get_crypto_prices

Instructions

Implementation Reference

• src/index.ts:246-258 (registration)

  Tool registered in the TOOLS array with name 'get_crypto_prices', description, and an empty inputSchema (no parameters required).

  const TOOLS = [
    {
      name: 'get_crypto_prices',
      description:
        'Get live cryptocurrency prices and top 24h movers. Returns BTC, ETH, SOL prices plus top gainers/losers. ' +
        'Costs 0.001 USDC per call (x402 micropayment on Base). ' +
        'Data sourced live from CoinGecko.',
      inputSchema: {
        type: 'object',
        properties: {},
        required: [],
      },
    },

• src/index.ts:446-448 (handler)

  Handler case in CallToolRequestSchema: calls callApi('/api/price-feed') which fetches live crypto prices via the x402 payment API.

  case 'get_crypto_prices':
    result = await callApi('/api/price-feed');
    break;

• src/index.ts:114-180 (helper)

  The callApi helper function handles all API requests, including x402 payment negotiation (auto-pay via wallet or manual 402 response) and 30-second timeout.

  async function callApi(
    endpoint: string,
    params: Record<string, string | number | undefined> = {}
  ): Promise<ApiResponse> {
    const url = new URL(`${API_BASE_URL}${endpoint}`);
    for (const [key, value] of Object.entries(params)) {
      if (value !== undefined && value !== '') {
        url.searchParams.set(key, String(value));
      }
    }
  
    const fetchFn = await getX402Fetch();
  
    let response: Response;
    const controller = new AbortController();
    const fetchTimeout = setTimeout(() => controller.abort(), 30_000);
    try {
      response = await fetchFn(url.toString(), {
        headers: {
          'Accept': 'application/json',
          'User-Agent': `x402-api-mcp/${SERVER_VERSION}`,
        },
        signal: controller.signal,
      });
    } catch (err) {
      const isTimeout = err instanceof Error && err.name === 'AbortError';
      throw new McpError(
        ErrorCode.InternalError,
        isTimeout
          ? `Request to ${endpoint} timed out after 30 seconds`
          : `Network error calling ${endpoint}: ${err instanceof Error ? err.message : String(err)}`
      );
    } finally {
      clearTimeout(fetchTimeout);
    }
  
    if (response.status === 402) {
      // Clone before reading so we can fall back to text() if JSON parsing fails.
      // Without the clone, calling response.json() consumes the body; a subsequent
      // response.text() call then throws "body already used".
      const cloned = response.clone();
      let paymentDetails: unknown;
      try {
        paymentDetails = await response.json();
      } catch {
        paymentDetails = await cloned.text();
      }
      return { status: 402, data: null, paymentRequired: true, paymentDetails };
    }
  
    if (!response.ok) {
      const errorText = await response.text();
      if (response.status === 400 || response.status === 422) {
        throw new McpError(
          ErrorCode.InvalidParams,
          `Invalid request to ${endpoint}: ${errorText}`
        );
      }
      throw new McpError(
        ErrorCode.InternalError,
        `API error ${response.status} from ${endpoint}: ${errorText}`
      );
    }
  
    const data = await response.json();
    return { status: response.status, data };
  }

• src/index.ts:107-108 (helper)

  The ApiResponse interface used by the handler to structure the return value.

  interface ApiResponse {
    status: number;