diff --git a/BizHawk.Client.ApiHawk/Attributes/BizHawkExternalToolUsageAttribute.cs b/BizHawk.Client.ApiHawk/Attributes/BizHawkExternalToolUsageAttribute.cs
index 0c15e79c1a..2f244bf513 100644
--- a/BizHawk.Client.ApiHawk/Attributes/BizHawkExternalToolUsageAttribute.cs
+++ b/BizHawk.Client.ApiHawk/Attributes/BizHawkExternalToolUsageAttribute.cs
@@ -11,12 +11,10 @@ namespace BizHawk.Client.ApiHawk
 	{
 		#region cTor(s)
 
-		/// <summary>
-		/// Initialize a new instance of <see cref="BizHawkExternalToolUsageAttribute"/>
-		/// </summary>
-		/// <param name="usage"><see cref="BizHawkExternalToolUsage"/> i.e. what your external tool is for</param>
-		/// <param name="system"><see cref="CoreSystem"/> that your external tool is used for</param>
-		/// <param name="gameHash">The game hash, unique game ID (see in the game database)</param>
+		/// <exception cref="InvalidOperationException">
+		/// <paramref name="usage"/> is <see cref="BizHawkExternalToolUsage.EmulatorSpecific"/> and <paramref name="system"/> is <see cref="CoreSystem.Null"/>, or
+		/// usage is <see cref="BizHawkExternalToolUsage.GameSpecific"/> and <paramref name="gameHash"/> is blank
+		/// </exception>
 		public BizHawkExternalToolUsageAttribute(BizHawkExternalToolUsage usage, CoreSystem system, string gameHash)
 		{
 			if (usage == BizHawkExternalToolUsage.EmulatorSpecific && system == CoreSystem.Null)
diff --git a/BizHawk.Client.ApiHawk/Classes/BasicApiProvider.cs b/BizHawk.Client.ApiHawk/Classes/BasicApiProvider.cs
index 1d35d3cb54..293777e9b8 100644
--- a/BizHawk.Client.ApiHawk/Classes/BasicApiProvider.cs
+++ b/BizHawk.Client.ApiHawk/Classes/BasicApiProvider.cs
@@ -30,10 +30,9 @@ namespace BizHawk.Client.ApiHawk
 			_apis = libs;
 		}
 
-		/// <summary>
-		/// the client can call this to register an additional Api
-		/// </summary>
-		/// <typeparam name="T">The <seealso cref="IExternalApi"/> to register</typeparam>
+		/// <summary>the client can call this to register an additional API</summary>
+		/// <typeparam name="T">the type, inheriting <see cref="IExternalApi"/>, to be registered</typeparam>
+		/// <exception cref="ArgumentNullException"><paramref name="api"/> is null</exception>
 		public void Register<T>(T api)
 			where T : IExternalApi
 		{
diff --git a/BizHawk.Client.ApiHawk/Classes/Joypad.cs b/BizHawk.Client.ApiHawk/Classes/Joypad.cs
index 927c855803..2e2391190b 100644
--- a/BizHawk.Client.ApiHawk/Classes/Joypad.cs
+++ b/BizHawk.Client.ApiHawk/Classes/Joypad.cs
@@ -25,6 +25,7 @@ namespace BizHawk.Client.ApiHawk
 		/// </summary>
 		/// <param name="system">What <see cref="SystemInfo"/> this <see cref="Joypad"/> is used for</param>
 		/// <param name="player">Which player this controller is assigned to</param>
+		/// <exception cref="IndexOutOfRangeException"><paramref name="player"/> not in range <c>1..max</c> where <c>max</c> is <paramref name="system"/>.<see cref="SystemInfo.MaxControllers"/></exception>
 		internal Joypad(SystemInfo system, int player)
 		{
 			if (player < 1 || player > system.MaxControllers)