forex_exchangeRates
Retrieve real-time foreign exchange rates for specified currency pairs using the MCP Avantage server. Input source and target currency symbols to get accurate conversion data.
Instructions
Fetches the realtime exchange rate for a currency pair (e.g., EUR to USD).
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| from_currency | Yes | The currency symbol to convert from (e.g., "EUR"). | |
| to_currency | Yes | The currency symbol to convert to (e.g., "USD"). |
Input Schema (JSON Schema)
{
"additionalProperties": false,
"description": "Parameters for fetching Forex exchange rates.",
"properties": {
"from_currency": {
"description": "The currency symbol to convert from (e.g., \"EUR\").",
"type": "string"
},
"to_currency": {
"description": "The currency symbol to convert to (e.g., \"USD\").",
"type": "string"
}
},
"required": [
"from_currency",
"to_currency"
],
"type": "object"
}
Implementation Reference
- src/index.ts:714-720 (handler)The execute handler for the 'forex_exchangeRates' tool. It invokes the generic executeAvantageTool helper, passing a specific callback that calls the AVantage library's forex.exchangeRates method with the from_currency and to_currency parameters.execute: ( args, context // Let type be inferred ) => executeAvantageTool("forex_exchangeRates", args, context, (av, params) => av.forex.exchangeRates(params.from_currency, params.to_currency) ),
- src/schemas.ts:145-148 (schema)Zod schema defining the input parameters for the tool: from_currency and to_currency strings.export const ForexExchangeRateParamsSchema = z.object({ from_currency: z.string().describe('The currency symbol to convert from (e.g., "EUR").'), to_currency: z.string().describe('The currency symbol to convert to (e.g., "USD").'), }).describe('Parameters for fetching Forex exchange rates.')
- src/index.ts:709-721 (registration)Registration of the 'forex_exchangeRates' MCP tool on the FastMCP server instance, including name, description, input schema reference, and handler.server.addTool({ name: "forex_exchangeRates", description: "Fetches the realtime exchange rate for a currency pair (e.g., EUR to USD).", parameters: schemas.ForexExchangeRateParamsSchema, execute: ( args, context // Let type be inferred ) => executeAvantageTool("forex_exchangeRates", args, context, (av, params) => av.forex.exchangeRates(params.from_currency, params.to_currency) ), });
- src/index.ts:38-115 (helper)Generic helper function used by all Avantage tools, including forex_exchangeRates. Manages authentication, AVantage instance via resourceManager, executes the provided library method, handles errors, and returns JSON stringified data.async function executeAvantageTool<TArgs, TResult>( toolName: string, args: TArgs, context: Context<Record<string, unknown> | undefined>, // Use the imported Context type directly avantageMethod: ( av: AVantage, args: TArgs ) => Promise<{ error?: boolean; reason?: string; data?: TResult }> ): Promise<string> { logger.info(`Executing '${toolName}' tool for request ID: ${context}`); logger.debug(`Args for ${toolName}: ${JSON.stringify(args)}`); // --- Authentication & Resource Management --- // Access extraArgs safely - it might be null or undefined const extraArgsApiKey = context.extraArgs?.apiKey as string | undefined; const apiKey = extraArgsApiKey || config.apiKey; if (!apiKey) { logger.error(`'${toolName}' failed: Alpha Vantage API key missing.`); throw new UserError(apiKeyErrorMessage); } logger.debug( `Using AV API key (source: ${extraArgsApiKey ? "extraArgs" : "environment"}) for ${toolName}` ); try { // Get or create AVantage instance managed by ResourceManager const av = await resourceManager.getResource<AVantage>( apiKey, // Cache key is the resolved API key "avantage_client", // Type identifier for logging async (key) => { // Factory Function logger.info( `Creating new AVantage instance for key ending ...${key.slice(-4)}` ); // AVantage library reads AV_PREMIUM from process.env internally return new AVantage(key); }, async (avInstance) => { // Cleanup Function (no-op needed for AVantage) logger.debug(`Destroying AVantage instance (no-op)`); } ); // --- Library Call --- const result = await avantageMethod(av, args); // --- Response Handling --- if (result.error) { logger.warn( `'${toolName}' failed. Reason from avantage: ${result.reason}` ); throw new UserError(result.reason || `Tool '${toolName}' failed.`); } if (result.data === undefined || result.data === null) { logger.warn(`'${toolName}' completed successfully but returned no data.`); return "null"; // Return string "null" for empty data } logger.info(`'${toolName}' completed successfully.`); // Stringify the data part of the response return JSON.stringify(result.data); } catch (error: any) { logger.error( `Error during execution of '${toolName}': ${error.message}`, error ); // If it's already a UserError, rethrow it if (error instanceof UserError) { throw error; } // Otherwise, wrap it in a UserError throw new UserError( `An unexpected error occurred while executing tool '${toolName}': ${error.message}` ); } }