fix(cli-viewer): resolve duplicate CLI output and sticky scroll button issues

- Create centralized useCliStreamWebSocket hook with module-level
  message tracking to ensure each WebSocket message is processed only once globally
- Replace position:absolute with position:sticky + flexbox wrapper
  for scroll-to-bottom buttons to fix viewport positioning
- Remove duplicate WebSocket handling from CliViewerPage, CliStreamMonitorLegacy,
  and CliStreamMonitorNew components

Fixes:
- CLI output no longer duplicated when multiple components subscribe
  to the same WebSocket feed
- Scroll-to-bottom button now stays fixed at bottom-right corner
  of viewport instead of scrolling with content

ccw/frontend/src/components/shared/CliStreamMonitor/CliStreamMonitorNew.tsx

@@ -3,15 +3,15 @@
 // ========================================
 // Redesigned CLI streaming monitor with smart parsing and message-based layout
 
-import { useEffect, useState, useCallback, useMemo, useRef } from 'react';
+import { useState, useCallback, useMemo } from 'react';
 import { useIntl } from 'react-intl';
 import {
   Terminal,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { useCliStreamStore, type CliOutputLine } from '@/stores/cliStreamStore';
-import { useNotificationStore, selectWsLastMessage } from '@/stores';
+import { useActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
-import { useActiveCliExecutions, useInvalidateActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
+import { useCliStreamWebSocket } from '@/hooks/useCliStreamWebSocket';
 
 // New layout components
 import { MonitorHeader } from './MonitorHeader';
@@ -24,37 +24,8 @@ import {
   ErrorMessage,
 } from './messages';
 
-// ========== Types for CLI WebSocket Messages ==========
+// ========== Types ==========
-
+// WebSocket message types are now handled centrally in useCliStreamWebSocket hook
-interface CliStreamStartedPayload {
-  executionId: string;
-  tool: string;
-  mode: string;
-  timestamp: string;
-}
-
-interface CliStreamOutputPayload {
-  executionId: string;
-  chunkType: string;
-  data: unknown;
-  unit?: {
-    content: unknown;
-    type?: string;
-  };
-}
-
-interface CliStreamCompletedPayload {
-  executionId: string;
-  success: boolean;
-  duration?: number;
-  timestamp: string;
-}
-
-interface CliStreamErrorPayload {
-  executionId: string;
-  error?: string;
-  timestamp: string;
-}
 
 // ========== Message Type Detection ==========
 
@@ -179,20 +150,6 @@ function parseOutputToMessages(
   return messages;
 }
 
-// ========== Helper Functions ==========
-
-function formatDuration(ms: number): string {
-  if (ms < 1000) return `${ms}ms`;
-  const seconds = Math.floor(ms / 1000);
-  if (seconds < 60) return `${seconds}s`;
-  const minutes = Math.floor(seconds / 60);
-  const remainingSeconds = seconds % 60;
-  if (minutes < 60) return `${minutes}m ${remainingSeconds}s`;
-  const hours = Math.floor(minutes / 60);
-  const remainingMinutes = minutes % 60;
-  return `${hours}h ${remainingMinutes}m`;
-}
-
 // ========== Component ==========
 
 export interface CliStreamMonitorNewProps {
@@ -215,104 +172,9 @@ export function CliStreamMonitorNew({ isOpen, onClose }: CliStreamMonitorNewProp
 
   // Active execution sync
   const { isLoading: isSyncing, refetch } = useActiveCliExecutions(isOpen);
-  const invalidateActive = useInvalidateActiveCliExecutions();
 
