technicalIndicators_dema
Calculate the Double Exponential Moving Average (DEMA) for stock analysis. Analyze price trends using symbol, interval, time period, and series type parameters to assess market movements effectively.
Instructions
Double Exponential Moving Average (DEMA)
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| datatype | No | Data format for the response. | json |
| interval | Yes | Time interval (e.g., "daily", "60min", "weekly"). Check Alpha Vantage docs for valid intervals per indicator. | |
| month | No | Specific month for intraday intervals (YYYY-MM format). | |
| series_type | Yes | The desired price type. | |
| symbol | Yes | The stock symbol (e.g., "IBM"). | |
| time_period | Yes | Number of data points used to calculate the indicator. |
Input Schema (JSON Schema)
{
"additionalProperties": false,
"description": "Parameters for time series based technical indicators.",
"properties": {
"datatype": {
"default": "json",
"description": "Data format for the response.",
"enum": [
"json",
"csv"
],
"type": "string"
},
"interval": {
"description": "Time interval (e.g., \"daily\", \"60min\", \"weekly\"). Check Alpha Vantage docs for valid intervals per indicator.",
"type": "string"
},
"month": {
"description": "Specific month for intraday intervals (YYYY-MM format).",
"type": "string"
},
"series_type": {
"description": "The desired price type.",
"enum": [
"close",
"open",
"high",
"low"
],
"type": "string"
},
"symbol": {
"description": "The stock symbol (e.g., \"IBM\").",
"type": "string"
},
"time_period": {
"description": "Number of data points used to calculate the indicator.",
"type": "string"
}
},
"required": [
"symbol",
"interval",
"time_period",
"series_type"
],
"type": "object"
}
Implementation Reference
- src/index.ts:38-115 (handler)Core handler function that executes all Avantage technical indicator tools, including 'technicalIndicators_dema'. Manages API key resolution, AVantage instance via resourceManager, library method invocation (e.g., av.technicalIndicators.dema(params)), error handling, and JSON response formatting.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}` ); } }
- src/schemas.ts:204-215 (schema)Zod schema definition for parameters of 'technicalIndicators_dema' tool: requires symbol, interval, time_period, series_type (close/open/high/low), with optional datatype and month.export const TechnicalIndicatorsCommonIndicatorParamsSchema = z.object({ symbol: z.string().describe('The stock symbol (e.g., "IBM").'), interval: z.string().describe('Time interval (e.g., "daily", "60min", "weekly"). Check Alpha Vantage docs for valid intervals per indicator.'), datatype: DatatypeSchema.default('json').optional(), month: z.string().optional().describe('Specific month for intraday intervals (YYYY-MM format).'), }).describe('Common parameters for many technical indicators.') // Schema for indicators requiring time_period and series_type export const TechnicalIndicatorsTimeSeriesIndicatorParamsSchema = TechnicalIndicatorsCommonIndicatorParamsSchema.extend({ time_period: z.string().describe('Number of data points used to calculate the indicator.'), // Using string as AV API expects string series_type: SeriesTypeSchema, }).describe('Parameters for time series based technical indicators.')
- src/index.ts:1028-1042 (registration)FastMCP server.addTool registration for 'technicalIndicators_dema', specifying schema and delegating execution to generic handler calling AVantage library's dema method.server.addTool({ name: "technicalIndicators_dema", description: "Double Exponential Moving Average (DEMA)", parameters: schemas.TechnicalIndicatorsTimeSeriesIndicatorParamsSchema, execute: ( args, context // Let type be inferred ) => executeAvantageTool( "technicalIndicators_dema", args, context, (av, params) => av.technicalIndicators.dema(params) ), });