fix: always show chat tool icons (#4525)

* fix: always show chat tool icons, gray out when model doesn't support them

Tool icons (Think, Search, Code) were hidden unless a model was loaded
and supported those features. Now they're always visible so users can
see and pre-select them. If a loaded model doesn't support a feature,
the button gets grayed out and disabled instead of being removed.

* refactor: centralize Qwen thinking params in store

* fix: disable tool buttons when no model is loaded

Change disabled condition from `modelLoaded && !supportsX` to
`!modelLoaded || !supportsX` so buttons are grayed out both when
no model is loaded and when the loaded model lacks the capability.

* Fix Qwen3 param clobbering and restore SuggestionItem capability guards

- Revert setReasoningEnabled() in the store to a pure boolean setter.
  Moving the Qwen3 param logic into it caused reconnect/load/refresh
  paths (which also call setReasoningEnabled) to silently overwrite
  user-customized or server-provided temperature/topP/topK/minP.

- Restore applyQwenThinkingParams() as a standalone function called
  only from explicit user toggle click handlers in thread.tsx and
  shared-composer.tsx, matching the pre-PR behavior.

- Re-add supportsReasoning/supportsTools guards in the SuggestionItem
  click handler so that clicking a suggestion card only activates
  tool toggles the loaded model actually supports.

---------

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

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

@@ -132,13 +132,7 @@ const SuggestionItem: FC = () => {
   const prompt = useAuiState(({ suggestion }) => suggestion.prompt);
   const isDisabled = useAuiState(({ thread }) => thread.isDisabled);
   const isRunning = useAuiState(({ thread }) => thread.isRunning);
-  const supportsTools = useChatRuntimeStore((s) => s.supportsTools);
-  const supportsReasoning = useChatRuntimeStore((s) => s.supportsReasoning);
-  const allTools = SUGGESTION_TOOLS[prompt] ?? [];
-  const tools = allTools.filter((tool) => {
-    if (tool === "thinking") return supportsReasoning;
-    return supportsTools;
-  });
+  const tools = SUGGESTION_TOOLS[prompt] ?? [];
 
   return (
     <button
@@ -335,9 +329,6 @@ function applyQwenThinkingParams(thinkingOn: boolean): void {
   const store = useChatRuntimeStore.getState();
   const checkpoint = store.params.checkpoint?.toLowerCase() ?? "";
   if (!checkpoint.includes("qwen3")) return;
-  // Qwen3 & Qwen3.5 share the same recommended settings:
-  // Thinking ON (general): temp=1.0, top_p=0.95, top_k=20
-  // Thinking OFF (general): temp=0.7, top_p=0.8, top_k=20
   const params = thinkingOn
     ? { temperature: 0.6, topP: 0.95, topK: 20, minP: 0.0 }
     : { temperature: 0.7, topP: 0.8, topK: 20, minP: 0.0 };
@@ -345,15 +336,18 @@ function applyQwenThinkingParams(thinkingOn: boolean): void {
 }
 
 const ReasoningToggle: FC = () => {
+  const modelLoaded = useChatRuntimeStore(
+    (s) => !!s.params.checkpoint && !s.modelLoading,
+  );
   const supportsReasoning = useChatRuntimeStore((s) => s.supportsReasoning);
   const reasoningEnabled = useChatRuntimeStore((s) => s.reasoningEnabled);
   const setReasoningEnabled = useChatRuntimeStore((s) => s.setReasoningEnabled);
-
-  if (!supportsReasoning) return null;
+  const disabled = !modelLoaded || !supportsReasoning;
 
   return (
     <button
       type="button"
+      disabled={disabled}
       onClick={() => {
         const next = !reasoningEnabled;
         setReasoningEnabled(next);
@@ -361,13 +355,15 @@ const ReasoningToggle: FC = () => {
       }}
       className={cn(
         "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
-        reasoningEnabled
-          ? "bg-primary/10 text-primary hover:bg-primary/20"
-          : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
+        disabled
+          ? "cursor-not-allowed opacity-40"
+          : reasoningEnabled
+            ? "bg-primary/10 text-primary hover:bg-primary/20"
+            : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
       )}
       aria-label={reasoningEnabled ? "Disable thinking" : "Enable thinking"}
     >
-      {reasoningEnabled ? (
+      {reasoningEnabled && !disabled ? (
         <LightbulbIcon className="size-3.5" />
       ) : (
         <LightbulbOffIcon className="size-3.5" />
@@ -378,21 +374,26 @@ const ReasoningToggle: FC = () => {
 };
 
