fix: clear tool status badge immediately after tool execution (#4733)

* fix: clear tool status badge immediately after tool execution

The tool status timer badge (Searching 1s, 2s...) persisted after
tool calls finished because the status clear event was only sent
at the start of the next generation iteration, not after tool
execution completed.

Backend: yield status clear after all tools finish in the agentic
loop iteration, before continue starts the next generation pass.

Frontend: debounce badge visibility by 300ms so sub-second tool
calls dont flash the badge.

* Fix debounce regression for consecutive tool calls

Only apply the 300ms show-delay when transitioning from idle to
tool-active. When switching between consecutive tools in the same
turn (e.g. web_search -> python), keep the badge visible immediately
so it does not flicker or disappear during multi-tool runs.

* Delay wasActiveRef reset to bridge inter-iteration tool gaps

The backend emits a status-clear event between tool iterations,
which was resetting wasActiveRef immediately and causing the next
tool to be re-debounced (300ms hidden gap between consecutive tools
in the same turn). Now the ref reset is delayed by 500ms so a
follow-up tool within the same agentic turn shows the badge
immediately, while a genuinely new turn still gets the debounce.

* Use thread lifecycle to track tool-run boundaries

Replace the 500ms wall-clock timeout with the actual thread.isRunning
state to determine when wasActiveRef should reset. This properly
handles all cases:
- Consecutive tools within the same run stay visible without flicker
- The badge hides only when the thread run actually ends
- New turns always get a fresh 300ms debounce on the first tool
- No heuristic timeout that can misfire on slow or fast inference

* Consolidate wasActiveRef reset into single effect

Removes the separate isThreadRunning effect to avoid a race where
the ref resets before the tool-status effect reads it (when
isThreadRunning flips to false before setToolStatus(null) from
the adapter's finally block). Now wasActiveRef resets only when
both toolStatus is null AND the thread run has ended, eliminating
any flicker on the last tool of a run.

* Simplify debounce: use visible state instead of ref tracking

Drop wasActiveRef entirely and use the visible state as the
debounce gate. When the badge is not yet on screen, debounce
for 300ms before showing. When already visible from a prior tool,
keep showing immediately. This correctly handles all cases:
- All fast tools (<300ms) are suppressed, not just the first
- Consecutive tools after the badge is shown stay visible
- Badge persists across inter-iteration clears while thread runs
- New turns get a fresh debounce after visible resets

---------

Co-authored-by: Daniel Han <danielhanchen@gmail.com>

studio/backend/core/inference/llama_cpp.py

@@ -2740,6 +2740,8 @@ class LlamaCppBackend:
                         tool_msg["tool_call_id"] = tool_call_id
                     conversation.append(tool_msg)
 
+                # Clear tool status badge before next generation iteration
+                yield {"type": "status", "text": ""}
                 # Continue the loop to let model respond with context
                 continue
 

studio/frontend/src/components/assistant-ui/thread.tsx

@@ -437,21 +437,40 @@ const CodeToolsToggle: FC = () => {
 
 const ToolStatusDisplay: FC = () => {
   const toolStatus = useChatRuntimeStore((s) => s.toolStatus);
+  const isThreadRunning = useAuiState(({ thread }) => thread.isRunning);
   const [elapsed, setElapsed] = useState(0);
+  const [visible, setVisible] = useState(false);
 
   useEffect(() => {
     if (!toolStatus) {
       setElapsed(0);
+      if (!isThreadRunning) {
+        setVisible(false);
+      }
       return;
     }
+
     setElapsed(0);
+
+    // Debounce badge visibility by 300ms when the badge is not
+    // already on screen. Once visible from a prior tool, consecutive
+    // tools show immediately so the badge does not flicker. Fast
+    // tool calls that all complete under 300ms never show the badge.
+    let showTimer: ReturnType<typeof setTimeout> | undefined;
+    if (!visible) {
+      showTimer = setTimeout(() => setVisible(true), 300);
+    }
+
     const interval = setInterval(() => {
       setElapsed((prev) => prev + 1);
     }, 1000);
-    return () => clearInterval(interval);
-  }, [toolStatus]);
+    return () => {
+      clearInterval(interval);
+      if (showTimer) clearTimeout(showTimer);
+    };
+  }, [toolStatus, isThreadRunning]);
 
-  if (!toolStatus) return null;
+  if (!toolStatus || !visible) return null;
   const isRunning = toolStatus.startsWith("Running");
   const StatusIcon = isRunning ? TerminalIcon : GlobeIcon;
   return (