fix(agent): resolve permission schema and UI flash issues

Agent Bridge:
- Make sessionId optional in PermissionResponseSchema (fixes permission_response error)
- Add build:dev script for compiling sidecar binary
- Document agent-bridge rebuild workflow in CLAUDE.md

Chat UI:
- Add .no-transitions class to prevent tool widget flash during conversation switch
- Apply no-transitions during isTransitioning state
- Start BashToolWidget collapsed to avoid async Shiki flash
- Simplify send/stop button to single component with state-based styling

Sidebar:
- Skip creating new conversation if current one is empty (Untitled)
- Skip loading conversation if already viewing it

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: fazxes

CLAUDE.md

@@ -161,6 +161,30 @@ This command:
 | CSS/Tailwind                         | Instant HMR via Vite        |
 | Rust (`src-tauri/`)                  | Auto-rebuilds, restarts app |
 | Rust crates (`crates/`)              | Auto-rebuilds, restarts app |
+| agent-bridge (`agent-bridge/`)       | **Manual rebuild required** |
+
+### Agent Bridge Sidecar (IMPORTANT)
+
+The agent-bridge is a **compiled Bun binary** that Tauri spawns as a sidecar process. Unlike other code, **changes to agent-bridge require manual rebuilding**:
+
+```bash
+cd agent-bridge
+npm run build:dev    # Compiles to target/debug/agent-bridge
+```
+
+Then restart the Tauri app (`Cmd+C` → `pnpm tauri dev`).
+
+**Why manual rebuild?**
+
+- Tauri watches Rust code, not the agent-bridge TypeScript
+- The sidecar is a standalone binary (58MB) with embedded Bun runtime
+- Located at `target/debug/agent-bridge` in dev mode
+
+**Two build outputs:**
+| Script | Output | Purpose |
+|--------|--------|---------|
+| `npm run build` | `dist/index.js` | JS bundle (requires Bun to run) |
+| `npm run build:dev` | `target/debug/agent-bridge` | Standalone binary for Tauri |
 
 ### Production Build
 

agent-bridge/package.json

@@ -7,6 +7,7 @@
   "scripts": {
     "build": "bun build src/index.ts --outdir dist --target bun --sourcemap=external",
     "build:bundle": "bun build src/index.ts --outdir dist --target bun --minify",
+    "build:dev": "bun build --compile --target=bun-darwin-arm64 src/index.ts --outfile ../target/debug/agent-bridge",
     "dev": "bun --watch src/index.ts",
     "typecheck": "tsc --noEmit",
     "start": "bun src/index.ts"

agent-bridge/src/schemas.ts

@@ -125,7 +125,7 @@ export type SlashCommandDefinition = z.infer<typeof SlashCommandDefinitionSchema
 
 export const PermissionResponseSchema = z
   .object({
-    sessionId: z.string(),
+    sessionId: z.string().optional(), // Optional - permission lookup uses requestId only
     requestId: z.string(),
     decision: DecisionSchema,
     always: z.boolean(),

apps/agent/src/components/chat/chat-messages.tsx

@@ -149,7 +149,7 @@ export const ChatMessages: FC<ChatMessagesProps> = ({
   return (
     <div
       ref={containerRef}
-      className="flex-1 overflow-y-auto overflow-x-hidden p-4"
+      className={`flex-1 overflow-y-auto overflow-x-hidden p-4${isTransitioning ? ' no-transitions' : ''}`}
       style={{
         scrollbarGutter: 'stable both-edges',
         visibility: isTransitioning ? 'hidden' : 'visible',

