From 9c4fcb18e33d5efcc8469425b40255d7085e2068 Mon Sep 17 00:00:00 2001
From: Jicheng Lu <103353@smsassist.com>
Date: Tue, 18 Aug 2026 10:31:06 -0500
Subject: [PATCH] fix inbound translation

---
 .../Routing/RoutingService.InstructLoop.cs    | 15 +-----
 .../Routing/RoutingService.Translation.cs     | 53 +++++++++++++++++++
 .../BotSharp.Core/Routing/RoutingService.cs   |  5 ++
 3 files changed, 59 insertions(+), 14 deletions(-)
 create mode 100644 src/Infrastructure/BotSharp.Core/Routing/RoutingService.Translation.cs

diff --git a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InstructLoop.cs b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InstructLoop.cs
index 9fff55c92..63d588a45 100644
--- a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InstructLoop.cs
+++ b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.InstructLoop.cs
@@ -24,20 +24,7 @@ public async Task<RoleDialogModel> InstructLoop(Agent agent, RoleDialogModel mes
         await _context.Push(_router.Id);
 
         // Handle multi-language for input
-        var agentSettings = _services.GetRequiredService<AgentSettings>();
-        if (agentSettings.EnableTranslator)
-        {
-            var translator = _services.GetRequiredService<ITranslationService>();
-
-            var language = states.GetState(StateConst.LANGUAGE, LanguageType.ENGLISH);
-            if (language != LanguageType.ENGLISH)
-            {
-                message.SecondaryContent = message.Content;
-                message.Content = await translator.Translate(_router, message.MessageId, message.Content,
-                    language: LanguageType.ENGLISH,
-                    clone: false);
-            }
-        }
+        await TranslateInboundMessage(_router, message);
 
         dialogs.Add(message);
         Context.SetDialogs(dialogs);
diff --git a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.Translation.cs b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.Translation.cs
new file mode 100644
index 000000000..8aa297d3f
--- /dev/null
+++ b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.Translation.cs
@@ -0,0 +1,53 @@
+using BotSharp.Abstraction.Infrastructures.Enums;
+
+namespace BotSharp.Core.Routing;
+
+public partial class RoutingService
+{
+    private const string TranslationPromptName = "translation_prompt";
+
+    /// <summary>
+    /// Normalize an inbound user message to English so routing rules, agent instructions and
+    /// function arguments are always evaluated in English. The user's original text is kept in
+    /// SecondaryContent. Shared by InstructLoop and InstructDirect so every entry point into the
+    /// routing service behaves the same way.
+    /// </summary>
+    private async Task TranslateInboundMessage(Agent agent, RoleDialogModel message)
+    {
+        var agentSettings = _services.GetRequiredService<AgentSettings>();
+        if (!agentSettings.EnableTranslator)
+        {
+            return;
+        }
+
+        var states = _services.GetRequiredService<IConversationStateService>();
+
+        // The caller supplies the language through the request states; the server does not detect it.
+        // TranslationService back-fills StateConst.LANGUAGE only when the state is absent, which cannot
+        // happen here - an absent state defaults to English and returns early. That back-fill serves
+        // the /translate endpoint instead.
+        // Unknown is excluded to stay in sync with TranslationResponseHook: it means the language has
+        // not been resolved, so translating would only paraphrase the user's own words.
+        var language = states.GetState(StateConst.LANGUAGE, LanguageType.ENGLISH);
+        if (language == LanguageType.ENGLISH || language == LanguageType.UNKNOWN)
+        {
+            return;
+        }
+
+        // TranslationService reads the prompt template off the agent it is handed, and only the
+        // AI Assistant defines it. Fall back to that agent when the executing one has no template,
+        // which is the normal case for the task agents reaching us through InstructDirect.
+        var host = agent;
+        if (host?.Templates?.Any(x => x.Name == TranslationPromptName) != true)
+        {
+            var agentService = _services.GetRequiredService<IAgentService>();
+            host = await agentService.LoadAgent(BuiltInAgentId.AIAssistant);
+        }
+
+        var translator = _services.GetRequiredService<ITranslationService>();
+        message.SecondaryContent = message.Content;
+        message.Content = await translator.Translate(host, message.MessageId, message.Content,
+            language: LanguageType.ENGLISH,
+            clone: false);
+    }
+}
diff --git a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.cs b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.cs
index 273f19913..73569f756 100644
--- a/src/Infrastructure/BotSharp.Core/Routing/RoutingService.cs
+++ b/src/Infrastructure/BotSharp.Core/Routing/RoutingService.cs
@@ -30,6 +30,11 @@ public async Task<RoleDialogModel> InstructDirect(Agent agent, RoleDialogModel m
     {
         var conv = _services.GetRequiredService<IConversationService>();
         var storage = _services.GetRequiredService<IConversationStorage>();
+
+        // Must run before the message is persisted so the stored record matches InstructLoop:
+        // Content in English, the user's original text in SecondaryContent.
+        await TranslateInboundMessage(agent, message);
+
         await storage.Append(conv.ConversationId, message);
 
         dialogs.Add(message);