diff --git a/bookstack_agent/ui/app/components/chat-page.tsx b/bookstack_agent/ui/app/components/chat-page.tsx
index f953d51..4c79a8b 100644
--- a/bookstack_agent/ui/app/components/chat-page.tsx
+++ b/bookstack_agent/ui/app/components/chat-page.tsx
@@ -220,8 +220,12 @@ export default function ChatPage({ user }: { user: User | null }) {
               setSessionId(event.session_id as string)
               break
 
+            case 'text_clear':
+              // Model emitted reasoning/thinking text before a tool call — discard it
+              patchLast((msg) => ({ ...msg, content: null }))
+              break
+
             case 'tool_use':
-              // Clear any in-progress streamed text (it was planning text, not the answer)
               patchLast((msg) => ({
                 ...msg,
                 content:   null,
diff --git a/src/aieng_bot/bookstack/agent.py b/src/aieng_bot/bookstack/agent.py
index 898b255..db83217 100644
--- a/src/aieng_bot/bookstack/agent.py
+++ b/src/aieng_bot/bookstack/agent.py
@@ -244,8 +244,12 @@ async def ask_stream(
             for _ in range(self.MAX_TURNS):
                 accumulated_text = ""
                 final_response: Any = None
+                # Set to True the moment a tool_use content block starts so we
+                # can immediately clear the UI and stop forwarding text chunks.
+                # On-prem models (e.g. Qwen) emit reasoning text before tool
+                # calls; we must not show that transient text to the user.
+                tool_use_started = False
 
-                # Use the streaming API so text tokens flow to the client immediately
                 async with self._async_client.messages.stream(
                     model=self.model,
                     max_tokens=8192,
@@ -254,9 +258,23 @@ async def ask_stream(
                     messages=cast(list[MessageParam], messages),
                 ) as stream:
                     async for event in stream:
-                        # Yield text tokens as they arrive (only TextDelta has .text)
-                        if (
-                            getattr(event, "type", None) == "content_block_delta"
+                        event_type = getattr(event, "type", None)
+
+                        if event_type == "content_block_start":
+                            block = getattr(event, "content_block", None)
+                            if (
+                                getattr(block, "type", None) == "tool_use"
+                                and not tool_use_started
+                            ):
+                                tool_use_started = True
+                                # Immediately tell the UI to discard any text
+                                # it has already rendered for this turn.
+                                if accumulated_text:
+                                    yield {"type": "text_clear"}
+
+                        elif (
+                            not tool_use_started
+                            and event_type == "content_block_delta"
                             and getattr(getattr(event, "delta", None), "type", None)
                             == "text_delta"
                         ):