 const WebSearchToggle: FC = () => {
+  const modelLoaded = useChatRuntimeStore(
+    (s) => !!s.params.checkpoint && !s.modelLoading,
+  );
   const supportsTools = useChatRuntimeStore((s) => s.supportsTools);
   const toolsEnabled = useChatRuntimeStore((s) => s.toolsEnabled);
   const setToolsEnabled = useChatRuntimeStore((s) => s.setToolsEnabled);
-
-  if (!supportsTools) return null;
+  const disabled = !modelLoaded || !supportsTools;
 
   return (
     <button
       type="button"
+      disabled={disabled}
       onClick={() => setToolsEnabled(!toolsEnabled)}
       className={cn(
         "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
-        toolsEnabled
-          ? "bg-primary/10 text-primary hover:bg-primary/20"
-          : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
+        disabled
+          ? "cursor-not-allowed opacity-40"
+          : toolsEnabled
+            ? "bg-primary/10 text-primary hover:bg-primary/20"
+            : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
       )}
       aria-label={toolsEnabled ? "Disable web search" : "Enable web search"}
     >
@@ -403,23 +404,28 @@ const WebSearchToggle: FC = () => {
 };
 
 const CodeToolsToggle: FC = () => {
+  const modelLoaded = useChatRuntimeStore(
+    (s) => !!s.params.checkpoint && !s.modelLoading,
+  );
   const supportsTools = useChatRuntimeStore((s) => s.supportsTools);
   const codeToolsEnabled = useChatRuntimeStore((s) => s.codeToolsEnabled);
   const setCodeToolsEnabled = useChatRuntimeStore(
     (s) => s.setCodeToolsEnabled,
   );
-
-  if (!supportsTools) return null;
+  const disabled = !modelLoaded || !supportsTools;
 
   return (
     <button
       type="button"
+      disabled={disabled}
       onClick={() => setCodeToolsEnabled(!codeToolsEnabled)}
       className={cn(
         "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
-        codeToolsEnabled
-          ? "bg-primary/10 text-primary hover:bg-primary/20"
-          : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
+        disabled
+          ? "cursor-not-allowed opacity-40"
+          : codeToolsEnabled
+            ? "bg-primary/10 text-primary hover:bg-primary/20"
+            : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
       )}
       aria-label={codeToolsEnabled ? "Disable code execution" : "Enable code execution"}
     >

studio/frontend/src/features/chat/shared-composer.tsx

@@ -237,6 +237,9 @@ export function SharedComposer({
     const checkpoint = s.params.checkpoint;
     return s.models.find((m) => m.id === checkpoint);
   });
+  const modelLoaded = useChatRuntimeStore(
+    (s) => !!s.params.checkpoint && !s.modelLoading,
+  );
   const supportsReasoning = useChatRuntimeStore((s) => s.supportsReasoning);
   const reasoningEnabled = useChatRuntimeStore((s) => s.reasoningEnabled);
   const setReasoningEnabled = useChatRuntimeStore((s) => s.setReasoningEnabled);
@@ -245,6 +248,8 @@ export function SharedComposer({
   const setToolsEnabled = useChatRuntimeStore((s) => s.setToolsEnabled);
   const codeToolsEnabled = useChatRuntimeStore((s) => s.codeToolsEnabled);
   const setCodeToolsEnabled = useChatRuntimeStore((s) => s.setCodeToolsEnabled);
+  const reasoningDisabled = !modelLoaded || !supportsReasoning;
+  const toolsDisabled = !modelLoaded || !supportsTools;
   const setPendingAudioStore = useChatRuntimeStore((s) => s.setPendingAudio);
   const clearPendingAudioStore = useChatRuntimeStore((s) => s.clearPendingAudio);
 
