Stream the answers again whenever tools are in play (#986)

app/MindWork AI Studio/Provider/Anthropic/AnthropicToolCallingAdapter.cs

@@ -1,3 +1,5 @@
+using System.Runtime.CompilerServices;
+
 using AIStudio.Tools.ToolCallingSystem;
 using AIStudio.Tools.ToolCallingSystem.Harness;
 
@@ -15,7 +17,7 @@ namespace AIStudio.Provider.Anthropic;
 /// </remarks>
 public sealed class AnthropicToolCallingAdapter(Model chatModel, IList<IMessageBase> baseMessages, string systemPrompt, int maxTokens,
     IDictionary<string, object> apiParameters, IReadOnlyList<(ToolDefinition Definition, IToolImplementation Implementation)> runnableTools,
-    Func<ChatRequest, CancellationToken, Task<AnthropicResponse?>> executeRequestAsync) : IToolCallingProviderAdapter
+    Func<ChatRequest, CancellationToken, IAsyncEnumerable<ServerSentEvent>> streamRequestAsync) : IToolCallingProviderAdapter
 {
     private readonly List<IMessageBase> internalMessages = [];
     private readonly List<AnthropicToolResultContent> pendingToolResults = [];
@@ -27,7 +29,7 @@ public sealed class AnthropicToolCallingAdapter(Model chatModel, IList<IMessageB
     public IReadOnlyList<string> RecordedRequestTexts => this.recordedRequestTexts;
 
     /// <inheritdoc />
-    public async Task<ToolCallingRound?> ExecuteRoundAsync(string? finalResponseInstruction, bool includeTools, CancellationToken token = default)
+    public async IAsyncEnumerable<ToolCallingStreamEvent> ExecuteRoundAsync(string? finalResponseInstruction, bool includeTools, [EnumeratorCancellation] CancellationToken token = default)
     {
         //
         // The results of the previous round are flushed here rather than when they were recorded:
@@ -39,7 +41,7 @@ public sealed class AnthropicToolCallingAdapter(Model chatModel, IList<IMessageB
             this.pendingToolResults.Clear();
         }
 
-        var response = await executeRequestAsync(new ChatRequest
+        var request = new ChatRequest
         {
             Model = chatModel.Id,
             Messages = [..baseMessages, ..this.internalMessages],
@@ -48,16 +50,29 @@ public sealed class AnthropicToolCallingAdapter(Model chatModel, IList<IMessageB
                 : $"{systemPrompt}{Environment.NewLine}{Environment.NewLine}{finalResponseInstruction}",
 
             MaxTokens = maxTokens,
-            Stream = false,
+            Stream = true,
             Tools = includeTools && this.tools.Count > 0 ? this.tools : null,
             AdditionalApiParameters = apiParameters,
-        }, token);
+        };
 
+        //
+        // The text goes out while it is being written; the blocks are put back together behind
+        // it, because they have to return to the provider exactly as they arrived.
+        //
+        var accumulator = new AnthropicMessageStreamAccumulator();
+        await foreach (var serverSentEvent in streamRequestAsync(request, token))
+        {
+            var part = accumulator.Process(serverSentEvent);
+            if (part.HasContent)
+                yield return ToolCallingStreamEvent.TextDelta(part.TextDelta);
+        }
+
+        var response = accumulator.Build();
         if (response is null)
-            return null;
+            yield break;
 
         this.lastResponse = response;
-        return new ToolCallingRound(
+        yield return ToolCallingStreamEvent.RoundCompleted(new ToolCallingRound(
             response.GetTextOutput(),
             response.GetToolUses()
                 .Select(toolUse => new ToolCallingRequestedCall(
@@ -66,7 +81,7 @@ public sealed class AnthropicToolCallingAdapter(Model chatModel, IList<IMessageB
                     toolUse.Arguments,
                     ToolExecutor.IsValidArgumentsJson(toolUse.Arguments)))
                 .ToList(),
-            []);
+            []));
     }
 
     /// <inheritdoc />