Kept the reported token usage as one record on the answer

app/MindWork AI Studio/Chat/ContentText.cs

@@ -62,38 +62,8 @@ public sealed class ContentText : IContent
     /// falls back to the estimate instead of carrying a figure for a conversation which no longer
     /// exists. Null for every answer written before this was recorded, and at every provider which
     /// reports nothing.
-    ///
-    /// Two plain numbers rather than a TokenUsage: that type only ever comes out of its own
-    /// factory, which is what keeps an impossible usage from existing, and a stored field has to be
-    /// readable back by the serializer.
     /// </remarks>
-    public int? ReportedPromptTokens { get; set; }
+    public ReportedTokenUsage? ReportedUsage { get; set; }
-
-    /// <summary>
-    /// What the provider said the answer itself cost, where it said anything.
-    /// </summary>
-    /// <remarks>
-    /// Stored, kept, and dropped together with ReportedPromptTokens, for the reasons given there.
-    /// </remarks>
-    public int? ReportedCompletionTokens { get; set; }
-
-    /// <summary>
-    /// Which model the numbers above were charged for.
-    /// </summary>
-    /// <remarks>
-    /// A token count belongs to the tokenizer which produced it. Switch the model of a chat, and
-    /// the same conversation is worth a different number of tokens -- so the reported one stops
-    /// being an answer about the request which is about to be sent, and the estimate, wrong as it
-    /// is, is at least wrong about the right model.
-    /// </remarks>
-    public string? ReportedForModel { get; set; }
-
-    /// <summary>
-    /// What the provider said this exchange cost, which is what the next request carries as its
-    /// history.
-    /// </summary>
-    [JsonIgnore]
-    public TokenUsage ReportedTokens => TokenUsage.OfReported(this.ReportedPromptTokens, this.ReportedCompletionTokens);
 
     [JsonIgnore]
     public ToolRuntimeStatus ToolRuntimeStatus { get; set; } = new();
@@ -141,6 +111,29 @@ public sealed class ContentText : IContent
     /// </remarks>
     public void EndToolRun() => this.PendingToolConversation = [];
 
+    /// <summary>
+    /// Keeps what the provider says the request behind this answer cost.
+    /// </summary>
+    /// <remarks>
+    /// The one place where a stream's usage becomes part of the answer, for every path which writes
+    /// one. It arrives on one line of the stream, usually the last one, and only where the provider
+    /// reports it at all -- so a usage which states nothing leaves what was reported before alone.
+    /// </remarks>
+    /// <param name="usage">What the current chunk of the stream says, which is mostly nothing.</param>
+    /// <param name="modelId">The model the request went to.</param>
+    public void RecordReportedUsage(TokenUsage usage, string modelId)
+    {
+        if (!usage.IsKnown)
+            return;
+
+        this.ReportedUsage = new()
+        {
+            PromptTokens = usage.PromptTokens,
+            CompletionTokens = usage.CompletionTokens,
+            ModelId = modelId,
+        };
+    }
+
     /// <inheritdoc />
     public async Task<ChatThread> CreateFromProviderAsync(IProvider provider, Model chatModel, IContent? lastUserPrompt, ChatThread? chatThread, CancellationToken token = default)
     {
@@ -230,17 +223,8 @@ public sealed class ContentText : IContent
                         // Merge the sources:
                         this.Sources.MergeSources(contentStreamChunk.Sources);
 
-                        //
+                        // Keep what the provider says the request cost:
-                        // Keep what the provider says the request cost. It arrives on one line of
+                        this.RecordReportedUsage(contentStreamChunk.Usage, chatModel.Id);
-                        // the stream, usually the last one, and only where the provider reports it
-                        // at all -- so the previous value is kept rather than cleared:
-                        //
-                        if (contentStreamChunk.Usage.IsKnown)
-                        {
-                            this.ReportedPromptTokens = contentStreamChunk.Usage.PromptTokens;
-                            this.ReportedCompletionTokens = contentStreamChunk.Usage.CompletionTokens;
-                            this.ReportedForModel = chatModel.Id;
-                        }
 