-  // WebSocket last message
+  // CENTRALIZED WebSocket handler - processes each message only once globally
-  const lastMessage = useNotificationStore(selectWsLastMessage);
+  useCliStreamWebSocket();
-
-  // Track last processed WebSocket message to prevent duplicate processing
-  const lastProcessedMsgRef = useRef<unknown>(null);
-
-  // Handle WebSocket messages (same as original)
-  useEffect(() => {
-    // Skip if no message or same message already processed (prevents React strict mode double-execution)
-    if (!lastMessage || lastMessage === lastProcessedMsgRef.current) return;
-    lastProcessedMsgRef.current = lastMessage;
-
-    const { type, payload } = lastMessage;
-
-    if (type === 'CLI_STARTED') {
-      const p = payload as CliStreamStartedPayload;
-      const startTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        tool: p.tool || 'cli',
-        mode: p.mode || 'analysis',
-        status: 'running',
-        startTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(startTime).toLocaleTimeString()}] CLI execution started: ${p.tool} (${p.mode} mode)`,
-            timestamp: startTime
-          }
-        ]
-      });
-      invalidateActive();
-    } else if (type === 'CLI_OUTPUT') {
-      const p = payload as CliStreamOutputPayload;
-      const unitContent = p.unit?.content ?? p.data;
-      const unitType = p.unit?.type || p.chunkType;
-
-      let content: string;
-      if (unitType === 'tool_call' && typeof unitContent === 'object' && unitContent !== null) {
-        const toolCall = unitContent as { action?: string; toolName?: string; parameters?: unknown; status?: string; output?: string };
-        if (toolCall.action === 'invoke') {
-          const params = toolCall.parameters ? JSON.stringify(toolCall.parameters) : '';
-          content = `[Tool] ${toolCall.toolName}(${params})`;
-        } else if (toolCall.action === 'result') {
-          const status = toolCall.status || 'unknown';
-          const output = toolCall.output ? `: ${toolCall.output.substring(0, 200)}${toolCall.output.length > 200 ? '...' : ''}` : '';
-          content = `[Tool Result] ${status}${output}`;
-        } else {
-          content = JSON.stringify(unitContent);
-        }
-      } else {
-        content = typeof unitContent === 'string' ? unitContent : JSON.stringify(unitContent);
-      }
-
-      const lines = content.split('\n');
-      const addOutput = useCliStreamStore.getState().addOutput;
-      lines.forEach(line => {
-        if (line.trim() || lines.length === 1) {
-          addOutput(p.executionId, {
-            type: (unitType as CliOutputLine['type']) || 'stdout',
-            content: line,
-            timestamp: Date.now()
-          });
-        }
-      });
-    } else if (type === 'CLI_COMPLETED') {
-      const p = payload as CliStreamCompletedPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: p.success ? 'completed' : 'error',
-        endTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(endTime).toLocaleTimeString()}] CLI execution ${p.success ? 'completed successfully' : 'failed'}${p.duration ? ` (${formatDuration(p.duration)})` : ''}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    } else if (type === 'CLI_ERROR') {
-      const p = payload as CliStreamErrorPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: 'error',
-        endTime,
-        output: [
-          {
-            type: 'stderr',
-            content: `[ERROR] ${p.error || 'Unknown error occurred'}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    }
-  }, [lastMessage, invalidateActive]);
 
   // Get execution stats
   const executionStats = useMemo(() => {

ccw/frontend/src/components/shared/CliStreamMonitor/MonitorBody/index.tsx

@@ -33,16 +33,18 @@ interface ScrollToBottomButtonProps {
 
 function ScrollToBottomButton({ onClick, className }: ScrollToBottomButtonProps) {
   return (
+    <div className="sticky bottom-4 flex justify-end">
       <Button
         size="sm"
         variant="secondary"
-      className={cn('absolute bottom-4 right-4 shadow-lg', className)}
+        className={cn('shadow-lg', className)}
         onClick={onClick}
         title="Scroll to bottom"
       >
         <ArrowDownToLine className="h-4 w-4 mr-1" />
         Scroll to bottom
       </Button>
+    </div>
   );
 }
 

ccw/frontend/src/components/shared/CliStreamMonitorLegacy.tsx

@@ -24,45 +24,16 @@ import { Tabs, TabsList, TabsTrigger } from '@/components/ui/Tabs';
 import { Badge } from '@/components/ui/Badge';
 import { LogBlockList } from '@/components/shared/LogBlock';
 import { useCliStreamStore, type CliOutputLine } from '@/stores/cliStreamStore';
-import { useNotificationStore, selectWsLastMessage } from '@/stores';
+import { useActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
-import { useActiveCliExecutions, useInvalidateActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
+import { useCliStreamWebSocket } from '@/hooks/useCliStreamWebSocket';
 
 // New components for Tab + JSON Cards
 import { ExecutionTab } from './CliStreamMonitor/components/ExecutionTab';
 import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
 
-// ========== Types for CLI WebSocket Messages ==========
+// ========== Types ==========
-
+// WebSocket message types are now handled centrally in useCliStreamWebSocket hook
-interface CliStreamStartedPayload {
-  executionId: string;
-  tool: string;
-  mode: string;
-  timestamp: string;
-}
-
-interface CliStreamOutputPayload {
-  executionId: string;
-  chunkType: string;
-  data: unknown;
-  unit?: {
-    content: unknown;
-    type?: string;
-  };
-}
-
-interface CliStreamCompletedPayload {
-  executionId: string;
-  success: boolean;
-  duration?: number;
-  timestamp: string;
-}
-
-interface CliStreamErrorPayload {
-  executionId: string;
-  error?: string;
-  timestamp: string;
-}
 