@@ -519,70 +524,73 @@ export function SharedComposer({
               </TooltipIconButton>
             </>
           )}
-          {supportsReasoning && (
-            <button
-              type="button"
-              onClick={() => {
-                const next = !reasoningEnabled;
-                setReasoningEnabled(next);
-                // Qwen3/3.5: adjust params for thinking on/off
-                const store = useChatRuntimeStore.getState();
-                const cp = store.params.checkpoint?.toLowerCase() ?? "";
-                if (cp.includes("qwen3")) {
-                  const p = next
-                    ? { temperature: 0.6, topP: 0.95, topK: 20, minP: 0.0 }
-                    : { temperature: 0.7, topP: 0.8, topK: 20, minP: 0.0 };
-                  store.setParams({ ...store.params, ...p });
-                }
-              }}
-              className={cn(
-                "flex items-center gap-0.5 rounded-full px-2 py-0.5 text-xs font-medium transition-colors",
-                reasoningEnabled
+          <button
+            type="button"
+            disabled={reasoningDisabled}
+            onClick={() => {
+              const next = !reasoningEnabled;
+              setReasoningEnabled(next);
+              // Qwen3/3.5: adjust params for thinking on/off
+              const store = useChatRuntimeStore.getState();
+              const cp = store.params.checkpoint?.toLowerCase() ?? "";
+              if (cp.includes("qwen3")) {
+                const p = next
+                  ? { temperature: 0.6, topP: 0.95, topK: 20, minP: 0.0 }
+                  : { temperature: 0.7, topP: 0.8, topK: 20, minP: 0.0 };
+                store.setParams({ ...store.params, ...p });
+              }
+            }}
+            className={cn(
+              "flex items-center gap-0.5 rounded-full px-2 py-0.5 text-xs font-medium transition-colors",
+              reasoningDisabled
+                ? "cursor-not-allowed opacity-40"
+                : reasoningEnabled
                   ? "bg-primary/10 text-primary hover:bg-primary/20"
                   : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
-              )}
-              aria-label={reasoningEnabled ? "Disable thinking" : "Enable thinking"}
-            >
-              {reasoningEnabled ? (
-                <LightbulbIcon className="size-3" />
-              ) : (
-                <LightbulbOffIcon className="size-3" />
-              )}
-              <span>Think</span>
-            </button>
-          )}
-          {supportsTools && (
-            <button
-              type="button"
-              onClick={() => setToolsEnabled(!toolsEnabled)}
-              className={cn(
-                "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
-                toolsEnabled
+            )}
+            aria-label={reasoningEnabled ? "Disable thinking" : "Enable thinking"}
+          >
+            {reasoningEnabled && !reasoningDisabled ? (
+              <LightbulbIcon className="size-3" />
+            ) : (
+              <LightbulbOffIcon className="size-3" />
+            )}
+            <span>Think</span>
+          </button>
+          <button
+            type="button"
+            disabled={toolsDisabled}
+            onClick={() => setToolsEnabled(!toolsEnabled)}
+            className={cn(
+              "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
+              toolsDisabled
+                ? "cursor-not-allowed opacity-40"
+                : toolsEnabled
                   ? "bg-primary/10 text-primary hover:bg-primary/20"
                   : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
-              )}
-              aria-label={toolsEnabled ? "Disable web search" : "Enable web search"}
-            >
-              <GlobeIcon className="size-3.5" />
-              <span>Search</span>
-            </button>
-          )}
-          {supportsTools && (
-            <button
-              type="button"
-              onClick={() => setCodeToolsEnabled(!codeToolsEnabled)}
-              className={cn(
-                "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
-                codeToolsEnabled
+            )}
+            aria-label={toolsEnabled ? "Disable web search" : "Enable web search"}
+          >
+            <GlobeIcon className="size-3.5" />
+            <span>Search</span>
+          </button>
+          <button
+            type="button"
+            disabled={toolsDisabled}
+            onClick={() => setCodeToolsEnabled(!codeToolsEnabled)}
+            className={cn(
+              "flex items-center gap-1.5 rounded-full px-2.5 py-1 text-xs font-medium transition-colors",
+              toolsDisabled
+                ? "cursor-not-allowed opacity-40"
+                : codeToolsEnabled
                   ? "bg-primary/10 text-primary hover:bg-primary/20"
                   : "bg-muted text-muted-foreground hover:bg-muted-foreground/15",
-              )}
-              aria-label={codeToolsEnabled ? "Disable code execution" : "Enable code execution"}
-            >
-              <TerminalIcon className="size-3.5" />
-              <span>Code</span>
-            </button>
-          )}
+            )}
+            aria-label={codeToolsEnabled ? "Disable code execution" : "Enable code execution"}
+          >
+            <TerminalIcon className="size-3.5" />
+            <span>Code</span>
+          </button>
         </div>
         <div className="flex items-center gap-1">
           {dictationSupported && (