Use PutAnomalyDetector with an Amazon SDK or CLI

    /// <summary>
    /// Add an anomaly detector for a single metric.
    /// </summary>
    /// <param name="anomalyDetector">A single metric anomaly detector.</param>
    /// <returns>True if successful.</returns>
    public async Task<bool> PutAnomalyDetector(SingleMetricAnomalyDetector anomalyDetector)
    {
        var putAlarmDetectorResult = await _amazonCloudWatch.PutAnomalyDetectorAsync(
            new PutAnomalyDetectorRequest()
            {
                SingleMetricAnomalyDetector = anomalyDetector
            });

        return putAlarmDetectorResult.HttpStatusCode == HttpStatusCode.OK;
    }

    public static void addAnomalyDetector(CloudWatchClient cw, String fileName) {
        try {
            // Read values from the JSON file.
            JsonParser parser = new JsonFactory().createParser(new File(fileName));
            com.fasterxml.jackson.databind.JsonNode rootNode = new ObjectMapper().readTree(parser);
            String customMetricNamespace = rootNode.findValue("customMetricNamespace").asText();
            String customMetricName = rootNode.findValue("customMetricName").asText();

            SingleMetricAnomalyDetector singleMetricAnomalyDetector = SingleMetricAnomalyDetector.builder()
                    .metricName(customMetricName)
                    .namespace(customMetricNamespace)
                    .stat("Maximum")
                    .build();

            PutAnomalyDetectorRequest anomalyDetectorRequest = PutAnomalyDetectorRequest.builder()
                    .singleMetricAnomalyDetector(singleMetricAnomalyDetector)
                    .build();

            cw.putAnomalyDetector(anomalyDetectorRequest);
            System.out.println("Added anomaly detector for metric " + customMetricName + ".");

        } catch (CloudWatchException | IOException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

suspend fun addAnomalyDetector(fileName: String?) {
    // Read values from the JSON file.
    val parser = JsonFactory().createParser(File(fileName))
    val rootNode = ObjectMapper().readTree<JsonNode>(parser)
    val customMetricNamespace = rootNode.findValue("customMetricNamespace").asText()
    val customMetricName = rootNode.findValue("customMetricName").asText()

    val singleMetricAnomalyDetectorVal =
        SingleMetricAnomalyDetector {
            metricName = customMetricName
            namespace = customMetricNamespace
            stat = "Maximum"
        }

    val anomalyDetectorRequest =
        PutAnomalyDetectorRequest {
            singleMetricAnomalyDetector = singleMetricAnomalyDetectorVal
        }

    CloudWatchClient { region = "us-east-1" }.use { cwClient ->
        cwClient.putAnomalyDetector(anomalyDetectorRequest)
        println("Added anomaly detector for metric $customMetricName.")
    }
}