diff --git a/src/Plugins/BotSharp.Plugin.Membase/Interfaces/IMembaseApi.cs b/src/Plugins/BotSharp.Plugin.Membase/Interfaces/IMembaseApi.cs
index 8ab05160d..f8f5dcdc3 100644
--- a/src/Plugins/BotSharp.Plugin.Membase/Interfaces/IMembaseApi.cs
+++ b/src/Plugins/BotSharp.Plugin.Membase/Interfaces/IMembaseApi.cs
@@ -60,7 +60,7 @@ public interface IMembaseApi
     Task<PgtValidationResponse> ValidatePgtDefinitionAsync(string graphId, string definitionId, [Body] PgtValidationRequest request);
 
     [Post("/graph/{graphId}/pgt-external/{correlationId}/complete")]
-    Task<PgtExternalCompleteResponse> CompletePgtExternalAsync(string graphId, string correlationId, [FromBody] object emptyBody);
+    Task<PgtExternalCompleteResponse> CompletePgtExternalAsync(string graphId, string correlationId, [FromBody] object body);
     #endregion
 
     #region Procedure
diff --git a/src/Plugins/BotSharp.Plugin.Membase/MembasePlugin.cs b/src/Plugins/BotSharp.Plugin.Membase/MembasePlugin.cs
index dcd0ff091..69f47ae30 100644
--- a/src/Plugins/BotSharp.Plugin.Membase/MembasePlugin.cs
+++ b/src/Plugins/BotSharp.Plugin.Membase/MembasePlugin.cs
@@ -26,7 +26,11 @@ public void RegisterDI(IServiceCollection services, IConfiguration config)
 
         services.AddHttpContextAccessor();
         services.AddTransient<MembaseAuthHandler>();
-        services.AddRefitClient<IMembaseApi>(new RefitSettings
+        // Use plain Web options WITHOUT Refit's default ObjectToInferredTypesConverter:
+        // consumers (ObjectExtensions.TryGetValue<JsonElement>, GraphBuilder, GetNodePropertiesOrDefault)
+        // rely on Dictionary<string, object?> values deserializing as JsonElement.
+        services.AddRefitClient<IMembaseApi>(new RefitSettings(
+                new SystemTextJsonContentSerializer(new JsonSerializerOptions(JsonSerializerDefaults.Web)))
                 {
                     CollectionFormat = CollectionFormat.Multi
                 })
diff --git a/src/Plugins/BotSharp.Plugin.OpenAI/Providers/ProviderHelper.cs b/src/Plugins/BotSharp.Plugin.OpenAI/Providers/ProviderHelper.cs
index df937390d..121b7a6d5 100644
--- a/src/Plugins/BotSharp.Plugin.OpenAI/Providers/ProviderHelper.cs
+++ b/src/Plugins/BotSharp.Plugin.OpenAI/Providers/ProviderHelper.cs
@@ -9,6 +9,10 @@ public static OpenAIClient GetClient(string provider, string model, string? apiK
     {
         var settingsService = services.GetRequiredService<ILlmProviderService>();
         var settings = settingsService.GetSetting(provider, model);
+        if (settings == null && string.IsNullOrEmpty(apiKey))
+        {
+            throw new InvalidOperationException($"No LLM model settings found for '{provider}.{model}'. Register the model under LlmProviders (appsettings/user secrets) or pass an api key.");
+        }
         var options = !string.IsNullOrEmpty(settings?.Endpoint) ?
                         new OpenAIClientOptions { Endpoint = new Uri(settings.Endpoint) } : null;
         return new OpenAIClient(new ApiKeyCredential(apiKey ?? settings!.ApiKey), options);