diff --git a/src/Clet/Hosting/CletExitCodes.cs b/src/Clet/Hosting/CletExitCodes.cs
new file mode 100644
index 0000000..8819af1
--- /dev/null
+++ b/src/Clet/Hosting/CletExitCodes.cs
@@ -0,0 +1,43 @@
+using System.Text.Json;
+using Terminal.Gui.Cli;
+
+namespace Clet;
+
+internal static class CletExitCodes
+{
+    public static int FromResult (CommandResult result)
+    {
+        if (result.Status == CommandStatus.Error && result.ErrorCode == "input-too-large")
+        {
+            return ExitCodes.ValidationError;
+        }
+
+        return ExitCodes.FromResult (result);
+    }
+
+    public static int MapPackageExit (int exitCode, string stdout)
+    {
+        if (exitCode == ExitCodes.UsageError && HasInputTooLargeCode (stdout))
+        {
+            return ExitCodes.ValidationError;
+        }
+
+        return exitCode;
+    }
+
+    private static bool HasInputTooLargeCode (string stdout)
+    {
+        try
+        {
+            using JsonDocument document = JsonDocument.Parse (stdout);
+
+            return document.RootElement.TryGetProperty ("code", out JsonElement code)
+                   && code.ValueKind == JsonValueKind.String
+                   && code.GetString () == "input-too-large";
+        }
+        catch (JsonException)
+        {
+            return false;
+        }
+    }
+}
diff --git a/src/Clet/Hosting/Program.cs b/src/Clet/Hosting/Program.cs
index 3bb4837..ef24443 100644
--- a/src/Clet/Hosting/Program.cs
+++ b/src/Clet/Hosting/Program.cs
@@ -7,25 +7,90 @@ internal static class Program
     public static async Task<int> Main (string[] args)
     {
         CletLogging.Initialize ();
+        CliHostOptions parserOptions = CreateOptions ();
 
-        CliHost host = new (options =>
-        {
-            options.ApplicationName = "clet";
-            options.Version = VersionInfo.GetCletVersion ();
-            options.HelpProvider = new CletHelpProvider ();
-            options.ResourceAssembly = typeof (Program).Assembly;
-
-            // clet-specific global options
-            options.GlobalOptions.Add (new GlobalOptionDescriptor ("allow-file", null,
-                "Explicitly allow reading a file path (bypasses extension + cwd checks).", false, Repeatable: true));
-            options.GlobalOptions.Add (new GlobalOptionDescriptor ("allow-binary", null,
-                "Permit binary file content (NUL bytes).", true));
-            options.GlobalOptions.Add (new GlobalOptionDescriptor ("no-browse", null,
-                "Disable browser-mode navigation for viewer clets.", true));
-        });
+        CliHost host = new (ConfigureOptions);
 
         BuiltInCommands.RegisterAll (host.Registry);
 
