diff --git a/src/ZB.MOM.WW.ScadaBridge.DelmiaNotifier/ArgParser.cs b/src/ZB.MOM.WW.ScadaBridge.DelmiaNotifier/ArgParser.cs
new file mode 100644
index 00000000..e5d3ef72
--- /dev/null
+++ b/src/ZB.MOM.WW.ScadaBridge.DelmiaNotifier/ArgParser.cs
@@ -0,0 +1,73 @@
+namespace ZB.MOM.WW.ScadaBridge.DelmiaNotifier;
+
+/// <summary>Outcome of parsing the command line: success carries the payload, failure carries a human reason.</summary>
+internal sealed record ParseResult(bool Ok, RecipeDownload? Payload, string? Error)
+{
+    public static ParseResult Success(RecipeDownload payload) => new(true, payload, null);
+    public static ParseResult Fail(string error) => new(false, null, error);
+}
+
+/// <summary>
+/// Hand-rolled, reflection-free parser for the legacy WWNotifier flags. Each flag takes one value
+/// (short or long form). The four required flags must be present; the two optional flags may be omitted.
+/// </summary>
+internal static class ArgParser
+{
+    public static ParseResult Parse(string[] args)
+    {
+        var payload = new RecipeDownload();
+
+        for (var i = 0; i < args.Length; i++)
+        {
+            var flag = args[i];
+            if (i + 1 >= args.Length)
+            {
+                return ParseResult.Fail($"missing value for flag '{flag}'");
+            }
+
+            var value = args[++i];
+            switch (flag)
+            {
+                case "-m" or "--machine":
+                    payload.MachineCode = value;
+                    break;
+                case "-d" or "--downloadpath":
+                    payload.DownloadPath = value;
+                    break;
+                case "-w" or "--workorder":
+                    payload.WorkOrderNumber = value;
+                    break;
+                case "-p" or "--partnumber":
+                    payload.PartNumber = value;
+                    break;
+                case "-s" or "--seqop":
+                    payload.JobStepNumber = value;
+                    break;
+                case "-u" or "--username":
+                    payload.Username = value;
+                    break;
+                default:
+                    return ParseResult.Fail($"unknown flag '{flag}'");
+            }
+        }
+
+        if (string.IsNullOrEmpty(payload.MachineCode))
+        {
+            return ParseResult.Fail("missing required flag -m/--machine");
+        }
+        if (string.IsNullOrEmpty(payload.DownloadPath))
+        {
+            return ParseResult.Fail("missing required flag -d/--downloadpath");
+        }
+        if (string.IsNullOrEmpty(payload.WorkOrderNumber))
+        {
+            return ParseResult.Fail("missing required flag -w/--workorder");
+        }
+        if (string.IsNullOrEmpty(payload.PartNumber))
+        {
+            return ParseResult.Fail("missing required flag -p/--partnumber");
+        }
+
+        return ParseResult.Success(payload);
+    }
+}
diff --git a/tests/ZB.MOM.WW.ScadaBridge.DelmiaNotifier.Tests/ArgParserTests.cs b/tests/ZB.MOM.WW.ScadaBridge.DelmiaNotifier.Tests/ArgParserTests.cs
new file mode 100644
index 00000000..b0c45be8
--- /dev/null
+++ b/tests/ZB.MOM.WW.ScadaBridge.DelmiaNotifier.Tests/ArgParserTests.cs
@@ -0,0 +1,59 @@
+using ZB.MOM.WW.ScadaBridge.DelmiaNotifier;
+
+namespace ZB.MOM.WW.ScadaBridge.DelmiaNotifier.Tests;
+
+public class ArgParserTests
+{
+    [Fact]
+    public void Parses_all_flags()
+    {
+        var r = ArgParser.Parse(new[] { "-m", "Z28061", "-d", @"C:\r.nc", "-w", "W1", "-p", "P1", "-s", "0100", "-u", "op" });
+        Assert.True(r.Ok);
+        Assert.Equal("Z28061", r.Payload!.MachineCode);
+        Assert.Equal(@"C:\r.nc", r.Payload.DownloadPath);
+        Assert.Equal("W1", r.Payload.WorkOrderNumber);
+        Assert.Equal("P1", r.Payload.PartNumber);
+        Assert.Equal("0100", r.Payload.JobStepNumber);
+        Assert.Equal("op", r.Payload.Username);
+    }
+
+    [Fact]
+    public void Parses_long_flags()
+    {
+        var r = ArgParser.Parse(new[] { "--machine", "Z", "--downloadpath", "x", "--workorder", "W", "--partnumber", "P" });
+        Assert.True(r.Ok);
+        Assert.Equal("Z", r.Payload!.MachineCode);
+        Assert.Equal("x", r.Payload.DownloadPath);
+    }
+
+    [Fact]
+    public void Missing_required_returns_error()
+    {
+        var r = ArgParser.Parse(new[] { "-m", "Z28061", "-d", @"C:\r.nc", "-w", "W1" }); // no -p
+        Assert.False(r.Ok);
+        Assert.Contains("partnumber", r.Error, System.StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void Optional_flags_may_be_omitted()
+    {
+        var r = ArgParser.Parse(new[] { "-m", "Z", "-d", "x", "-w", "W", "-p", "P" });
+        Assert.True(r.Ok);
+        Assert.Null(r.Payload!.Username);
+        Assert.Null(r.Payload.JobStepNumber);
+    }
+
+    [Fact]
+    public void Unknown_flag_returns_error()
+    {
+        var r = ArgParser.Parse(new[] { "-z", "x" });
+        Assert.False(r.Ok);
+    }
+
+    [Fact]
+    public void Flag_without_value_returns_error()
+    {
+        var r = ArgParser.Parse(new[] { "-m" });
+        Assert.False(r.Ok);
+    }
+}