diff --git a/src/adapters/node-http/core.ts b/src/adapters/node-http/core.ts
index 6982704a..aa04b980 100644
--- a/src/adapters/node-http/core.ts
+++ b/src/adapters/node-http/core.ts
@@ -173,6 +173,7 @@ export const createOpenApiNodeHttpHandler = <
       const statusCode = meta?.status ?? TRPC_ERROR_CODE_HTTP_STATUS[error.code] ?? 500;
       const headers = meta?.headers ?? {};
       const body: OpenApiErrorResponse = {
+        ...errorShape, // Pass the error through
         message: isInputValidationError
           ? 'Input validation failed'
           : errorShape?.message ?? error.message ?? 'An error occurred',
diff --git a/src/generator/schema.ts b/src/generator/schema.ts
index 430dc38b..78f9e816 100644
--- a/src/generator/schema.ts
+++ b/src/generator/schema.ts
@@ -140,43 +140,54 @@ export const getRequestBodyObject = (
 export const hasInputs = (schema: unknown) =>
   instanceofZodType(schema) && !instanceofZodTypeLikeVoid(unwrapZodType(schema, true));
 
+const errorResponseObjectByCode: Record<string, ZodOpenApiResponseObject> = {};
+
 export const errorResponseObject = (
-  code?: string,
+  code = 'INTERNAL_SERVER_ERROR',
   message?: string,
   issues?: { message: string }[],
-): ZodOpenApiResponseObject => ({
-  description: message ?? 'An error response',
-  content: {
-    'application/json': {
-      schema: z
-        .object({
-          message: z.string().openapi({
-            description: 'The error message',
-            example: message ?? 'Internal server error',
-          }),
-          code: z
-            .string()
-            .openapi({ description: 'The error code', example: code ?? 'INTERNAL_SERVER_ERROR' }),
-          issues: z
-            .array(z.object({ message: z.string() }))
-            .optional()
+): ZodOpenApiResponseObject => {
+  if (!errorResponseObjectByCode[code]) {
+    errorResponseObjectByCode[code] = {
+      description: message ?? 'An error response',
+      content: {
+        'application/json': {
+          schema: z
+            .object({
+              message: z.string().openapi({
+                description: 'The error message',
+                example: message ?? 'Internal server error',
+              }),
+              code: z
+                .string()
+                .openapi({
+                  description: 'The error code',
+                  example: code ?? 'INTERNAL_SERVER_ERROR',
+                }),
+              issues: z
+                .array(z.object({ message: z.string() }))
+                .optional()
+                .openapi({
+                  description: 'An array of issues that were responsible for the error',
+                  example: issues ?? [],
+                }),
+            })
             .openapi({
-              description: 'An array of issues that were responsible for the error',
-              example: issues ?? [],
+              title: 'Error',
+              description: 'The error information',
+              example: {
+                code: code ?? 'INTERNAL_SERVER_ERROR',
+                message: message ?? 'Internal server error',
+                issues: issues ?? [],
+              },
+              ref: `error.${code}`,
             }),
-        })
-        .openapi({
-          title: 'Error',
-          description: 'The error information',
-          example: {
-            code: code ?? 'INTERNAL_SERVER_ERROR',
-            message: message ?? 'Internal server error',
-            issues: issues ?? [],
-          },
-        }),
-    },
-  },
-});
+        },
+      },
+    };
+  }
+  return errorResponseObjectByCode[code]!;
+};
 
 export const getResponsesObject = (
   schema: ZodTypeAny,
diff --git a/src/types.ts b/src/types.ts
index 9a5e6599..a24b120f 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,7 +1,7 @@
 import { Procedure, ProcedureParams, Router } from '@trpc/server';
 import type { RootConfig } from '@trpc/server/dist/core/internals/config';
-import { TRPC_ERROR_CODE_KEY } from '@trpc/server/rpc';
-import type { RouterDef } from '@trpc/server/src/core/router';
+import type { RouterDef } from '@trpc/server/dist/core/router';
+import { TRPC_ERROR_CODE_KEY } from '@trpc/server/dist/rpc';
 import {
   AnyZodObject,
   ZodBigInt,
diff --git a/src/utils/zod.ts b/src/utils/zod.ts
index d4bb29cb..1422caba 100644
--- a/src/utils/zod.ts
+++ b/src/utils/zod.ts
@@ -32,6 +32,19 @@ export const instanceofZodTypeLikeVoid = (type: z.ZodTypeAny): type is ZodTypeLi
 };
 
 export const unwrapZodType = (type: z.ZodTypeAny, unwrapPreprocess: boolean): z.ZodTypeAny => {
+  // TODO: Allow parsing array query params
+  // if (instanceofZodTypeKind(type, z.ZodFirstPartyTypeKind.ZodArray)) {
+  //   return unwrapZodType(type.element, unwrapPreprocess);
+  // }
+  if (instanceofZodTypeKind(type, z.ZodFirstPartyTypeKind.ZodEnum)) {
+    return unwrapZodType(z.string(), unwrapPreprocess);
+  }
+  if (instanceofZodTypeKind(type, z.ZodFirstPartyTypeKind.ZodNullable)) {
+    return unwrapZodType(type.unwrap(), unwrapPreprocess);
+  }
+  if (instanceofZodTypeKind(type, z.ZodFirstPartyTypeKind.ZodBranded)) {
+    return unwrapZodType(type.unwrap(), unwrapPreprocess);
+  }
   if (instanceofZodTypeKind(type, z.ZodFirstPartyTypeKind.ZodOptional)) {
     return unwrapZodType(type.unwrap(), unwrapPreprocess);
   }