diff --git a/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2021-10-01-preview/AlertRules.json b/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2021-10-01-preview/AlertRules.json
index 7b0ab31b7605..f2d0da33aa61 100644
--- a/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2021-10-01-preview/AlertRules.json
+++ b/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2021-10-01-preview/AlertRules.json
@@ -991,6 +991,19 @@
           "description": "Determines whether this alert rule is enabled or disabled.",
           "type": "boolean"
         },
+        "sourceSettings": {
+          "description": "Configuration for all supported source signals in fusion detection.",
+          "items": {
+            "$ref": "#/definitions/FusionSourceSettings"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        },
+        "scenarioExclusionPatterns": {
+          "description": "Configuration to exclude scenarios in fusion detection.",
+          "$ref": "#/definitions/FusionScenarioExclusionPattern",
+          "type": "object"
+        },
         "lastModifiedUtc": {
           "description": "The last time that this alert has been modified.",
           "format": "date-time",
@@ -1025,6 +1038,128 @@
       ],
       "type": "object"
     },
+    "FusionSourceSettings": {
+      "description": "Represents a supported source signal configuration in Fusion detection.",
+      "properties": {
+        "enabled": {
+          "description": "Determines whether this source signal is enabled or disabled in Fusion detection.",
+          "type": "boolean"
+        },
+        "sourceName": {
+          "description": "Name of the Fusion source signal. Refer to Fusion alert rule template for supported values.",
+          "type": "string"
+        },
+        "sourceSubTypes": {
+          "description": "Configuration for all source subtypes under this source signal consumed in fusion detection.",
+          "items": {
+            "$ref": "#/definitions/FusionSourceSubTypeSetting"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        }
+      },
+      "required": [
+        "enabled",
+        "sourceName"
+      ],
+      "type": "object"
+    },
+    "FusionSourceSubTypeSetting": {
+      "description": "Represents a supported source subtype configuration under a source signal in Fusion detection.",
+      "properties": {
+        "enabled": {
+          "description": "Determines whether this source subtype under source signal is enabled or disabled in Fusion detection.",
+          "type": "boolean"
+        },
+        "sourceSubTypeName": {
+          "description": "The Name of the source subtype under a given source signal in Fusion detection. Refer to Fusion alert rule template for supported values.",
+          "type": "string"
+        },
+        "severityFilters": {
+          "description": "Severity configuration for a source subtype consumed in fusion detection.",
+          "$ref": "#/definitions/FusionSubTypeSeverityFilter",
+          "type": "object"
+        }
+      },
+      "required": [
+        "enabled",
+        "sourceSubTypeName",
+        "severityFilters"
+      ],
+      "type": "object"
+    },
+    "FusionSubTypeSeverityFilter": {
+      "description": "Represents severity configuration for a source subtype consumed in Fusion detection.",
+      "properties": {
+        "isSupported": {
+          "description": "Determines whether this source subtype supports severity configuration or not.",
+          "type": "boolean",
+          "readOnly": true
+        },
+        "filters": {
+          "description": "Individual Severity configuration settings for a given source subtype consumed in Fusion detection.",
+          "items": {
+            "$ref": "#/definitions/FusionSubTypeSeverityFiltersItem"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        }
+      },
+      "type": "object"
+    },
+    "FusionSubTypeSeverityFiltersItem": {
+      "description": "Represents a Severity filter setting for a given source subtype consumed in Fusion detection.",
+      "properties": {
+        "severity": {
+          "$ref": "./common/AlertTypes.json#/definitions/AlertSeverityEnum",
+          "description": "The Severity for a given source subtype consumed in Fusion detection."
+        },
+        "enabled": {
+          "description": "Determines whether this severity is enabled or disabled for this source subtype consumed in Fusion detection.",
+          "type": "boolean"
+        }
+      },
+      "required": [
+        "severity",
+        "enabled"
+      ],
+      "type": "object"
+    },
+    "FusionScenarioExclusionPattern": {
+      "description": "Represents Fusion scenario exclusion patterns in Fusion detection.",
+      "properties": {
+        "scenarioExclusionPatterns": {
+          "description": "Individual scenario exclusion pattern.",
+          "items": {
+            "$ref": "#/definitions/FusionScenarioExclusionPatternItem"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        }
+      },
+      "required": [
+        "scenarioExclusionPatterns"
+      ],
+      "type": "object"
+    },
+    "FusionScenarioExclusionPatternItem": {
+      "description": "Represents individual Fusion scenario exclusion pattern in Fusion detection.",
+      "properties": {
+        "exclusionPattern": {
+          "description": "Scenario exclusion pattern.",
+          "type": "string"
+        },
+        "dateAddedInUTC": {
+          "description": "DateTime in UTC.",
+          "type": "string"
+        }
+      },
+      "required": [
+        "exclusionPattern",
+        "dateAddedInUTC"
+      ],
+      "type": "object"
+    },
     "FusionAlertRuleTemplate": {
       "allOf": [
         {
@@ -1046,11 +1181,21 @@
               "description": "The severity for alerts created by this alert rule."
             }
           },
+          "sourceSettings": 
+          {
+            "description": "All supported source signal configurations consumed in fusion detection.",
+            "items": {
+              "$ref": "#/definitions/FusionTemplateSourceSetting"
+            },
+            "x-ms-identifiers": [],
+            "type": "array"
+          },
           "required": [
             "displayName",
             "description",
             "status",
             "severity",
+            "sourceSettings",
             "alertRulesCreatedByTemplateCount"
           ],
           "type": "object",
@@ -1060,6 +1205,68 @@
       "type": "object",
       "x-ms-discriminator-value": "Fusion"
     },
+    "FusionTemplateSourceSetting": {
+      "description": "Represents a source signal consumed in Fusion detection.",
+      "properties": {
+        "sourceName": {
+          "description": "The name of a source signal consumed in Fusion detection.",
+          "type": "string"
+        },
+        "sourceSubTypes": {
+          "description": "All supported source subtypes under this source signal consumed in fusion detection.",
+          "items": {
+            "$ref": "#/definitions/FusionTemplateSourceSubType"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        }
+      },
+      "required": [
+        "sourceName",
+        "sourceSubTypes"
+      ],
+      "type": "object"
+    },
+    "FusionTemplateSourceSubType": {
+      "description": "Represents a source subtype under a source signal consumed in Fusion detection.",
+      "properties": {
+        "sourceSubTypeName": {
+          "description": "The name of source subtype under a source signal consumed in Fusion detection.",
+          "type": "string"
+        },
+        "severityFilter": {
+          "description": "Severity configuration available for a source subtype consumed in fusion detection.",
+          "$ref": "#/definitions/FusionTemplateSubTypeSeverityFilter",
+          "type": "object"
+        }
+      },
+      "required": [
+        "sourceSubTypeName",
+        "severityFilter"
+      ],
+      "type": "object"
+    },
+    "FusionTemplateSubTypeSeverityFilter": {
+      "description": "Represents severity configurations available for a source subtype consumed in Fusion detection.",
+      "properties": {
+        "isSupported": {
+          "description": "Determines whether severity configuration is supported for this source subtype consumed in Fusion detection.",
+          "type": "boolean"
+        },
+        "severityFilters": {
+          "description": "List of all supported severities for this source subtype consumed in Fusion detection.",
+          "items": {
+            "$ref": "./common/AlertTypes.json#/definitions/AlertSeverityEnum"
+          },
+          "x-ms-identifiers": [],
+          "type": "array"
+        }
+      },
+      "required": [
+        "isSupported"
+      ],
+      "type": "object"
+    },
     "ThreatIntelligenceAlertRule": {
       "allOf": [
         {