apps/agent/src/components/chat/input/chat-input.tsx

@@ -760,47 +760,38 @@ export const ChatInput: FC<ChatInputProps> = ({
                 </ContextContentBody>
               </ContextContent>
             </Context>
-            {/* Send/Stop Button */}
-            {isAgentRunning && isInputEmpty ? (
-              <Tooltip>
-                <TooltipTrigger asChild>
-                  <button
-                    onClick={onStop}
-                    className={cn(
-                      'h-7 w-7 flex items-center justify-center rounded-full',
-                      'bg-destructive text-destructive-foreground',
-                      'transition-all duration-150',
-                      'hover:bg-destructive/90 hover:scale-105',
-                      'active:scale-95',
-                      'focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring/50'
-                    )}
-                  >
-                    <Square className="h-3 w-3 fill-current" />
-                  </button>
-                </TooltipTrigger>
-                <TooltipContent>Stop (Esc)</TooltipContent>
-              </Tooltip>
-            ) : (
-              <Tooltip>
-                <TooltipTrigger asChild>
-                  <button
-                    onClick={handleSend}
-                    disabled={isInputEmpty}
-                    className={cn(
-                      'h-7 w-7 flex items-center justify-center rounded-full',
-                      'transition-all duration-150',
-                      'focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring/50',
-                      isInputEmpty
+            {/* Send/Stop Button - Single button with state-based styling */}
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <button
+                  onClick={isAgentRunning && isInputEmpty ? onStop : handleSend}
+                  disabled={!isAgentRunning && isInputEmpty}
+                  className={cn(
+                    'h-7 w-7 flex items-center justify-center rounded-full',
+                    'transition-all duration-200 ease-out',
+                    'focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring/50',
+                    isAgentRunning && isInputEmpty
+                      ? 'bg-red-400/80 text-white dark:bg-red-400/70 hover:bg-red-400/90 dark:hover:bg-red-400/80'
+                      : isInputEmpty
                         ? 'bg-muted/50 text-muted-foreground/50 cursor-not-allowed'
                         : 'bg-primary text-primary-foreground hover:bg-primary/90 hover:scale-105 hover:shadow-[0_0_16px_-2px_var(--primary)] active:scale-95'
-                    )}
-                  >
+                  )}
+                >
+                  {isAgentRunning && isInputEmpty ? (
+                    <Square className="h-2.5 w-2.5 fill-current" strokeWidth={0} />
+                  ) : (
                     <ArrowUp className="h-4 w-4" />
-                  </button>
-                </TooltipTrigger>
-                <TooltipContent>{isAgentRunning ? 'Queue message' : 'Send message'}</TooltipContent>
-              </Tooltip>
-            )}
+                  )}
+                </button>
+              </TooltipTrigger>
+              <TooltipContent>
+                {isAgentRunning && isInputEmpty
+                  ? 'Stop (Esc)'
+                  : isAgentRunning
+                    ? 'Queue message'
+                    : 'Send message'}
+              </TooltipContent>
+            </Tooltip>
           </div>
         </div>
       </div>

apps/agent/src/components/chat/tools/bash-tool-widget.tsx

@@ -19,7 +19,8 @@ export const BashToolWidget: FC<BashToolWidgetProps> = ({
   output,
   isRunning = false,
 }) => {
-  const [isExpanded, setIsExpanded] = useState(true);
+  // Start collapsed to prevent layout flash from async Shiki highlighting
+  const [isExpanded, setIsExpanded] = useState(false);
   const [highlightedCommand, setHighlightedCommand] = useState<string>('');
 
   // Syntax highlight the command

apps/agent/src/components/layout/primary-sidebar.tsx

@@ -97,15 +97,24 @@ export const PrimarySidebar: FC<PrimarySidebarProps> = ({ width }) => {
   const [activeTab, setActiveTab] = useState<SidebarTab>('conversations');
 
   const handleStartConversation = useCallback((): void => {
+    // Skip if current conversation is empty (title still "Untitled" means no message sent)
+    const activeConv = conversations.find((c) => c.sessionId === activeConversationId);
+    if (activeConv?.title === 'Untitled') {
+      return;
+    }
     postMessage({
       type: 'conversation:create',
       uuid: crypto.randomUUID(),
       title: 'Untitled',
     });
-  }, [postMessage]);
+  }, [conversations, activeConversationId, postMessage]);
 
   const handleLoadConversation = useCallback(
     (sessionId: string): void => {
+      // Skip if already viewing this conversation
+      if (sessionId === activeConversationId) {
+        return;
+      }
       // Set loading and transitioning states SYNCHRONOUSLY before any async work
       // This ensures opacity-0 is applied before new content renders
       setLoadingConversation(true);
@@ -117,7 +126,7 @@ export const PrimarySidebar: FC<PrimarySidebarProps> = ({ width }) => {
         session_id: sessionId,
       });
     },
-    [setLoadingConversation, setConversationTransitioning, postMessage]
+    [activeConversationId, setLoadingConversation, setConversationTransitioning, postMessage]
   );
 
   const handleOpenQuickSearch = useCallback((): void => {

apps/agent/src/globals.css

@@ -664,6 +664,7 @@ html.dark [data-streamdown="code-block-container"] {
       opacity: 0.5;
     }
   }
+
 }
 
 /* Scrollbar styling for WKWebView */
@@ -735,6 +736,12 @@ html.dark ::-webkit-scrollbar-thumb:hover {
   contain: layout style paint;
 }
 
+/* Disable all transitions during conversation switching to prevent layout flash */
+.no-transitions,
+.no-transitions * {
+  transition: none !important;
+}
+
 /* For file tree items */
 .file-tree-item {
   content-visibility: auto;