optimize PushIndication

src/Infrastructure/BotSharp.Core/Demo/Functions/GetFunEventsFn.cs

@@ -18,28 +18,14 @@ public GetFunEventsFn(IServiceProvider services)
     public async Task<bool> Execute(RoleDialogModel message)
     {
         var args = JsonSerializer.Deserialize<WeatherLocation>(message.FunctionArgs);
-        var conv = _services.GetRequiredService<IConversationService>();
-        var messageHub = _services.GetRequiredService<MessageHub<HubObserveData<RoleDialogModel>>>();
 
         await Task.Delay(1000);
 
-        message.Indication = $"Start querying event data in {args?.City}";
-        messageHub.Push(new()
-        {
-            EventName = ChatEvent.OnIndicationReceived,
-            Data = message,
-            RefId = conv.ConversationId
-        });
+        _services.GetHub().PushIndication(message, $"Start querying event data in {args?.City}");
 
         await Task.Delay(1500);
 
-        message.Indication = $"Still searching events in {args?.City}";
-        messageHub.Push(new()
-        {
-            EventName = ChatEvent.OnIndicationReceived,
-            Data = message,
-            RefId = conv.ConversationId
-        });
+        _services.GetHub().PushIndication(message, $"Still searching events in {args?.City}");
 
         await Task.Delay(1500);
 

src/Infrastructure/BotSharp.Core/Demo/Functions/GetWeatherFn.cs

@@ -28,13 +28,7 @@ public async Task<bool> Execute(RoleDialogModel message)
 
         await Task.Delay(1000);
 
-        message.Indication = $"Start querying weather data in {args?.City}";
-        messageHub.Push(new()
-        {
-            EventName = ChatEvent.OnIndicationReceived,
-            Data = message,
-            RefId = conv.ConversationId
-        });
+        _services.GetHub().PushIndication(message, $"Start querying weather data in {args?.City}");
 
         await Task.Delay(1500);
 
@@ -49,13 +43,7 @@ public async Task<bool> Execute(RoleDialogModel message)
         });
 #endif
 
-        message.Indication = $"Still working on it... Hold on, {args?.City}";
-        messageHub.Push(new()
-        {
-            EventName = ChatEvent.OnIndicationReceived,
-            Data = message,
-            RefId = conv.ConversationId
-        });
+        _services.GetHub().PushIndication(message, $"Still working on it... Hold on, {args?.City}");
 
         await Task.Delay(1500);
 

src/Infrastructure/BotSharp.Core/MessageHub/ConversationHub.cs

@@ -0,0 +1,42 @@
+namespace BotSharp.Core.MessageHub;
+
+/// <summary>
+/// Pushing events into one conversation. The id is captured when the hub is taken, on the thread
+/// that asked for it -- a reporter running on a transport's own thread can keep this and push
+/// without resolving a scoped service again. Don't hold one past the conversation it was taken for.
+/// </summary>
+public sealed class ConversationHub
+{
+    private readonly MessageHub<HubObserveData<RoleDialogModel>> _hub;
+
+    internal ConversationHub(MessageHub<HubObserveData<RoleDialogModel>> hub, string? conversationId)
+    {
+        _hub = hub;
+        ConversationId = conversationId;
+    }
+
+    /// <summary>Where every push goes; null when taken outside a conversation.</summary>
+    public string? ConversationId { get; }
+
+    /// <summary>
+    /// Raise the "working on it" line in chat. <paramref name="message"/> is pushed as-is and its
+    /// <c>Indication</c> overwritten, so clone it when the original is still in use by a call in flight.
+    /// </summary>
+    public void PushIndication(RoleDialogModel message, string? indication)
+    {
+        // Nothing to announce, or no one to announce it to: subscribers match on RefId.
+        if (string.IsNullOrWhiteSpace(indication) || string.IsNullOrWhiteSpace(ConversationId))
+        {
+            return;
+        }
+
+        message.Indication = indication;
+
+        _hub.Push(new()
+        {
+            EventName = ChatEvent.OnIndicationReceived,
+            Data = message,
+            RefId = ConversationId
+        });
+    }
+}

src/Infrastructure/BotSharp.Core/MessageHub/MessageHubExtensions.cs

@@ -0,0 +1,14 @@
+namespace BotSharp.Core.MessageHub;
+
+public static class MessageHubExtensions
+{
+    /// <summary>
+    /// The hub bound to the conversation this call is running in.
+    /// </summary>
+    public static ConversationHub GetHub(this IServiceProvider services)
+    {
+        var conv = services.GetRequiredService<IConversationService>();
+        var hub = services.GetRequiredService<MessageHub<HubObserveData<RoleDialogModel>>>();
+        return new ConversationHub(hub, conv.ConversationId);
+    }
+}

