diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
index f614d478e9..c79979173f 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-header.mustache
@@ -42,13 +42,15 @@ private:
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during Parameter parsing and validation.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleParsingException(const std::exception& ex) const noexcept;
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during processing of the request in handler functions.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleOperationException(const std::exception& ex) const noexcept;
 
diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-source.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-source.mustache
index 9814ba0cd6..dad2eb75c6 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-source.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/api-source.mustache
@@ -36,11 +36,13 @@ void {{classname}}::setupRoutes() {
 std::pair<Pistache::Http::Code, std::string> {{classname}}::handleParsingException(const std::exception& ex) const noexcept
 {
     try {
-        throw ex;
+        throw;
     } catch (nlohmann::detail::exception &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
     } catch ({{helpersNamespace}}::ValidationException &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
+    } catch (std::exception &e) {
+        return std::make_pair(Pistache::Http::Code::Internal_Server_Error, e.what())
     }
 }
 
diff --git a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
index cb6d8d98ee..656109b155 100644
--- a/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
+++ b/modules/openapi-generator/src/main/resources/cpp-pistache-server/model-header.mustache
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const {{classname}}& rhs) const;
     bool operator!=(const {{classname}}& rhs) const;
 
@@ -77,9 +83,6 @@ protected:
     {{#isEnum}}
     {{classname}}::e{{classname}} m_value = {{classname}}::e{{classname}}::INVALID_VALUE_OPENAPI_GENERATED;
     {{/isEnum}}
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace {{modelNamespace}}
diff --git a/samples/server/petstore/cpp-pistache/api/PetApi.cpp b/samples/server/petstore/cpp-pistache/api/PetApi.cpp
index 7b3641599e..a05048ec79 100644
--- a/samples/server/petstore/cpp-pistache/api/PetApi.cpp
+++ b/samples/server/petstore/cpp-pistache/api/PetApi.cpp
@@ -49,11 +49,13 @@ void PetApi::setupRoutes() {
 std::pair<Pistache::Http::Code, std::string> PetApi::handleParsingException(const std::exception& ex) const noexcept
 {
     try {
-        throw ex;
+        throw;
     } catch (nlohmann::detail::exception &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
     } catch (org::openapitools::server::helpers::ValidationException &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
+    } catch (std::exception &e) {
+        return std::make_pair(Pistache::Http::Code::Internal_Server_Error, e.what())
     }
 }
 
diff --git a/samples/server/petstore/cpp-pistache/api/PetApi.h b/samples/server/petstore/cpp-pistache/api/PetApi.h
index f689a0675e..3f790af02c 100644
--- a/samples/server/petstore/cpp-pistache/api/PetApi.h
+++ b/samples/server/petstore/cpp-pistache/api/PetApi.h
@@ -58,13 +58,15 @@ private:
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during Parameter parsing and validation.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleParsingException(const std::exception& ex) const noexcept;
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during processing of the request in handler functions.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleOperationException(const std::exception& ex) const noexcept;
 
diff --git a/samples/server/petstore/cpp-pistache/api/StoreApi.cpp b/samples/server/petstore/cpp-pistache/api/StoreApi.cpp
index ea0c0e1793..480bdcc033 100644
--- a/samples/server/petstore/cpp-pistache/api/StoreApi.cpp
+++ b/samples/server/petstore/cpp-pistache/api/StoreApi.cpp
@@ -45,11 +45,13 @@ void StoreApi::setupRoutes() {
 std::pair<Pistache::Http::Code, std::string> StoreApi::handleParsingException(const std::exception& ex) const noexcept
 {
     try {
-        throw ex;
+        throw;
     } catch (nlohmann::detail::exception &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
     } catch (org::openapitools::server::helpers::ValidationException &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
+    } catch (std::exception &e) {
+        return std::make_pair(Pistache::Http::Code::Internal_Server_Error, e.what())
     }
 }
 
diff --git a/samples/server/petstore/cpp-pistache/api/StoreApi.h b/samples/server/petstore/cpp-pistache/api/StoreApi.h
index 6eb2243874..e354a2710f 100644
--- a/samples/server/petstore/cpp-pistache/api/StoreApi.h
+++ b/samples/server/petstore/cpp-pistache/api/StoreApi.h
@@ -54,13 +54,15 @@ private:
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during Parameter parsing and validation.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleParsingException(const std::exception& ex) const noexcept;
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during processing of the request in handler functions.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleOperationException(const std::exception& ex) const noexcept;
 
diff --git a/samples/server/petstore/cpp-pistache/api/UserApi.cpp b/samples/server/petstore/cpp-pistache/api/UserApi.cpp
index 94903581dc..7b67dd0846 100644
--- a/samples/server/petstore/cpp-pistache/api/UserApi.cpp
+++ b/samples/server/petstore/cpp-pistache/api/UserApi.cpp
@@ -49,11 +49,13 @@ void UserApi::setupRoutes() {
 std::pair<Pistache::Http::Code, std::string> UserApi::handleParsingException(const std::exception& ex) const noexcept
 {
     try {
-        throw ex;
+        throw;
     } catch (nlohmann::detail::exception &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
     } catch (org::openapitools::server::helpers::ValidationException &e) {
         return std::make_pair(Pistache::Http::Code::Bad_Request, e.what());
+    } catch (std::exception &e) {
+        return std::make_pair(Pistache::Http::Code::Internal_Server_Error, e.what())
     }
 }
 
diff --git a/samples/server/petstore/cpp-pistache/api/UserApi.h b/samples/server/petstore/cpp-pistache/api/UserApi.h
index 003b6db4df..fadf0b046c 100644
--- a/samples/server/petstore/cpp-pistache/api/UserApi.h
+++ b/samples/server/petstore/cpp-pistache/api/UserApi.h
@@ -58,13 +58,15 @@ private:
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during Parameter parsing and validation.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleParsingException(const std::exception& ex) const noexcept;
 
