FitBit MCP

Implementation Reference

• src/server.ts:110-146 (handler)

  Handler function that fetches daily activities from Fitbit API using the provided date (defaults to today), formats and returns the activities and summary data, or an error response.

  async ({ date }) => {
    try {
      const formattedDate = formatDate(date);
      // Use the correct endpoint format without period
      const endpoint = `/user/-/activities/date/${formattedDate}.json`;
  
      const data = await makeApiRequest(endpoint);
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(
              {
                date: formattedDate,
                activities: data.activities || [],
                summary: data.summary || {},
              },
              null,
              2
            ),
          },
        ],
      };
    } catch (error) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${
              error instanceof Error ? error.message : String(error)
            }`,
          },
        ],
        isError: true,
      };
    }
  }

• src/server.ts:104-109 (schema)

  Input schema defining optional 'date' parameter using Zod for validation.

  {
    date: z
      .string()
      .optional()
      .describe("Date in YYYY-MM-DD format. If not specified, will use today."),
  },

• src/server.ts:102-147 (registration)

  Registration of the 'getActivities' tool on the MCP server, including schema and handler.

  server.tool(
    "getActivities",
    {
      date: z
        .string()
        .optional()
        .describe("Date in YYYY-MM-DD format. If not specified, will use today."),
    },
    async ({ date }) => {
      try {
        const formattedDate = formatDate(date);
        // Use the correct endpoint format without period
        const endpoint = `/user/-/activities/date/${formattedDate}.json`;
  
        const data = await makeApiRequest(endpoint);
        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(
                {
                  date: formattedDate,
                  activities: data.activities || [],
                  summary: data.summary || {},
                },
                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.

  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 HTTP requests to the Fitbit API and handle responses/errors.

  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;
    }