diff --git a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/WriteCommand.cs b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/WriteCommand.cs
index bc84d52..3e2256b 100644
--- a/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/WriteCommand.cs
+++ b/src/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli/Commands/WriteCommand.cs
@@ -18,9 +18,13 @@ public sealed class WriteCommand : S7CommandBase
         "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.
+    // Int64 / UInt64 / Float64 / String / DateTime are defined in S7DataType but the driver
+    // raises NotSupportedException (→ BadNotSupported) on any read/write of those types;
+    // advertising them misleads operators who then see BadNotSupported with no explanation.
     [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("value", 'v', Description =
@@ -62,22 +66,44 @@ public sealed class WriteCommand : S7CommandBase
     }
 
     /// <summary>Parse <c>--value</c> per <see cref="S7DataType"/>, invariant culture throughout.</summary>
-    internal static object ParseValue(string raw, S7DataType type) => type switch
+    /// <remarks>
+    ///     Driver.S7.Cli-001: numeric and <see cref="DateTime"/> parses are wrapped so that
+    ///     malformed input (<see cref="FormatException"/> / <see cref="OverflowException"/>)
+    ///     surfaces as a clean <see cref="CliFx.Exceptions.CommandException"/> rather than a
+    ///     raw .NET stack trace — matching the friendly message the Bool path already produces.
+    /// </remarks>
+    internal static object ParseValue(string raw, S7DataType type)
     {
-        S7DataType.Bool => ParseBool(raw),
-        S7DataType.Byte => byte.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.Int16 => short.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.UInt16 => ushort.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.Int32 => int.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.UInt32 => uint.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.Int64 => long.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.UInt64 => ulong.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.Float32 => float.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.Float64 => double.Parse(raw, CultureInfo.InvariantCulture),
-        S7DataType.String => raw,
-        S7DataType.DateTime => DateTime.Parse(raw, CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind),
-        _ => throw new CliFx.Exceptions.CommandException($"Unsupported DataType '{type}' for write."),
-    };
+        if (type == S7DataType.Bool) return ParseBool(raw);
+        if (type == S7DataType.String) return raw;
+        try
+        {
+            return type switch
+            {
+                S7DataType.Byte     => (object)byte.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.Int16    => (object)short.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.UInt16   => (object)ushort.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.Int32    => (object)int.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.UInt32   => (object)uint.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.Int64    => (object)long.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.UInt64   => (object)ulong.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.Float32  => (object)float.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.Float64  => (object)double.Parse(raw, CultureInfo.InvariantCulture),
+                S7DataType.DateTime => (object)DateTime.Parse(raw, CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind),
+                _ => throw new CliFx.Exceptions.CommandException($"Unsupported DataType '{type}' for write."),
+            };
+        }
+        catch (FormatException ex)
+        {
+            throw new CliFx.Exceptions.CommandException(
+                $"Value '{raw}' is not a valid {type}: {ex.Message}");
+        }
+        catch (OverflowException ex)
+        {
+            throw new CliFx.Exceptions.CommandException(
+                $"Value '{raw}' is out of range for {type}: {ex.Message}");
+        }
+    }
 
     private static bool ParseBool(string raw) => raw.Trim().ToLowerInvariant() switch
     {
diff --git a/tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests/WriteCommandParseValueTests.cs b/tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests/WriteCommandParseValueTests.cs
index 904e060..ad99d7e 100644
--- a/tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests/WriteCommandParseValueTests.cs
+++ b/tests/Drivers/Cli/ZB.MOM.WW.OtOpcUa.Driver.S7.Cli.Tests/WriteCommandParseValueTests.cs
@@ -99,10 +99,20 @@ public sealed class WriteCommandParseValueTests
     [Fact]
     public void ParseValue_non_numeric_for_numeric_types_throws()
     {
-        Should.Throw<FormatException>(
+        // Driver.S7.Cli-001: malformed input must produce a clean CommandException
+        // (friendly one-line error), not a raw FormatException stack trace.
+        Should.Throw<CliFx.Exceptions.CommandException>(
             () => WriteCommand.ParseValue("xyz", S7DataType.Int16));
     }
 
+    [Fact]
+    public void ParseValue_overflow_for_numeric_types_throws_CommandException()
+    {
+        // OverflowException from out-of-range input must also surface as CommandException.
+        Should.Throw<CliFx.Exceptions.CommandException>(
+            () => WriteCommand.ParseValue("256", S7DataType.Byte));
+    }
+
     [Theory]
     [InlineData("DB1.DBW0", S7DataType.Int16, "DB1.DBW0:Int16")]
     [InlineData("M0.0", S7DataType.Bool, "M0.0:Bool")]