diff --git a/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/common_attributes.gen.ts b/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/common_attributes.gen.ts
index 6b6bc018c8e5c..0fc09348a2b1e 100644
--- a/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/common_attributes.gen.ts
+++ b/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/common_attributes.gen.ts
@@ -200,7 +200,7 @@ export type AlertsIndexNamespace = z.infer<typeof AlertsIndexNamespace>;
 export const AlertsIndexNamespace = z.string();
 
 export type MaxSignals = z.infer<typeof MaxSignals>;
-export const MaxSignals = z.number().int().min(1);
+export const MaxSignals = z.number().int().min(1).max(1000);
 
 export type ThreatSubtechnique = z.infer<typeof ThreatSubtechnique>;
 export const ThreatSubtechnique = z.object({
diff --git a/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/rule_request_schema.test.ts b/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/rule_request_schema.test.ts
index 0b89cbdc72889..a166f1ec0411d 100644
--- a/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/rule_request_schema.test.ts
+++ b/x-pack/plugins/security_solution/common/api/detection_engine/model/rule_schema/rule_request_schema.test.ts
@@ -483,6 +483,19 @@ describe('rules schema', () => {
     );
   });
 
+  test('max_signals cannot be greater than 1000', () => {
+    const payload: RuleCreateProps = {
+      ...getCreateRulesSchemaMock(),
+      max_signals: 1001,
+    };
+
+    const result = RuleCreateProps.safeParse(payload);
+    expectParseError(result);
+    expect(stringifyZodError(result.error)).toEqual(
+      'max_signals: Number must be less than or equal to 1000'
+    );
+  });
+
   test('max_signals can be 1', () => {
     const payload: RuleCreateProps = {
       ...getCreateRulesSchemaMock(),
diff --git a/x-pack/plugins/security_solution/public/common/hooks/use_app_toasts.ts b/x-pack/plugins/security_solution/public/common/hooks/use_app_toasts.ts
index 7a810fa9247d2..5a5601b3ffd09 100644
--- a/x-pack/plugins/security_solution/public/common/hooks/use_app_toasts.ts
+++ b/x-pack/plugins/security_solution/public/common/hooks/use_app_toasts.ts
@@ -129,7 +129,11 @@ export const appErrorToErrorStack = (error: AppError): Error => {
     : '';
   const stringifiedError = getStringifiedStack(error);
   const adaptedError = new Error(
-    `${String(error.body.message).trim() !== '' ? error.body.message : error.message} ${statusCode}`
+    postprocessErrorString(
+      `${
+        String(error.body.message).trim() !== '' ? error.body.message : error.message
+      } ${statusCode}`
+    )
   );
   // Note although all the Typescript typings say that error.name is a string and exists, we still can encounter an undefined so we
   // do an extra guard here and default to empty string if it is undefined
@@ -239,3 +243,8 @@ export const isEmptyObjectWhenStringified = (item: unknown): boolean => {
     return false;
   }
 };
+
+function postprocessErrorString(str: string): string {
+  // Remove the `[request body]` prefix added by Zod for request validation errors
+  return str.replace(/\[request body\]:/g, '');
+}