src/Infrastructure/BotSharp.Core/Routing/Executor/MCPToolExecutor.cs

@@ -87,17 +87,12 @@ public Task<string> GetIndicatorAsync(RoleDialogModel message)
     /// </summary>
     private sealed class ToolProgressIndicator : IProgress<ProgressNotificationValue>
     {
-        private readonly MessageHub<HubObserveData<RoleDialogModel>> _hub;
-        private readonly string _conversationId;
+        private readonly ConversationHub _hub;
         private readonly RoleDialogModel _message;
 
-        private ToolProgressIndicator(
-            MessageHub<HubObserveData<RoleDialogModel>> hub,
-            string conversationId,
-            RoleDialogModel message)
+        private ToolProgressIndicator(ConversationHub hub, RoleDialogModel message)
         {
             _hub = hub;
-            _conversationId = conversationId;
             _message = message;
         }
 
@@ -106,22 +101,16 @@ private ToolProgressIndicator(
         /// tool invoked outside one, from a task or a test. Null is the right answer there rather
         /// than a reporter that drops everything: it also tells the server not to bother sending.
         /// <para>
-        /// The conversation id is read HERE, on the thread that starts the call, and captured.
-        /// <see cref="Report"/> runs on whichever thread the MCP transport is reading on, and
-        /// resolving a scoped service from there to ask again would be a race for a value that
+        /// The hub is taken HERE, on the thread that starts the call, so it carries the conversation
+        /// id with it. <see cref="Report"/> runs on whichever thread the MCP transport is reading on,
+        /// and resolving a scoped service from there to ask again would be a race for a value that
         /// cannot change during the call.
         /// </para>
         /// </summary>
         public static ToolProgressIndicator? For(IServiceProvider services, RoleDialogModel message)
         {
-            var conversationId = services.GetRequiredService<IConversationService>().ConversationId;
-            if (string.IsNullOrWhiteSpace(conversationId))
-            {
-                return null;
-            }
-
-            var hub = services.GetRequiredService<MessageHub<HubObserveData<RoleDialogModel>>>();
-            return new ToolProgressIndicator(hub, conversationId, message);
+            var hub = services.GetHub();
+            return string.IsNullOrWhiteSpace(hub.ConversationId) ? null : new ToolProgressIndicator(hub, message);
         }
 
         /// <summary>
@@ -145,15 +134,7 @@ public void Report(ProgressNotificationValue value)
 
             // Cloned: this is pushed to observers that read it, and the function's own message is
             // still being used by the call in flight. Its indication is not ours to overwrite.
-            var indication = RoleDialogModel.From(_message);
-            indication.Indication = value.Message;
-
-            _hub.Push(new()
-            {
-                EventName = ChatEvent.OnIndicationReceived,
-                Data = indication,
-                RefId = _conversationId
-            });
+            _hub.PushIndication(RoleDialogModel.From(_message), value.Message);
         }
     }
 

src/Infrastructure/BotSharp.Core/Routing/RoutingService.InvokeFunction.cs

@@ -26,20 +26,10 @@ public async Task<bool> InvokeFunction(string name, RoleDialogModel message, Inv
         // Clone message
         var clonedMessage = RoleDialogModel.From(message);
         clonedMessage.FunctionName = name;
+        // Assigned even when empty: the hooks below log this field, and the value From() copied
+        // would otherwise linger there.
         clonedMessage.Indication = await funcExecutor.GetIndicatorAsync(message);
-
-        // An empty indicator means the callee has nothing worth announcing for this call.
-        if (!string.IsNullOrEmpty(clonedMessage.Indication))
-        {
-            var conv = _services.GetRequiredService<IConversationService>();
-            var messageHub = _services.GetRequiredService<MessageHub<HubObserveData<RoleDialogModel>>>();
-            messageHub.Push(new()
-            {
-                EventName = ChatEvent.OnIndicationReceived,
-                Data = clonedMessage,
-                RefId = conv.ConversationId
-            });
-        }
+        _services.GetHub().PushIndication(clonedMessage, clonedMessage.Indication);
 
         var hooks = _services.GetHooksOrderByPriority<IConversationHook>(clonedMessage.CurrentAgentId);
         foreach (var hook in hooks)