Index: src/Common/DelftTools.Shell.Core/Workflow/Activity.cs
===================================================================
diff -u -r5fc71a385897af92ccb092f2f969b5709afab85a -rc8d8f882d45f7e3cb5e47cb02106b7174f913856
--- src/Common/DelftTools.Shell.Core/Workflow/Activity.cs	(.../Activity.cs)	(revision 5fc71a385897af92ccb092f2f969b5709afab85a)
+++ src/Common/DelftTools.Shell.Core/Workflow/Activity.cs	(.../Activity.cs)	(revision c8d8f882d45f7e3cb5e47cb02106b7174f913856)
@@ -147,32 +147,44 @@
         }
 
         /// <summary>
-        /// Initializes internal state. Changes status to <see cref="ActivityStatus.Initialized"/>
+        /// Initializes internal state to prepare for execution. After calling this method,
+        /// <see cref="Status"/> will be set to <see cref="ActivityStatus.Initialized"/> if
+        /// no error has occurred.
         /// </summary>
+        /// <remarks>Set <see cref="Status"/> to <see cref="ActivityStatus.Failed"/>
+        /// when an error has occurred while performing the initialization.</remarks>
         protected abstract void OnInitialize();
 
         /// <summary>
-        /// Executes one step. Changes status to <see cref="ActivityStatus.Executed"/> or <see cref="ActivityStatus.Finished"/>.
+        /// Executes one step. This method will be called multiple times to allow for multiple
+        /// execution steps. After calling this method, <see cref="Status"/> will be set to 
+        /// <see cref="ActivityStatus.Executed"/> if no error has occurred.
         /// </summary>
+        /// <remarks>
+        /// <para>Set <see cref="Status"/> to <see cref="ActivityStatus.Failed"/>
+        /// when an error has occurred while executing.</para>
+        /// <para>Set <see cref="Status"/> to <see cref="ActivityStatus.Done"/>
+        /// when execution has finished without errors.</para>
+        /// </remarks>
         protected abstract void OnExecute();
 
         /// <summary>
-        /// Cancels current run. Changes status to <see cref="ActivityStatus.Cancelled"/>.
+        /// Activity has finished successfully. After calling this method, <see cref="Status"/> 
+        /// will be set to <see cref="ActivityStatus.Finished"/> if no error has occurred.
         /// </summary>
-        /// <returns>True when finished.</returns>
+        protected abstract void OnFinish();
+
+        /// <summary>
+        /// Cancels current run. <see cref="Status"/> will change to <see cref="ActivityStatus.Cancelled"/>
+        /// after this method has been called.
+        /// </summary>
         protected abstract void OnCancel();
 
         /// <summary>
         /// Performs clean-up of all internal resources.
         /// </summary>
-        /// <returns>True when finished.</returns>
         protected abstract void OnCleanUp();
 
-        /// <summary>
-        /// Activity has finished successfully.
-        /// </summary>
-        protected abstract void OnFinish();
-
         private void ChangeState(Action transitionAction, ActivityStatus statusBefore, ActivityStatus statusAfter)
         {
             try
Index: src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingCalculationInputsNodePresenter.cs
===================================================================
diff -u -r7b2fb7be49ba189d624e933485f14a7b94039bbb -rc8d8f882d45f7e3cb5e47cb02106b7174f913856
--- src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingCalculationInputsNodePresenter.cs	(.../PipingCalculationInputsNodePresenter.cs)	(revision 7b2fb7be49ba189d624e933485f14a7b94039bbb)
+++ src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingCalculationInputsNodePresenter.cs	(.../PipingCalculationInputsNodePresenter.cs)	(revision c8d8f882d45f7e3cb5e47cb02106b7174f913856)
@@ -33,7 +33,7 @@
         /// <summary>
         /// Injection points for a method to cause an <see cref="IActivity"/> to be scheduled for execution.
         /// </summary>
-        public Action<IActivity> RunActivityAction { get; set; }
+        public Action<IActivity> RunActivityAction { private get; set; }
 
         public void UpdateNode(ITreeNode parentNode, ITreeNode node, object nodeData)
         {
Index: src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingFailureMechanismNodePresenter.cs
===================================================================
diff -u -r2f6a4919a4b3a16f09d7da1c09223335eb261692 -rc8d8f882d45f7e3cb5e47cb02106b7174f913856
--- src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingFailureMechanismNodePresenter.cs	(.../PipingFailureMechanismNodePresenter.cs)	(revision 2f6a4919a4b3a16f09d7da1c09223335eb261692)
+++ src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Forms/NodePresenters/PipingFailureMechanismNodePresenter.cs	(.../PipingFailureMechanismNodePresenter.cs)	(revision c8d8f882d45f7e3cb5e47cb02106b7174f913856)
@@ -15,6 +15,10 @@
 
 namespace Ringtoets.Piping.Forms.NodePresenters
 {
+    /// <summary>
+    /// This class presents the data on <see cref="PipingFailureMechanism"/> as a node in a 
+    /// <see cref="ITreeView"/> and implements the way the user can interact with the node.
+    /// </summary>
     public class PipingFailureMechanismNodePresenter : ITreeNodePresenter
     {
         public ITreeView TreeView { get; set; }
Index: src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationActivity.cs
===================================================================
diff -u -r1a305404abc19e3cb419a32ff48b793391722d8b -rc8d8f882d45f7e3cb5e47cb02106b7174f913856
--- src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationActivity.cs	(.../PipingCalculationActivity.cs)	(revision 1a305404abc19e3cb419a32ff48b793391722d8b)
+++ src/Plugins/Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationActivity.cs	(.../PipingCalculationActivity.cs)	(revision c8d8f882d45f7e3cb5e47cb02106b7174f913856)
@@ -11,6 +11,10 @@
     {
         private readonly PipingData pipingData;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PipingCalculationActivity"/> class.
+        /// </summary>
+        /// <param name="pipingData">The piping data used for the calculation.</param>
         public PipingCalculationActivity(PipingData pipingData)
         {
             this.pipingData = pipingData;