 // ========== Helper Functions ==========
 
@@ -209,9 +180,6 @@ export function CliStreamMonitor({ isOpen, onClose }: CliStreamMonitorProps) {
   // Track last output length to detect new output
   const lastOutputLengthRef = useRef<Record<string, number>>({});
 
-  // Track last processed WebSocket message to prevent duplicate processing
-  const lastProcessedMsgRef = useRef<unknown>(null);
-
   // Store state
   const executions = useCliStreamStore((state) => state.executions);
   const currentExecutionId = useCliStreamStore((state) => state.currentExecutionId);
@@ -221,105 +189,9 @@ export function CliStreamMonitor({ isOpen, onClose }: CliStreamMonitorProps) {
 
   // Active execution sync
   const { isLoading: isSyncing, refetch } = useActiveCliExecutions(isOpen);
-  const invalidateActive = useInvalidateActiveCliExecutions();
 
-  // WebSocket last message from notification store
+  // CENTRALIZED WebSocket handler - processes each message only once globally
-  const lastMessage = useNotificationStore(selectWsLastMessage);
+  useCliStreamWebSocket();
-
-  // Handle WebSocket messages for CLI stream
-  useEffect(() => {
-    // Skip if no message or same message already processed (prevents React strict mode double-execution)
-    if (!lastMessage || lastMessage === lastProcessedMsgRef.current) return;
-    lastProcessedMsgRef.current = lastMessage;
-
-    const { type, payload } = lastMessage;
-
-    if (type === 'CLI_STARTED') {
-      const p = payload as CliStreamStartedPayload;
-      const startTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        tool: p.tool || 'cli',
-        mode: p.mode || 'analysis',
-        status: 'running',
-        startTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(startTime).toLocaleTimeString()}] CLI execution started: ${p.tool} (${p.mode} mode)`,
-            timestamp: startTime
-          }
-        ]
-      });
-      // Set as current if none selected
-      if (!currentExecutionId) {
-        setCurrentExecution(p.executionId);
-      }
-      invalidateActive();
-    } else if (type === 'CLI_OUTPUT') {
-      const p = payload as CliStreamOutputPayload;
-      const unitContent = p.unit?.content ?? p.data;
-      const unitType = p.unit?.type || p.chunkType;
-
-      let content: string;
-      if (unitType === 'tool_call' && typeof unitContent === 'object' && unitContent !== null) {
-        const toolCall = unitContent as { action?: string; toolName?: string; parameters?: unknown; status?: string; output?: string };
-        if (toolCall.action === 'invoke') {
-          const params = toolCall.parameters ? JSON.stringify(toolCall.parameters) : '';
-          content = `[Tool] ${toolCall.toolName}(${params})`;
-        } else if (toolCall.action === 'result') {
-          const status = toolCall.status || 'unknown';
-          const output = toolCall.output ? `: ${toolCall.output.substring(0, 200)}${toolCall.output.length > 200 ? '...' : ''}` : '';
-          content = `[Tool Result] ${status}${output}`;
-        } else {
-          content = JSON.stringify(unitContent);
-        }
-      } else {
-        content = typeof unitContent === 'string' ? unitContent : JSON.stringify(unitContent);
-      }
-
-      const lines = content.split('\n');
-      const addOutput = useCliStreamStore.getState().addOutput;
-      lines.forEach(line => {
-        if (line.trim() || lines.length === 1) {
-          addOutput(p.executionId, {
-            type: (unitType as CliOutputLine['type']) || 'stdout',
-            content: line,
-            timestamp: Date.now()
-          });
-        }
-      });
-    } else if (type === 'CLI_COMPLETED') {
-      const p = payload as CliStreamCompletedPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: p.success ? 'completed' : 'error',
-        endTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(endTime).toLocaleTimeString()}] CLI execution ${p.success ? 'completed successfully' : 'failed'}${p.duration ? ` (${formatDuration(p.duration)})` : ''}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    } else if (type === 'CLI_ERROR') {
-      const p = payload as CliStreamErrorPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: 'error',
-        endTime,
-        output: [
-          {
-            type: 'stderr',
-            content: `[ERROR] ${p.error || 'Unknown error occurred'}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    }
-  }, [lastMessage, invalidateActive]);
 
