Complete runtime diagnostics and verification coverage

1 files changed, 26 insertions, 2 deletions

diff --git a/src/Agent.App/Program.cs b/src/Agent.App/Program.cs
index 6f3485f..3d2d2db 100644
--- a/src/Agent.App/Program.cs
+++ b/src/Agent.App/Program.cs
@@ -110,7 +110,7 @@ internal static class Program
         }
         catch (Exception ex) when (ex is CommandLineException or ConfigurationException or LocaleException or IOException or UnauthorizedAccessException)
         {
-            Console.Error.WriteLine($"agent-mcp: {ex.Message}");
+            Console.Error.WriteLine($"agent-mcp: {FormatStartupError(args, ex)}");
             return 2;
         }
         catch (Exception ex) when (ex is not (OutOfMemoryException or StackOverflowException or AccessViolationException))
@@ -120,6 +120,30 @@ internal static class Program
         }
     }
 
+    internal static string FormatStartupError(string[] args, Exception error)
+    {
+        string language = "en";
+        for (int i = 0; i + 1 < args.Length; i++)
+            if (args[i] == "--lang") language = args[i + 1];
+        try
+        {
+            string directory = Path.Combine(AppContext.BaseDirectory, "config", "locales");
+            LocaleCatalog locale = LocaleCatalog.Load(directory, language, "en");
+            string key = error switch
+            {
+                CommandLineException => "cli.invalid",
+                ConfigurationException => "config.invalid",
+                LocaleException => "locale.invalid",
+                _ => "app.io_error"
+            };
+            return locale.Format(key, new Dictionary<string, object?> { ["message"] = error.Message });
+        }
+        catch
+        {
+            return error.Message;
+        }
+    }
+
     private static InternalToolDispatcher CreateToolDispatcher(AgentConfiguration configuration, string baseDirectory, string logDirectory, SessionStore? sessionStore = null)
     {
         string stateDirectory = Path.Combine(baseDirectory, "state");
@@ -155,7 +179,7 @@ internal static class Program
         }
     }
 
-    private static AgentRuntimeSettings CreateRuntimeSettings(AgentConfiguration configuration, string userPrompt, string language,
+    internal static AgentRuntimeSettings CreateRuntimeSettings(AgentConfiguration configuration, string userPrompt, string language,
         IReadOnlyList<Agent.Core.Skills.AgentSkill> skills, LocaleCatalog locale) => new(
         userPrompt,
         language,