diff --git a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/ReadCommand.cs b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/ReadCommand.cs
index 36a43ae..0286df2 100644
--- a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/ReadCommand.cs
+++ b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/ReadCommand.cs
@@ -19,9 +19,12 @@ public sealed class ReadCommand : S7CommandBase
         IsRequired = true)]
     public string Address { get; init; } = default!;
 
+    // Driver.S7.Cli-002: help text trimmed to the types the driver actually implements.
+    // Int64 / UInt64 / Float64 / String / DateTime are defined in S7DataType but the driver
+    // raises NotSupportedException (→ BadNotSupported) on reads of those types.
     [CommandOption("type", 't', Description =
-        "Bool / Byte / Int16 / UInt16 / Int32 / UInt32 / Int64 / UInt64 / Float32 / Float64 / " +
-        "String / DateTime (default Int16).")]
+        "Bool / Byte / Int16 / UInt16 / Int32 / UInt32 / Float32 (default Int16). " +
+        "Int64, UInt64, Float64, String, and DateTime are not yet implemented and will return BadNotSupported.")]
     public S7DataType DataType { get; init; } = S7DataType.Int16;
 
     [CommandOption("string-length", Description =
diff --git a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/SubscribeCommand.cs b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/SubscribeCommand.cs
index e69e586..dbe5983 100644
--- a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/SubscribeCommand.cs
+++ b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/SubscribeCommand.cs
@@ -15,9 +15,10 @@ public sealed class SubscribeCommand : S7CommandBase
     [CommandOption("address", 'a', Description = "S7 address — same format as `read`.", IsRequired = true)]
     public string Address { get; init; } = default!;
 
+    // Driver.S7.Cli-002: help text trimmed to the types the driver actually implements.
     [CommandOption("type", 't', Description =
-        "Bool / Byte / Int16 / UInt16 / Int32 / UInt32 / Int64 / UInt64 / Float32 / Float64 / " +
-        "String / DateTime (default Int16).")]
+        "Bool / Byte / Int16 / UInt16 / Int32 / UInt32 / Float32 (default Int16). " +
+        "Int64, UInt64, Float64, String, and DateTime are not yet implemented and will return BadNotSupported.")]
     public S7DataType DataType { get; init; } = S7DataType.Int16;
 
     [CommandOption("interval-ms", 'i', Description = "Publishing interval ms (default 1000).")]