diff --git a/src/snl/snl/kernel/SNLDesign.h b/src/snl/snl/kernel/SNLDesign.h
index 3bd524da..d74333bb 100644
--- a/src/snl/snl/kernel/SNLDesign.h
+++ b/src/snl/snl/kernel/SNLDesign.h
@@ -239,9 +239,31 @@ class SNLDesign final: public SNLObject {
     ///\return true if this SNLDesign is a top design.
     bool isTopDesign() const;
 
+    /**
+     * \brief Cloning interface for SNLDesign.
+     * \param name SNLName of the the clone.
+     * \return a new SNLDesign with the same interface as this SNLDesign.
+     */
     SNLDesign* cloneInterface(const SNLName& name=SNLName()) const;
+    /**
+     * \brief Cloning interface for SNLDesign to a specific SNLLibrary.
+     * \param library SNLLibrary where the clone will be created.
+     * \param name SNLName of the the clone.
+     * \return a new SNLDesign with the same interface as this SNLDesign.
+     */
     SNLDesign* cloneInterfaceToLibrary(SNLLibrary* library, const SNLName& name=SNLName()) const;
+    /**
+     * \brief Cloning for SNLDesign.
+     * \param name SNLName of the the clone.
+     * \return a new SNLDesign with the same interface and content as this SNLDesign.
+     */
     SNLDesign* clone(const SNLName& name=SNLName()) const;
+    /**
+     * \brief Cloning for SNLDesign to a specific SNLLibrary.
+     * \param library SNLLibrary where the clone will be created.
+     * \param name SNLName of the the clone.
+     * \return a new SNLDesign with the same interface and content as this SNLDesign.
+     */
     SNLDesign* cloneToLibrary(SNLLibrary* library, const SNLName& name=SNLName()) const;
 
     class CompareType {
diff --git a/src/snl/snl/kernel/SNLInstance.h b/src/snl/snl/kernel/SNLInstance.h
index 09f627c7..d77bee36 100644
--- a/src/snl/snl/kernel/SNLInstance.h
+++ b/src/snl/snl/kernel/SNLInstance.h
@@ -138,6 +138,10 @@ class SNLInstance final: public SNLDesignObject {
       SNLNet* net,
       SNLID::Bit netMSB, SNLID::Bit netLSB);
 
+    /**
+     * \brief Seting new model for this instance.
+     * \param newModel new model for this instance.
+     */
     void setModel(SNLDesign* newModel);
 
     SNLID::DesignObjectID getOrderID() const { return orederID_; }