get_weight
Retrieve weight data from Fitbit for a specified time period. Use this tool to access historical weight entries by providing a period parameter like '7d' or '1y'.
Instructions
Get the raw JSON response for weight entries from Fitbit for a specified period ending today. Requires a 'period' parameter such as '1d', '7d', '30d', '3m', '6m', '1y'
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| period | Yes | The time period for which to retrieve data |
Implementation Reference
- src/weight.ts:39-52 (handler)The handler function that executes the get_weight tool logic: constructs the Fitbit API endpoint for body weight data over a given period and invokes handleFitbitApiCall to fetch, extract, and format the response.
handler: async ({ period }: WeightParams) => { const endpoint = `/body/weight/date/today/${period}.json`; return handleFitbitApiCall<WeightTimeSeriesResponse, WeightParams>( endpoint, { period }, getAccessTokenFn, { successDataExtractor: (data) => data['body-weight'] || [], noDataMessage: `the period '${period}'`, errorContext: `period '${period}'` } ); } - src/weight.ts:33-53 (registration)Registration of the get_weight tool via registerTool, specifying name, description, input schema (period parameter), and handler function.
registerTool(server, { name: 'get_weight', description: "Get the raw JSON response for weight entries from Fitbit for a specified period ending today. Requires a 'period' parameter such as '1d', '7d', '30d', '3m', '6m', '1y'", parametersSchema: { period: CommonSchemas.period, }, handler: async ({ period }: WeightParams) => { const endpoint = `/body/weight/date/today/${period}.json`; return handleFitbitApiCall<WeightTimeSeriesResponse, WeightParams>( endpoint, { period }, getAccessTokenFn, { successDataExtractor: (data) => data['body-weight'] || [], noDataMessage: `the period '${period}'`, errorContext: `period '${period}'` } ); } }); - src/index.ts:77-77 (registration)Top-level call to registerWeightTool, which sets up the get_weight tool on the MCP server instance.
registerWeightTool(server, getAccessToken); - src/weight.ts:10-19 (schema)TypeScript interfaces defining the structure of Fitbit weight time series data used in the tool's handler.
interface WeightTimeSeriesEntry { dateTime: string; // Date (and potentially time) of the entry value: string; // Weight value as a string } // Represents the structure of the response from the Fitbit Time Series API for weight interface WeightTimeSeriesResponse { 'body-weight': WeightTimeSeriesEntry[]; // Array of weight entries } - src/utils.ts:183-222 (helper)Shared helper function handleFitbitApiCall used by the get_weight handler to perform the API request, handle authentication, errors, no-data cases, and format the MCP tool response.
export async function handleFitbitApiCall<TResponse, TParams>( endpoint: string, params: TParams, getAccessTokenFn: () => Promise<string | null>, options: { apiBase?: string; successDataExtractor?: (data: TResponse) => unknown[] | null; noDataMessage?: string; errorContext?: string; } = {} ): Promise<ToolResponseStructure> { const { apiBase = FITBIT_API_VERSIONS.V1, successDataExtractor, noDataMessage, errorContext = JSON.stringify(params) } = options; const responseData = await makeFitbitRequest<TResponse>( endpoint, getAccessTokenFn, apiBase ); if (!responseData) { return createErrorResponse( `${ERROR_MESSAGES.API_REQUEST_FAILED} for ${errorContext}. ${ERROR_MESSAGES.CHECK_TOKEN_PERMISSIONS}.` ); } // Check for empty data if extractor provided if (successDataExtractor) { const extractedData = successDataExtractor(responseData); if (!extractedData || extractedData.length === 0) { return createNoDataResponse(noDataMessage || errorContext); } } return createSuccessResponse(responseData); }