diff --git a/src/Chip8.Cli/AsmCommand.cs b/src/Chip8.Cli/AsmCommand.cs
new file mode 100644
index 0000000..0ac103a
--- /dev/null
+++ b/src/Chip8.Cli/AsmCommand.cs
@@ -0,0 +1,68 @@
+using System;
+using System.IO;
+using Chip8.Core;
+using Chip8.Core.Assembly;
+
+namespace Chip8.Cli;
+
+static class AsmCommand
+{
+    public static int run(string[] args)
+    {
+        if (args.Length < 1)
+        {
+            Console.Error.WriteLine("usage: chip8 asm <source.asm> [-o out.ch8] [--listing]");
+            return 1;
+        }
+
+        string sourcePath = args[0];
+        string? outputPath = null;
+        bool showListing = false;
+
+        for (int index = 1; index < args.Length; index++)
+        {
+            switch (args[index])
+            {
+                case "-o":
+                case "--out":
+                    outputPath = args[++index];
+                    break;
+                case "--listing":
+                    showListing = true;
+                    break;
+                default:
+                    Console.Error.WriteLine($"error: unknown asm option {args[index]}");
+                    return 1;
+            }
+        }
+
+        if (!File.Exists(sourcePath))
+        {
+            Console.Error.WriteLine($"error: source not found: {sourcePath}");
+            return 1;
+        }
+
+        string source = File.ReadAllText(sourcePath);
+        AssemblyResult result;
+        try
+        {
+            result = new Assembler().assemble(source);
+        }
+        catch (AsmException error)
+        {
+            Console.Error.WriteLine($"error: {error.Message}");
+            return 1;
+        }
+
+        outputPath ??= Path.ChangeExtension(sourcePath, ".ch8");
+        File.WriteAllBytes(outputPath, result.rom);
+        Console.WriteLine($"assembled {result.rom.Length} bytes -> {outputPath}");
+
+        if (showListing)
+        {
+            Console.Write(result.listing);
+        }
+
+        return 0;
+    }
+}
diff --git a/src/Chip8.Cli/DisasmCommand.cs b/src/Chip8.Cli/DisasmCommand.cs
new file mode 100644
index 0000000..b56cd08
--- /dev/null
+++ b/src/Chip8.Cli/DisasmCommand.cs
@@ -0,0 +1,46 @@
+using System;
+using System.Globalization;
+using System.IO;
+using Chip8.Core;
+
+namespace Chip8.Cli;
+
+static class DisasmCommand
+{
+    public static int run(string[] args)
+    {
+        if (args.Length < 1)
+        {
+            Console.Error.WriteLine("usage: chip8 disasm <rom.ch8> [--base 0x200]");
+            return 1;
+        }
+
+        string romPath = args[0];
+        ushort baseAddress = Machine.programStart;
+
+        for (int index = 1; index < args.Length; index++)
+        {
+            if (args[index] == "--base")
+            {
+                string value = args[++index];
+                string digits = value.StartsWith("0x", StringComparison.OrdinalIgnoreCase) ? value.Substring(2) : value;
+                baseAddress = ushort.Parse(digits, NumberStyles.HexNumber, CultureInfo.InvariantCulture);
+            }
+            else
+            {
+                Console.Error.WriteLine($"error: unknown disasm option {args[index]}");
+                return 1;
+            }
+        }
+
+        if (!File.Exists(romPath))
+        {
+            Console.Error.WriteLine($"error: ROM not found: {romPath}");
+            return 1;
+        }
+
+        byte[] rom = File.ReadAllBytes(romPath);
+        Console.Write(Disassembler.render(rom, baseAddress));
+        return 0;
+    }
+}
diff --git a/src/Chip8.Cli/TuiDebugger.cs b/src/Chip8.Cli/TuiDebugger.cs
new file mode 100644
index 0000000..8257177
--- /dev/null
+++ b/src/Chip8.Cli/TuiDebugger.cs
@@ -0,0 +1,65 @@
+using System;
+using System.IO;
+using Chip8.Core;
+
+namespace Chip8.Cli;
+
+static class TuiDebugger
+{
+    public static int run(string[] args)
+    {
+        if (args.Length < 1)
+        {
+            Console.Error.WriteLine("usage: chip8 debug <rom.ch8> [--platform NAME]");
+            return 1;
+        }
+
+        var forwarded = new string[args.Length];
+        forwarded[0] = args[0];
+        Array.Copy(args, 1, forwarded, 1, args.Length - 1);
+
+        Options options;
+        try
+        {
+            options = Options.parse(forwarded);
+        }
+        catch (ArgumentException error)
+        {
+            Console.Error.WriteLine($"error: {error.Message}");
+            return 1;
+        }
+
+        if (!File.Exists(options.romPath))
+        {
+            Console.Error.WriteLine($"error: ROM not found: {options.romPath}");
+            return 1;
+        }
+
+        var machine = new Machine(options.buildQuirks(), options.seed, options.buildPlatform());
+        machine.loadRom(File.ReadAllBytes(options.romPath));
+
+        var console = new DebuggerConsole(new Debugger(machine));
+        Console.WriteLine($"chip8-sharp debugger - {Path.GetFileName(options.romPath)} ({options.buildPlatform()})");
+        Console.WriteLine("type 'help' for commands");
+        Console.Write(console.execute("dis 5"));
+        Console.WriteLine();
+
+        while (!console.quitRequested)
+        {
+            Console.Write("(chip8) ");
+            string? line = Console.ReadLine();
+            if (line is null)
+            {
+                break;
+            }
+
+            string output = console.execute(line);
+            if (output.Length > 0)
+            {
+                Console.WriteLine(output);
+            }
+        }
+
+        return 0;
+    }
+}