diff --git a/interfaces/IContentProtection.h b/interfaces/IContentProtection.h
index c883c4ef..db0e2f60 100644
--- a/interfaces/IContentProtection.h
+++ b/interfaces/IContentProtection.h
@@ -24,7 +24,7 @@
 namespace Thunder {
 namespace Exchange {
 
-    // @json 1.0.0
+    // @json 1.0.0 @text:keep
     struct EXTERNAL IContentProtection : virtual public Core::IUnknown {
         enum { ID = ID_CONTENTPROTECTION };
 
@@ -59,25 +59,21 @@ namespace Exchange {
                 State state;
                 // @brief same as that returned by the SecManager.
                 // For other cases greater than 20000 (e.g. 2)
-                // @text failureReason
                 int32_t failureReason;
             };
 
-            // @alt onWatermarkStatusChanged
+            // @text onWatermarkStatusChanged
             // @param sessionId session id for the content protection session
-            // (e.g. 930762523)
+            // (e.g. "930762523")
             // @param appId application that should receive the notification
-            virtual void WatermarkStatusChanged(
-                uint32_t sessionId /* @text:sessionId */,
-                const string& appId /* @text:appId */,
-                const Status& status)
-                = 0;
+            virtual void WatermarkStatusChanged(const string& sessionId,
+                const string& appId, const Status& status) = 0;
         };
 
-        virtual uint32_t Register(INotification* notification) = 0;
-        virtual uint32_t Unregister(INotification* notification) = 0;
+        virtual Core::hresult Register(INotification* notification) = 0;
+        virtual Core::hresult Unregister(INotification* notification) = 0;
 
-        // @alt openDrmSession
+        // @text openDrmSession
         // @param clientId client that establishes the playback session
         // (e.g. "com.comcast.vipa:1")
         // @param appId application requesting the new watermarking session
@@ -85,7 +81,7 @@ namespace Exchange {
         // @param initData video platform specific init data
         // (e.g. "{\"sessionConfiguration\":{\"distributedTraceId\":\"...\"},\"accessToken\":\"...\",\"contentMetadata\":\"...\"}")
         // @param sessionId generated by SecManager to track sessions
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @param response video platform specific response data
         // (e.g. "{\"license\":\"...\",\"refreshDuration\":0}")
         // @retval 21002 Invalid aspect dimension
@@ -111,28 +107,23 @@ namespace Exchange {
         // @retval 23003 Watermark request timeout
         // @retval 23012 Watermark memory allocation error
         // @retval 23014 Watermark perceptibility error
-        virtual uint32_t OpenDrmSession(
-            const string& clientId /* @text:clientId */,
-            const string& appId /* @text:appId */,
-            KeySystem keySystem /* @text:keySystem */,
-            const string& licenseRequest /* @text:licenseRequest */,
-            const string& initData /* @text:initData */,
-            uint32_t& sessionId /* @text:sessionId @out */,
-            string& response /* @text:openSessionResponse @out */)
-            = 0;
-
-        // @alt setDrmSessionState
+        virtual Core::hresult OpenDrmSession(
+            const string& clientId, const string& appId,
+            KeySystem keySystem,
+            const string& licenseRequest, const string& initData,
+            string& sessionId /* @out */,
+            string& response /* @text:openSessionResponse @out */) = 0;
+
+        // @text setDrmSessionState
         // @param sessionId sec manager generated playback session id
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @retval 21009 Invalid session id
-        virtual uint32_t SetDrmSessionState(
-            uint32_t sessionId /* @text:sessionId */,
-            State sessionState /* @text:sessionState */)
-            = 0;
+        virtual Core::hresult SetDrmSessionState(const string& sessionId,
+            State sessionState) = 0;
 
-        // @alt updateDrmSession
+        // @text updateDrmSession
         // @param sessionId sec manager generated playback session id
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @param licenseRequest base64-encoded DRM license request
         // @param initData video platform specific init data
         // (e.g. "{\"sessionConfiguration\":{\"distributedTraceId\":\"...\"},\"accessToken\":\"...\",\"contentMetadata\":\"...\"}")
@@ -161,43 +152,44 @@ namespace Exchange {
         // @retval 23003 Watermark request timeout
         // @retval 23012 Watermark memory allocation error
         // @retval 23014 Watermark perceptibility error
-        virtual uint32_t UpdateDrmSession(
-            uint32_t sessionId /* @text:sessionId */,
-            const string& licenseRequest /* @text:licenseRequest */,
-            const string& initData /* @text:initData */,
-            string& response /* @text:updateSessionResponse @out */)
-            = 0;
-
-        // @alt closeDrmSession
+        virtual Core::hresult UpdateDrmSession(const string& sessionId,
+            const string& licenseRequest, const string& initData,
+            string& response /* @text:updateSessionResponse @out */) = 0;
+
+        // @text closeDrmSession
         // @param sessionId sec manager generated playback session id
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @param response video platform specific response data
         // @retval 21009 Invalid session id
         // @retval 21012 Invalid client id
-        virtual uint32_t CloseDrmSession(
-            uint32_t sessionId /* @text:sessionId */,
-            string& response /* @text:closeSessionResponse @out */)
-            = 0;
+        virtual Core::hresult CloseDrmSession(const string& sessionId,
+            string& response /* @text:closeSessionResponse @out */) = 0;
 
-        // @alt showWatermark
+        // @text showWatermark
         // @param sessionId id returned on a call to openDrmSession
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @param show true when watermark has to be presented
-        virtual uint32_t ShowWatermark(
-            uint32_t sessionId /* @text:sessionId */,
-            bool show,
-            const uint8_t opacityLevel /* @text:opacityLevel @restrict:0..100 */)
-            = 0;
+        virtual Core::hresult ShowWatermark(const string& sessionId,
+            bool show, const uint8_t opacityLevel /* @restrict:0..100 */) = 0;
 
-        // @alt setPlaybackPosition
+        // @text setPlaybackPosition
         // @param sessionId sec manager generated playback session id
-        // (e.g. 930762523)
+        // (e.g. "930762523")
         // @param speed current playback speed
         // @param position current playback position
-        virtual uint32_t SetPlaybackPosition(
-            uint32_t sessionId /* @text:sessionId */,
-            int32_t speed, long position)
-            = 0;
+        virtual Core::hresult SetPlaybackPosition(const string& sessionId,
+            int32_t speed, long position) = 0;
+    };
+
+    // @json 1.0.0 @text:keep
+    struct EXTERNAL IErrorToString : virtual public Core::IUnknown {
+        enum { ID = ID_ERRORTOSTRING };
+
+        ~IErrorToString() override = default;
+
+        // @text errorToString
+        virtual Core::hresult ErrorToString(
+            const int32_t code, string& result /* @out */) const = 0;
     };
 
 } // namespace Exchange
diff --git a/interfaces/Ids.h b/interfaces/Ids.h
index 9ddb0bb4..18e63e70 100644
--- a/interfaces/Ids.h
+++ b/interfaces/Ids.h
@@ -387,6 +387,7 @@ namespace Exchange {
 
         ID_CONTENTPROTECTION = RPC::IDS::ID_EXTERNAL_INTERFACE_OFFSET + 0x500,
         ID_CONTENTPROTECTION_NOTIFICATION = ID_CONTENTPROTECTION + 1,
+        ID_ERRORTOSTRING = ID_CONTENTPROTECTION + 2,
 
         ID_WATERMARK = RPC::IDS::ID_EXTERNAL_INTERFACE_OFFSET + 0x510,
         ID_WATERMARK_NOTIFICATION = ID_WATERMARK + 2,