diff --git a/api/pmt.yml b/api/pmt.yml
index 4069b30..9918049 100644
--- a/api/pmt.yml
+++ b/api/pmt.yml
@@ -180,12 +180,16 @@ paths:
       responses:
         204:
           description: "Employee successfully added to the specific Project"
+        401:
+          $ref: "#/components/responses/Unauthorized"
         404:
           $ref: "#/components/responses/NotFound"
         406:
           $ref: "#/components/responses/NotAcceptable"
         409:
             $ref: "#/components/responses/Conflict"
+        500:
+          $ref: "#/components/responses/InternalError"
 
     delete:
       operationId: "deleteProject"