                         // Notify the UI that the content has changed,
                         // depending on the energy saving mode:

app/MindWork AI Studio/Chat/ReportedTokenUsage.cs

@@ -0,0 +1,45 @@
+using AIStudio.Provider;
+
+namespace AIStudio.Chat;
+
+/// <summary>
+/// What a provider said the request behind one answer cost, as it is stored on that answer.
+/// </summary>
+/// <remarks>
+/// The numbers and the model they were charged for travel as one value. Each of them is meaningless
+/// without the others, and loose fields on the answer could be set, cleared, or copied apart.
+///
+/// Plain numbers rather than a TokenUsage: that type only ever comes out of its own factory, which
+/// is what keeps an impossible usage from existing, while a stored value has to be readable back by
+/// the serializer. ToTokenUsage is the way back, and it treats a chat file somebody edited by hand
+/// the same way the reading side treats a provider's JSON.
+/// </remarks>
+public sealed record ReportedTokenUsage
+{
+    /// <summary>
+    /// What everything sent to the model cost.
+    /// </summary>
+    public int PromptTokens { get; init; }
+
+    /// <summary>
+    /// What the model wrote in answer.
+    /// </summary>
+    public int CompletionTokens { get; init; }
+
+    /// <summary>
+    /// Which model the numbers were charged for.
+    /// </summary>
+    /// <remarks>
+    /// A token count belongs to the tokenizer which produced it. Switch the model of a chat, and
+    /// the same conversation is worth a different number of tokens -- so the reported one stops
+    /// being an answer about the request which is about to be sent, and the estimate, wrong as it
+    /// is, is at least wrong about the right model.
+    /// </remarks>
+    public string ModelId { get; init; } = string.Empty;
+
+    /// <summary>
+    /// States the stored numbers as a usage again.
+    /// </summary>
+    /// <returns>The usage, or TokenUsage.UNKNOWN when the stored numbers state nothing usable.</returns>
+    public TokenUsage ToTokenUsage() => TokenUsage.OfReported(this.PromptTokens, this.CompletionTokens);
+}

app/MindWork AI Studio/Components/ChatComponent.razor.cs

@@ -1650,10 +1650,11 @@ public partial class ChatComponent : MSGComponentBase
     {
         for (var index = thread.Blocks.Count - 1; index >= 0; index--)
         {
-            if (thread.Blocks[index].Content is not ContentText { IsStreaming: false } text)
+            if (thread.Blocks[index].Content is not ContentText { IsStreaming: false, ReportedUsage: { } reported })
                 continue;
 
-            if (!text.ReportedTokens.IsKnown)
+            var usage = reported.ToTokenUsage();
+            if (!usage.IsKnown)
                 continue;
 
             //
@@ -1662,8 +1663,8 @@ public partial class ChatComponent : MSGComponentBase
             // answers of that same other model, so the search ends here and the estimate takes
             // over until this model has answered once.
             //
-            return string.Equals(text.ReportedForModel, model.Id, StringComparison.Ordinal)
+            return string.Equals(reported.ModelId, model.Id, StringComparison.Ordinal)
-                ? text.ReportedTokens
+                ? usage
                 : TokenUsage.UNKNOWN;
         }
 

app/MindWork AI Studio/Tools/AIJobs/AIJobService.cs

@@ -455,18 +455,7 @@ public sealed class AIJobService(SettingsManager settingsManager, MessageBus mes
             aiText.IsStreaming = true;
             aiText.Text += contentStreamChunk;
             aiText.Sources.MergeSources(contentStreamChunk.Sources);
-
+            aiText.RecordReportedUsage(contentStreamChunk.Usage, state.ChatGenerationRequest.ProviderSettings.Model.Id);
-            //
-            // Keep what the provider says the request cost. It arrives on one line of the stream,
-            // usually the last one, and only where a provider reports it at all -- so a chunk
-            // without it leaves what was reported before alone.
-            //
-            if (contentStreamChunk.Usage.IsKnown)
-            {
-                aiText.ReportedPromptTokens = contentStreamChunk.Usage.PromptTokens;
-                aiText.ReportedCompletionTokens = contentStreamChunk.Usage.CompletionTokens;
-                aiText.ReportedForModel = state.ChatGenerationRequest.ProviderSettings.Model.Id;
-            }
 
             if (state.Snapshot.Status is not AIJobStatus.RUNNING)
             {