Added the exact token count where the provider reports it (#989)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Provider/BaseProvider.cs

@@ -1118,6 +1118,21 @@ public abstract class BaseProvider : IProvider, ISecretId
                     continue;
                 }
 
+                //
+                // The line stating what the request cost carries no content of its own: providers
+                // send it as the last line of the stream, with no choices at all. It is handled
+                // before the check below, which would otherwise drop it as an empty response.
+                //
+                var usage = providerResponse.GetUsage();
+                if (usage.IsKnown)
+                {
+                    yield return providerResponse.ContainsContent()
+                        ? providerResponse.GetContent() with { Usage = usage }
+                        : new(string.Empty, [], Usage: usage);
+
+                    continue;
+                }
+
                 // Skip empty responses:
                 if (!providerResponse.ContainsContent())
                     continue;
@@ -1229,6 +1244,7 @@ public abstract class BaseProvider : IProvider, ISecretId
     /// <param name="systemPromptRole">The system prompt role to use.</param>
     /// <param name="requestPath">The request path, relative to the provider base URL.</param>
     /// <param name="headersAction">Optional additional headers to add.</param>
+    /// <param name="mayAskForSequentialToolCalls">Whether a request which offers tools may ask for one call at a time. False for a provider which rejects the parallel_tool_calls parameter.</param>
     /// <param name="token">The cancellation token.</param>
     /// <typeparam name="TRequest">The request DTO type.</typeparam>
     /// <typeparam name="TDelta">The delta stream line type.</typeparam>
@@ -1245,6 +1261,7 @@ public abstract class BaseProvider : IProvider, ISecretId
         string systemPromptRole = "system",
         string requestPath = "chat/completions",
         Action<HttpRequestHeaders>? headersAction = null,
+        bool mayAskForSequentialToolCalls = true,
         [EnumeratorCancellation] CancellationToken token = default)
         where TRequest : ChatCompletionAPIRequest
         where TDelta : IResponseStreamLine
@@ -1283,7 +1300,7 @@ public abstract class BaseProvider : IProvider, ISecretId
             if (runnableTools.Count > 0)
             {
                 var adapter = new ChatCompletionToolCallingAdapter<TRequest>(requestFactory, systemPrompt, apiParameters,
-                    runnableTools.Select(x => ProviderToolAdapters.ToChatCompletionTool(x.Definition)).ToList(), runnableTools,
+                    runnableTools.Select(x => ProviderToolAdapters.ToChatCompletionTool(x.Definition)).ToList(), mayAskForSequentialToolCalls, runnableTools,
                     (requestDto, requestToken) => this.StreamChatCompletionRequest(requestDto, providerName, requestPath, requestedSecret, headersAction, requestToken),
                     ChatCompletionSourceReader.Read<TDelta, TAnnotation>,
                     this.logger);