VertexAI - Make SystemInstructions set a role (#1212)

Author: a-maurice

vertexai/src/Chat.cs

@@ -19,6 +19,7 @@
 using System.Collections.ObjectModel;
 using System.Linq;
 using System.Threading.Tasks;
+using Firebase.VertexAI.Internal;
 
 namespace Firebase.VertexAI {
 
@@ -123,26 +124,10 @@ public IAsyncEnumerable<GenerateContentResponse> SendMessageStreamAsync(
     return SendMessageStreamAsyncInternal(content);
   }
 
-  private ModelContent GuaranteeRole(ModelContent content, string role) {
-    if (content.Role == role) {
-      return content;
-    } else {
-      return new ModelContent(role, content.Parts);
-    }
-  }
-
-  private ModelContent GuaranteeUser(ModelContent content) {
-    return GuaranteeRole(content, "user");
-  }
-
-  private ModelContent GuaranteeModel(ModelContent content) {
-    return GuaranteeRole(content, "model");
-  }
-
   private async Task<GenerateContentResponse> SendMessageAsyncInternal(
       IEnumerable<ModelContent> requestContent) {
     // Make sure that the requests are set to to role "user".
-    List<ModelContent> fixedRequests = requestContent.Select(GuaranteeUser).ToList();
+    List<ModelContent> fixedRequests = requestContent.Select(VertexAIExtensions.ConvertToUser).ToList();
     // Set up the context to send in the request
     List<ModelContent> fullRequest = new(chatHistory);
     fullRequest.AddRange(fixedRequests);
@@ -157,7 +142,7 @@ private async Task<GenerateContentResponse> SendMessageAsyncInternal(
       ModelContent responseContent = response.Candidates.First().Content;
 
       chatHistory.AddRange(fixedRequests);
-      chatHistory.Add(GuaranteeModel(responseContent));
+      chatHistory.Add(responseContent.ConvertToModel());
     }
 
     return response;
@@ -166,7 +151,7 @@ private async Task<GenerateContentResponse> SendMessageAsyncInternal(
   private async IAsyncEnumerable<GenerateContentResponse> SendMessageStreamAsyncInternal(
       IEnumerable<ModelContent> requestContent) {
     // Make sure that the requests are set to to role "user".
-    List<ModelContent> fixedRequests = requestContent.Select(GuaranteeUser).ToList();
+    List<ModelContent> fixedRequests = requestContent.Select(VertexAIExtensions.ConvertToUser).ToList();
     // Set up the context to send in the request
     List<ModelContent> fullRequest = new(chatHistory);
     fullRequest.AddRange(fixedRequests);
@@ -181,7 +166,7 @@ private async IAsyncEnumerable<GenerateContentResponse> SendMessageStreamAsyncIn
       // but we don't want to save the history anymore.
       if (response.Candidates.Any()) {
         ModelContent responseContent = response.Candidates.First().Content;
-        responseContents.Add(GuaranteeModel(responseContent));
+        responseContents.Add(responseContent.ConvertToModel());
       } else {
         saveHistory = false;
       }

vertexai/src/GenerativeModel.cs

@@ -22,6 +22,7 @@
 using System.Text;
 using System.Threading.Tasks;
 using Google.MiniJSON;
+using Firebase.VertexAI.Internal;
 
 namespace Firebase.VertexAI {
 
@@ -66,7 +67,8 @@ internal GenerativeModel(FirebaseApp firebaseApp,
     _safetySettings = safetySettings;
     _tools = tools;
     _toolConfig = toolConfig;
-    _systemInstruction = systemInstruction;
+    // Make sure that the system instructions have the role "system".
+    _systemInstruction = systemInstruction?.ConvertToSystem();
     _requestOptions = requestOptions;
 
     // Create a HttpClient using the timeout requested, or the default one.

vertexai/src/Internal/InternalHelpers.cs

@@ -193,6 +193,26 @@ public static List<T> ConvertJsonList<T>(this List<object> list,
         .Select(converter)
         .ToList();
   }
+
+  public static ModelContent ConvertRole(this ModelContent content, string role) {
+    if (content.Role == role) {
+      return content;
+    } else {
+      return new ModelContent(role, content.Parts);
+    }
+  }
+
+  public static ModelContent ConvertToUser(this ModelContent content) {
+    return content.ConvertRole("user");
+  }
+
+  public static ModelContent ConvertToModel(this ModelContent content) {
+    return content.ConvertRole("model");
+  }
+
+  public static ModelContent ConvertToSystem(this ModelContent content) {
+    return content.ConvertRole("system");
+  }
 }
 
 }

vertexai/src/ModelContent.cs

@@ -55,17 +55,14 @@ public ModelContent(IEnumerable<Part> parts) : this("user", parts) { }
   /// <summary>
   /// Creates a `ModelContent` with the given role and `Part`s.
   /// </summary>
-  public ModelContent(string role, params Part[] parts) {
-    _role = role;
-    _parts = new ReadOnlyCollection<Part>(parts.ToList());
-  }
+  public ModelContent(string role, params Part[] parts) : this(role, (IEnumerable<Part>)parts) { }
 
   /// <summary>
   /// Creates a `ModelContent` with the given role and `Part`s.
   /// </summary>
   public ModelContent(string role, IEnumerable<Part> parts) {
     _role = role;
-    _parts = new ReadOnlyCollection<Part>(parts.ToList());
+    _parts = new ReadOnlyCollection<Part>(parts == null ? new List<Part>() : parts.ToList());
   }
 
 #region Helper Factories