     /// <summary>
     /// Helper function to handle unexpected Exceptions during processing of the request in handler functions.
-    /// May be overriden to return custom error formats.
+    /// May be overriden to return custom error formats. This is called inside a catch block.
+    /// Important: When overriding, do not call `throw ex;`, but instead use `throw;`.
     /// </summary>
     virtual std::pair<Pistache::Http::Code, std::string> handleOperationException(const std::exception& ex) const noexcept;
 
diff --git a/samples/server/petstore/cpp-pistache/model/ApiResponse.h b/samples/server/petstore/cpp-pistache/model/ApiResponse.h
index d963b76650..c4227b2187 100644
--- a/samples/server/petstore/cpp-pistache/model/ApiResponse.h
+++ b/samples/server/petstore/cpp-pistache/model/ApiResponse.h
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const ApiResponse& rhs) const;
     bool operator!=(const ApiResponse& rhs) const;
 
@@ -83,9 +89,6 @@ protected:
     bool m_TypeIsSet;
     std::string m_Message;
     bool m_MessageIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model
diff --git a/samples/server/petstore/cpp-pistache/model/Category.h b/samples/server/petstore/cpp-pistache/model/Category.h
index 1929ce33e9..71682c36c3 100644
--- a/samples/server/petstore/cpp-pistache/model/Category.h
+++ b/samples/server/petstore/cpp-pistache/model/Category.h
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const Category& rhs) const;
     bool operator!=(const Category& rhs) const;
 
@@ -74,9 +80,6 @@ protected:
     bool m_IdIsSet;
     std::string m_Name;
     bool m_NameIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model
diff --git a/samples/server/petstore/cpp-pistache/model/Order.h b/samples/server/petstore/cpp-pistache/model/Order.h
index 3d28e1eef6..86a6e35f87 100644
--- a/samples/server/petstore/cpp-pistache/model/Order.h
+++ b/samples/server/petstore/cpp-pistache/model/Order.h
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const Order& rhs) const;
     bool operator!=(const Order& rhs) const;
 
@@ -110,9 +116,6 @@ protected:
     bool m_StatusIsSet;
     bool m_Complete;
     bool m_CompleteIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model
diff --git a/samples/server/petstore/cpp-pistache/model/Pet.h b/samples/server/petstore/cpp-pistache/model/Pet.h
index 1cd841a08f..af773cb3e5 100644
--- a/samples/server/petstore/cpp-pistache/model/Pet.h
+++ b/samples/server/petstore/cpp-pistache/model/Pet.h
@@ -49,6 +49,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const Pet& rhs) const;
     bool operator!=(const Pet& rhs) const;
 
@@ -109,9 +115,6 @@ protected:
     bool m_TagsIsSet;
     std::string m_Status;
     bool m_StatusIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model
diff --git a/samples/server/petstore/cpp-pistache/model/Tag.h b/samples/server/petstore/cpp-pistache/model/Tag.h
index ddebeadae4..1b607e27fd 100644
--- a/samples/server/petstore/cpp-pistache/model/Tag.h
+++ b/samples/server/petstore/cpp-pistache/model/Tag.h
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const Tag& rhs) const;
     bool operator!=(const Tag& rhs) const;
 
@@ -74,9 +80,6 @@ protected:
     bool m_IdIsSet;
     std::string m_Name;
     bool m_NameIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model
diff --git a/samples/server/petstore/cpp-pistache/model/User.h b/samples/server/petstore/cpp-pistache/model/User.h
index 02bd5f4230..38048fe58e 100644
--- a/samples/server/petstore/cpp-pistache/model/User.h
+++ b/samples/server/petstore/cpp-pistache/model/User.h
@@ -46,6 +46,12 @@ public:
     /// </summary>
     bool validate(std::stringstream& msg) const;
 
+    /// <summary>
+    /// Helper overload for validate. Used when one model stores another model and calls it's validate.
+    /// Not meant to be called outside that case.
+    /// </summary>
+    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
+
     bool operator==(const User& rhs) const;
     bool operator!=(const User& rhs) const;
 
@@ -128,9 +134,6 @@ protected:
     bool m_PhoneIsSet;
     int32_t m_UserStatus;
     bool m_UserStatusIsSet;
-
-    // Helper overload for validate. Used when one model stores another model and calls it's validate.
-    bool validate(std::stringstream& msg, const std::string& pathPrefix) const;
 };
 
 } // namespace org::openapitools::server::model