getBodyMeasurements

Retrieve body measurements like weight and body fat from Fitbit data for a specific date or time period to track health progress.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`date`	No	Date in YYYY-MM-DD format. If not specified, will use today.
`period`	No	Period for body data: 1d, 7d, 30d, 1w, 1m

Implementation Reference

src/server.ts:324-376 (handler)

Handler function that fetches weight and body fat measurements from the Fitbit API for the specified date and optional period, returning JSON-formatted data or an error.

async ({ date, period }) => {
  try {
    const formattedDate = formatDate(date);
    let endpoint = "";

    if (period) {
      endpoint = `/user/-/body/log/weight/date/${formattedDate}/${period}.json`;
    } else {
      endpoint = `/user/-/body/log/weight/date/${formattedDate}.json`;
    }

    const weightData = await makeApiRequest(endpoint);

    // Also get body fat data
    let fatEndpoint = "";
    if (period) {
      fatEndpoint = `/user/-/body/log/fat/date/${formattedDate}/${period}.json`;
    } else {
      fatEndpoint = `/user/-/body/log/fat/date/${formattedDate}.json`;
    }

    const fatData = await makeApiRequest(fatEndpoint);

    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(
            {
              date: formattedDate,
              weight: weightData.weight || [],
              fat: fatData.fat || [],
            },
            null,
            2
          ),
        },
      ],
    };
  } catch (error) {
    return {
      content: [
        {
          type: "text",
          text: `Error: ${
            error instanceof Error ? error.message : String(error)
          }`,
        },
      ],
      isError: true,
    };
  }
}

src/server.ts:314-323 (schema)

Zod input schema defining optional 'date' and 'period' parameters for the getBodyMeasurements tool.

{
  date: z
    .string()
    .optional()
    .describe("Date in YYYY-MM-DD format. If not specified, will use today."),
  period: z
    .string()
    .optional()
    .describe("Period for body data: 1d, 7d, 30d, 1w, 1m"),
},

src/server.ts:312-377 (registration)

Registration of the getBodyMeasurements tool on the MCP server, including name, input schema, and handler function.

server.tool(
  "getBodyMeasurements",
  {
    date: z
      .string()
      .optional()
      .describe("Date in YYYY-MM-DD format. If not specified, will use today."),
    period: z
      .string()
      .optional()
      .describe("Period for body data: 1d, 7d, 30d, 1w, 1m"),
  },
  async ({ date, period }) => {
    try {
      const formattedDate = formatDate(date);
      let endpoint = "";

      if (period) {
        endpoint = `/user/-/body/log/weight/date/${formattedDate}/${period}.json`;
      } else {
        endpoint = `/user/-/body/log/weight/date/${formattedDate}.json`;
      }

      const weightData = await makeApiRequest(endpoint);

      // Also get body fat data
      let fatEndpoint = "";
      if (period) {
        fatEndpoint = `/user/-/body/log/fat/date/${formattedDate}/${period}.json`;
      } else {
        fatEndpoint = `/user/-/body/log/fat/date/${formattedDate}.json`;
      }

      const fatData = await makeApiRequest(fatEndpoint);

      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(
              {
                date: formattedDate,
                weight: weightData.weight || [],
                fat: fatData.fat || [],
              },
              null,
              2
            ),
          },
        ],
      };
    } catch (error) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${
              error instanceof Error ? error.message : String(error)
            }`,
          },
        ],
        isError: true,
      };
    }
  }
);

src/server.ts:68-72 (helper)

Helper function to format or default the date to today in YYYY-MM-DD format, used by getBodyMeasurements.

function formatDate(date?: string): string {
  if (date) return date;
  const today = new Date();
  return today.toISOString().split("T")[0]; // YYYY-MM-DD
}

src/server.ts:44-64 (helper)

Helper function to make authenticated API requests to Fitbit endpoints, used by the getBodyMeasurements handler.

async function makeApiRequest(endpoint: string): Promise<any> {
  try {
    const url = `${baseUrl}${endpoint}`;
    const response = await fetch(url, {
      headers: {
        Authorization: `Bearer ${accessToken}`,
        Accept: "application/json",
      },
    });

    if (!response.ok) {
      throw new Error(
        `Fitbit API error: ${response.status} ${response.statusText}`
      );
    }

    return await response.json();
  } catch (error) {
    console.error(`Error making request to ${endpoint}:`, error);
    throw error;
  }

FitBit MCP