempt < maxRetries) { await sleep(backoff); continue; } } if (!res.ok) { const text = await res.text().catch(() => ""); throw new Error(`CSB request failed: ${res.status} ${res.statusText} - ${text}`); } return res.json() as Promise<unknown>; } throw new Error("CSB request failed after retries"); } export const CSB = { parseCardListFromText: (text: string) => postText("/card-list-from-text", text), findMyCombos: (ids: number[], limit?: number, offset?: number) => getJson("/find-my-combos", { ids: ids.join(","), limit, offset }), variants: (opts: { uses?: number; produces?: number; of?: number; limit?: number; offset?: number }) => getJson("/variants", opts), getCard: (id: number) => getJson(`/cards/${id}`), cards: (opts?: { limit?: number; offset?: number; search?: string; name?: string; oracleId?: string }) => getJson("/cards", opts || {}) }; export type CSBAPI = typeof CSB;