-        return await host.RunAsync (args);
+        if (TryHandleOversizedInitial (args, host.Registry, parserOptions, out int exitCode))
+        {
+            return exitCode;
+        }
+
+        using StringWriter stdout = new ();
+        using StringWriter stderr = new ();
+
+        int packageExitCode = await host.RunAsync (args, stdout: stdout, stderr: stderr);
+        string stdoutText = stdout.ToString ();
+        string stderrText = stderr.ToString ();
+
+        Console.Out.Write (stdoutText);
+        Console.Error.Write (stderrText);
+
+        return CletExitCodes.MapPackageExit (packageExitCode, stdoutText);
+    }
+
+    private static bool TryHandleOversizedInitial (
+        string[] args,
+        ICommandRegistry registry,
+        CliHostOptions options,
+        out int exitCode)
+    {
+        exitCode = ExitCodes.UsageError;
+        ArgParser parser = new (options.GlobalOptions, int.MaxValue);
+        ArgParser.ParseResult rootParse = parser.Parse (args);
+
+        if (!rootParse.Success
+            || rootParse.RootFlag is not null
+            || rootParse.Alias is null
+            || !registry.TryResolve (rootParse.Alias, out _))
+        {
+            return false;
+        }
+
+        CommandRunOptions? runOptions = rootParse.Options;
+
+        if (runOptions is null
+            || runOptions.Initial is null
+            || runOptions.Initial.Length <= options.MaxInitialChars)
+        {
+            return false;
+        }
+
+        CommandResult result = new (
+            CommandStatus.Error,
+            null,
+            "input-too-large",
+            $"--initial exceeds the maximum length of {options.MaxInitialChars} characters.");
+
+        ResultWriter.Write (result, runOptions.JsonOutput, Console.Out, Console.Error, runOptions.OutputPath);
+        exitCode = CletExitCodes.FromResult (result);
+
+        return true;
+    }
+
+    private static CliHostOptions CreateOptions ()
+    {
+        CliHostOptions options = new ();
+        ConfigureOptions (options);
+
+        return options;
+    }
+
+    private static void ConfigureOptions (CliHostOptions options)
+    {
+        options.ApplicationName = "clet";
+        options.Version = VersionInfo.GetCletVersion ();
+        options.HelpProvider = new CletHelpProvider ();
+        options.ResourceAssembly = typeof (Program).Assembly;
+
+        // clet-specific global options
+        options.GlobalOptions.Add (new GlobalOptionDescriptor ("allow-file", null,
+            "Explicitly allow reading a file path (bypasses extension + cwd checks).", false, Repeatable: true));
+        options.GlobalOptions.Add (new GlobalOptionDescriptor ("allow-binary", null,
+            "Permit binary file content (NUL bytes).", true));
+        options.GlobalOptions.Add (new GlobalOptionDescriptor ("no-browse", null,
+            "Disable browser-mode navigation for viewer clets.", true));
     }
 }
diff --git a/tests/Clet.SmokeTests/CletSmokeTests.cs b/tests/Clet.SmokeTests/CletSmokeTests.cs
index c3b689d..b46d6e7 100644
--- a/tests/Clet.SmokeTests/CletSmokeTests.cs
+++ b/tests/Clet.SmokeTests/CletSmokeTests.cs
@@ -111,7 +111,7 @@ public async Task MdOversizedStdin_ExitsWithError ()
         (int exit, string stdout, _) = await CletProcess.RunAsync (
             ["md", "--json"], stdin: oversized);
 
-        Assert.Equal (2, exit);
+        Assert.Equal (65, exit);
         Assert.Contains ("input-too-large", stdout);
         Assert.Contains ("\"status\":\"error\"", stdout);
     }
diff --git a/tests/Clet.UnitTests/ExitCodesTests.cs b/tests/Clet.UnitTests/ExitCodesTests.cs
index 280e377..99199d0 100644
--- a/tests/Clet.UnitTests/ExitCodesTests.cs
+++ b/tests/Clet.UnitTests/ExitCodesTests.cs
@@ -22,16 +22,13 @@ public void Constants_MatchSpec ()
     [InlineData ((int)CommandStatus.Cancelled, null, 130)]
     [InlineData ((int)CommandStatus.NoResult, null, 1)]
     [InlineData ((int)CommandStatus.Error, "validation", 65)]
-    // NOTE: spec requires input-too-large → 65, but the package maps all unknown error codes to 2.
-    // Tracked upstream: Terminal.Gui.Cli needs a custom exit code mapper or treating
-    // "input-too-large" as a validation error. See PR #185 review discussion.
-    [InlineData ((int)CommandStatus.Error, "input-too-large", 2)]
+    [InlineData ((int)CommandStatus.Error, "input-too-large", 65)]
     [InlineData ((int)CommandStatus.Error, "io", 74)]
     [InlineData ((int)CommandStatus.Error, "anything-else", 2)]
     public void FromResult_MapsStatusToExit (int statusInt, string? errorCode, int expected)
     {
         CommandResult result = new ((CommandStatus)statusInt, null, errorCode, null);
 
-        Assert.Equal (expected, ExitCodes.FromResult (result));
+        Assert.Equal (expected, CletExitCodes.FromResult (result));
     }
 }