3 files changed, 44 insertions, 4 deletions

diff --git a/src/WixToolset.Extensibility/BaseExtensionCommandLine.cs b/src/WixToolset.Extensibility/BaseExtensionCommandLine.cs
index 77e8a5bd..5f2ca109 100644
--- a/src/WixToolset.Extensibility/BaseExtensionCommandLine.cs
+++ b/src/WixToolset.Extensibility/BaseExtensionCommandLine.cs
@@ -9,7 +9,7 @@ namespace WixToolset.Extensibility
 
     public abstract class BaseExtensionCommandLine : IExtensionCommandLine
     {
-        public IEnumerable<ExtensionCommandLineSwitch> CommandLineSwitches => Enumerable.Empty<ExtensionCommandLineSwitch>();
+        public virtual IEnumerable<ExtensionCommandLineSwitch> CommandLineSwitches => Enumerable.Empty<ExtensionCommandLineSwitch>();
 
         public virtual void PostParse()
         {
@@ -24,7 +24,7 @@ namespace WixToolset.Extensibility
             return false;
         }
 
-        public virtual bool TryParseCommand(ICommandLineParser parser, out ICommandLineCommand command)
+        public virtual bool TryParseCommand(ICommandLineParser parser, string argument, out ICommandLineCommand command)
         {
             command = null;
             return false;
diff --git a/src/WixToolset.Extensibility/Data/ICommandLineCommand.cs b/src/WixToolset.Extensibility/Data/ICommandLineCommand.cs
index 1c6de205..a0fc9454 100644
--- a/src/WixToolset.Extensibility/Data/ICommandLineCommand.cs
+++ b/src/WixToolset.Extensibility/Data/ICommandLineCommand.cs
@@ -4,14 +4,33 @@ namespace WixToolset.Extensibility.Data
 {
     using WixToolset.Extensibility.Services;
 
+    /// <summary>
+    /// Custom command.
+    /// </summary>
     public interface ICommandLineCommand
     {
+        /// <summary>
+        /// Indicates the command-line should show the command-line logo.
+        /// </summary>
         bool ShowLogo { get; }
 
+        /// <summary>
+        /// Indicates the command-line parsing can stop.
+        /// </summary>
         bool StopParsing { get; }
 
+        /// <summary>
+        /// Executes the command.
+        /// </summary>
+        /// <returns>Exit code for the command.</returns>
         int Execute();
 
+        /// <summary>
+        /// Allows the command to parse command-line arguments.
+        /// </summary>
+        /// <param name="parser">Parser to help parse the argument and additional arguments.</param>
+        /// <param name="argument">Argument to parse.</param>
+        /// <returns>True if the argument is recognized; otherwise false to allow another extension to process it.</returns>
         bool TryParseArgument(ICommandLineParser parser, string argument); 
     }
 }
diff --git a/src/WixToolset.Extensibility/IExtensionCommandLine.cs b/src/WixToolset.Extensibility/IExtensionCommandLine.cs
index 0cbf84d9..45683373 100644
--- a/src/WixToolset.Extensibility/IExtensionCommandLine.cs
+++ b/src/WixToolset.Extensibility/IExtensionCommandLine.cs
@@ -7,7 +7,7 @@ namespace WixToolset.Extensibility
     using WixToolset.Extensibility.Services;
 
     /// <summary>
-    /// Interface extensions implement to be able to parse command-line options.
+    /// Interface extensions implement to be able to parse the command-line.
     /// </summary>
     public interface IExtensionCommandLine
     {
@@ -17,12 +17,33 @@ namespace WixToolset.Extensibility
         /// <value>The supported command line types for this extension.</value>
         IEnumerable<ExtensionCommandLineSwitch> CommandLineSwitches { get; }
 
+        /// <summary>
+        /// Called before the command-line is parsed.
+        /// </summary>
+        /// <param name="context">Information about the command-line to be parsed.</param>
         void PreParse(ICommandLineContext context);
 
+        /// <summary>
+        /// Gives the extension an opportunity pass a command-line argument for another command.
+        /// </summary>
+        /// <param name="parser">Parser to help parse the argument and additional arguments.</param>
+        /// <param name="argument">Argument to parse.</param>
+        /// <returns>True if the argument is recognized; otherwise false to allow another extension to process it.</returns>
         bool TryParseArgument(ICommandLineParser parser, string argument);
 
-        bool TryParseCommand(ICommandLineParser parser, out ICommandLineCommand command);
+        /// <summary>
+        /// Gives the extension an opportunity to provide a command.
+        /// </summary>
+        /// </summary>
+        /// <param name="parser">Parser to help parse the argument and additional arguments.</param>
+        /// <param name="argument">Argument to parse.</param>
+        /// <param name="command"></param>
+        /// <returns>True if the argument is recognized as a commond; otherwise false to allow another extension to process it.</returns>
+        bool TryParseCommand(ICommandLineParser parser, string argument, out ICommandLineCommand command);
 
+        /// <summary>
+        /// Called after the command-line is parsed.
+        /// </summary>
         void PostParse();
     }
 }