{description: 'The `$hddt-cgm-summary` operation is defined on the *Observation* resource type.  \nIt allows clients to request CGM summary data filtered by effective period, and optionally include related device context (Device, DeviceMetric).  \n\n**Use cases supported by this operation include:**  \n- Retrieving CGM summary statistics (mean glucose, time-in-range, GMI, etc.) for a patient over a specified interval  \n\n**Input Parameters:**  \n- `effectivePeriodStart` *(dateTime, optional)*: Lower bound of the observation effective period.  \n- `effectivePeriodEnd` *(dateTime, optional)*: Upper bound of the observation effective period.  \n- `related` *(boolean, optional)*: If true, the response bundle also contains related Device and DeviceMetric resources.  \n\n**Output Parameter:**  \n- `result` *(Reference, required)*: A Bundle conforming to profile `HddtCgmSummary` profile containing all matching CGM Observations and, if requested, their related devices.  \n\n**Error handling (OperationOutcome):**  \n- `MSG_PARAM_UNKNOWN`: Returned when an unsupported input parameter is used.  \n- `MSG_PARAM_INVALID`: Returned when a parameter value is invalid (e.g., bad date format).  \n- `MSG_NO_MATCH`: Returned when no matching observations are found. \n- `MSG_BAD_SYNTAX`: Returned when the request is malformed.  \n', package_name: de.gematik.hddt, name: HddtCgmSummaryOperation, type: 'true', package_version: 1.0.0-rc, class: operation, kind: operation, url: 'https://gematik.de/fhir/hddt/OperationDefinition/hddt-cgm-summary-operation', version: 1.0.0-rc}