diff --git a/packages/whook-cors/src/__snapshots__/index.test.js.snap b/packages/whook-cors/src/__snapshots__/index.test.js.snap
index 063f62da..1bc2c71e 100644
--- a/packages/whook-cors/src/__snapshots__/index.test.js.snap
+++ b/packages/whook-cors/src/__snapshots__/index.test.js.snap
@@ -45,16 +45,24 @@ Object {
     },
     "/users/{userid}": Object {
       "head": Object {
-        "operationId": "ping",
+        "operationId": "getUser",
         "parameters": Array [
           Object {
             "in": "path",
             "name": "userId",
+            "required": true,
             "type": "number",
           },
           Object {
             "in": "query",
             "name": "full",
+            "required": true,
+            "type": "boolean",
+          },
+          Object {
+            "in": "query",
+            "name": "retry",
+            "required": false,
             "type": "boolean",
           },
         ],
@@ -63,7 +71,7 @@ Object {
             "description": "The user",
           },
         },
-        "summary": "Checks API's availability.",
+        "summary": "Return a user.",
       },
       "options": Object {
         "operationId": "optionsWithCORS",
@@ -71,11 +79,19 @@ Object {
           Object {
             "in": "path",
             "name": "userId",
+            "required": true,
             "type": "number",
           },
           Object {
             "in": "query",
             "name": "full",
+            "required": false,
+            "type": "boolean",
+          },
+          Object {
+            "in": "query",
+            "name": "retry",
+            "required": false,
             "type": "boolean",
           },
         ],
@@ -90,7 +106,7 @@ Object {
         ],
         "x-whook": Object {
           "private": true,
-          "sourceOperationId": "ping",
+          "sourceOperationId": "getUser",
           "suffix": "CORS",
           "type": "http",
         },
diff --git a/packages/whook-cors/src/index.js b/packages/whook-cors/src/index.js
index e44c29dc..1cac1fdb 100644
--- a/packages/whook-cors/src/index.js
+++ b/packages/whook-cors/src/index.js
@@ -48,7 +48,16 @@ export async function augmentAPIWithCORS(API) {
   const operations = await getOpenAPIOperations(await flattenOpenAPI(API));
 
   return operations.reduce((newAPI, operation) => {
+    if ('options' === operation.method) {
+      return newAPI;
+    }
+
     const existingOperation = newAPI.paths[operation.path].options;
+
+    if (existingOperation) {
+      return newAPI;
+    }
+
     const whookConfig = {
       type: 'http',
       ...(operation['x-whook'] || {}),
@@ -60,12 +69,6 @@ export async function augmentAPIWithCORS(API) {
     if (whookConfig.type !== 'http') {
       return newAPI;
     }
-    if ('options' === operation.method) {
-      return newAPI;
-    }
-    if (existingOperation) {
-      return newAPI;
-    }
 
     newAPI.paths[operation.path].options = {
       operationId: 'optionsWithCORS',
@@ -74,9 +77,14 @@ export async function augmentAPIWithCORS(API) {
       'x-whook': {
         ...whookConfig,
       },
-      parameters: (operation.parameters || []).filter(
-        parameter => 'path' === parameter.in || 'query' === parameter.in,
-      ),
+      parameters: (operation.parameters || [])
+        .filter(
+          parameter => 'path' === parameter.in || 'query' === parameter.in,
+        )
+        .map(parameter => ({
+          ...parameter,
+          required: 'path' === parameter.in,
+        })),
       responses: {
         200: {
           description: 'CORS sent.',
diff --git a/packages/whook-cors/src/index.test.js b/packages/whook-cors/src/index.test.js
index 2b5ee9cb..46f334e7 100644
--- a/packages/whook-cors/src/index.test.js
+++ b/packages/whook-cors/src/index.test.js
@@ -89,18 +89,26 @@ describe('augmentAPIWithCORS()', () => {
           },
           '/users/{userid}': {
             head: {
-              operationId: 'ping',
-              summary: "Checks API's availability.",
+              operationId: 'getUser',
+              summary: 'Return a user.',
               parameters: [
                 {
                   in: 'path',
                   name: 'userId',
                   type: 'number',
+                  required: true,
                 },
                 {
                   in: 'query',
                   name: 'full',
                   type: 'boolean',
+                  required: true,
+                },
+                {
+                  in: 'query',
+                  name: 'retry',
+                  type: 'boolean',
+                  required: false,
                 },
               ],
               responses: {