fix: streaming 2

lib/core/services/api_service.dart

@@ -2649,7 +2649,9 @@ class ApiService {
 
     // Add only essential parameters
     if (conversationId != null) {
-      data['chat_id'] = conversationId;
+      if (conversationId != null) {
+        data['chat_id'] = conversationId;
+      }
     }
 
     // Add feature flags if enabled
@@ -2729,14 +2731,26 @@ class ApiService {
     debugPrint('DEBUG: session_id value: ${data['session_id']}');
     debugPrint('DEBUG: id value: ${data['id']}');
 
-    // If tools are requested, use background task flow to allow server-side execution.
+    // Decide whether to use background task flow.
-    // Open WebUI executes tools and continues the response outside of the
+    // Only enable background task mode when we actually need socket/dynamic-channel
-    // provider SSE. That path requires background task mode (session_id + id + chat_id).
+    // behavior (e.g., provider-native tools or explicit background tasks with a session).
-    if (conversationId != null) {
+    final bool useBackgroundTasks = (
+      // Use background flow only for provider-native tools or explicit tool servers.
+      // Pure text generation should prefer SSE even if a socket session exists,
+      // and background_tasks can still be honored at the end of SSE.
+      (toolIds != null && toolIds.isNotEmpty) ||
+      (toolServers != null && toolServers.isNotEmpty)
+    );
+
+    // Use background flow only when required; otherwise prefer SSE even with chat_id.
+    // SSE must not include session_id/id to avoid server falling back to task mode.
+    if (useBackgroundTasks) {
       // Attach identifiers to trigger background task processing on the server
       data['session_id'] = sessionId;
       data['id'] = messageId;
-      data['chat_id'] = conversationId;
+      if (conversationId != null) {
+        data['chat_id'] = conversationId;
+      }
 
       // Attach background_tasks if provided
       if (backgroundTasks != null && backgroundTasks.isNotEmpty) {
@@ -2773,7 +2787,10 @@ class ApiService {
         }
       }();
     } else {
-      // Use SSE streaming with proper parser
+      // Ensure we do not leak background-only identifiers into SSE path
+      data.remove('session_id');
+      data.remove('id');
+      // Use SSE streaming with proper parser (chat_id allowed)
       _streamSSE(data, streamController, messageId);
     }
 

lib/features/chat/providers/chat_providers.dart

@@ -1073,7 +1073,13 @@ Future<void> _sendMessageInternal(
     // In that case, do NOT suppress socket content.
     // Suppress socket TEXT content when we already have a stream (SSE or polling)
     // but DO allow tool_call status via socket to surface tiles immediately.
-    bool suppressSocketContent = (socketSessionId == null); // text-only suppression
+    // By default we already have an SSE/polling stream for content,
+    // so suppress socket TEXT chunks to avoid duplicates. We'll still
+    // surface tool_calls status via socket immediately. If the server
+    // switches us to a dynamic channel (request:chat:completion), we
+    // keep suppressing chat-events text but stream from that channel.
+    bool suppressSocketContent = true; // text-only suppression by default
+    bool usingDynamicChannel = false; // set true when server provides a channel
     if (socketService != null) {
       void chatHandler(Map<String, dynamic> ev) {
         try {
@@ -1281,6 +1287,7 @@ Future<void> _sendMessageInternal(
             if (channel is String && channel.isNotEmpty) {
               // Prefer dynamic channel for streaming content; suppress chat-events text to avoid duplicates
               suppressSocketContent = true;
+              usingDynamicChannel = true;
               if (kSocketVerboseLogging) {
                 DebugLogger.stream('Socket request:chat:completion channel=$channel');
               }
@@ -1720,7 +1727,8 @@ Future<void> _sendMessageInternal(
         suppressSocketContent = false;
         // If this path was SSE-driven (no background socket), finish now.
         // Otherwise keep streaming state until socket/dynamic channel signals done.
-        if (socketService == null) {
+        // We can safely finish on SSE completion when not using a dynamic channel.
+        if (!usingDynamicChannel) {
           ref.read(chatMessagesProvider.notifier).finishStreaming();
         }