   // Auto-scroll to bottom when new output arrives (optimized - only scroll when output length changes)
   useEffect(() => {

ccw/frontend/src/components/shared/StreamingOutput.tsx

@@ -125,15 +125,17 @@ export function StreamingOutput({
 
       {/* Scroll to bottom button */}
       {isUserScrolling && outputs.length > 0 && (
+        <div className="sticky bottom-3 flex justify-end">
           <Button
             size="sm"
             variant="secondary"
-          className="absolute bottom-3 right-3"
+            className="shadow-lg"
             onClick={scrollToBottom}
           >
             <ArrowDownToLine className="h-4 w-4 mr-1" />
             Scroll to bottom
           </Button>
+        </div>
       )}
     </div>
   );

ccw/frontend/src/hooks/useCliStreamWebSocket.ts

@@ -0,0 +1,202 @@
+// ========================================
+// useCliStreamWebSocket Hook
+// ========================================
+// Centralized WebSocket message handler for CLI stream
+// Ensures each message is processed ONLY ONCE across all components
+
+import { useEffect, useRef } from 'react';
+import { useNotificationStore, selectWsLastMessage } from '@/stores';
+import { useCliStreamStore, type CliOutputLine } from '@/stores/cliStreamStore';
+import { useInvalidateActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
+
+// ========== Module-level Message Tracking ==========
+// CRITICAL: This MUST be at module level to ensure single instance across all component mounts
+// Prevents duplicate message processing when multiple components subscribe to WebSocket
+let globalLastProcessedMsg: unknown = null;
+
+// ========== Types for CLI WebSocket Messages ==========
+
+interface CliStreamStartedPayload {
+  executionId: string;
+  tool: string;
+  mode: string;
+  timestamp: string;
+}
+
+interface CliStreamOutputPayload {
+  executionId: string;
+  chunkType: string;
+  data: unknown;
+  unit?: {
+    content: unknown;
+    type?: string;
+  };
+}
+
+interface CliStreamCompletedPayload {
+  executionId: string;
+  success: boolean;
+  duration?: number;
+  timestamp: string;
+}
+
+interface CliStreamErrorPayload {
+  executionId: string;
+  error?: string;
+  timestamp: string;
+}
+
+// ========== Helper Functions ==========
+
+function formatDuration(ms: number): string {
+  if (ms < 1000) return `${ms}ms`;
+  const seconds = Math.floor(ms / 1000);
+  if (seconds < 60) return `${seconds}s`;
+  const minutes = Math.floor(seconds / 60);
+  const remainingSeconds = seconds % 60;
+  if (minutes < 60) return `${minutes}m ${remainingSeconds}s`;
+  const hours = Math.floor(minutes / 60);
+  const remainingMinutes = minutes % 60;
+  return `${hours}h ${remainingMinutes}m`;
+}
+
+// ========== Hook ==========
+
+/**
+ * Centralized WebSocket handler for CLI stream messages
+ *
+ * IMPORTANT: This hook uses module-level state to ensure each WebSocket message
+ * is processed exactly ONCE, even when multiple components are mounted.
+ *
+ * Components should simply consume data from useCliStreamStore - no need to
+ * handle WebSocket messages individually.
+ *
+ * @example
+ * ```tsx
+ * // In your app root or layout component
+ * useCliStreamWebSocket();
+ *
+ * // In any component that needs CLI output
+ * const executions = useCliStreamStore(state => state.executions);
+ * ```
+ */
+export function useCliStreamWebSocket(): void {
+  const lastMessage = useNotificationStore(selectWsLastMessage);
+  const invalidateActive = useInvalidateActiveCliExecutions();
+
+  // Ref to track if this hook instance is active (for cleanup)
+  const isActiveRef = useRef(true);
+
+  useEffect(() => {
+    isActiveRef.current = true;
+
+    return () => {
+      isActiveRef.current = false;
+    };
+  }, []);
+
+  useEffect(() => {
+    // Skip if no message or already processed GLOBALLY
+    if (!lastMessage || lastMessage === globalLastProcessedMsg) return;
+
+    // Mark as processed immediately at module level
+    globalLastProcessedMsg = lastMessage;
+
+    // Check if hook is still active (component not unmounted)
+    if (!isActiveRef.current) return;
+
+    const { type, payload } = lastMessage;
+
+    if (type === 'CLI_STARTED') {
+      const p = payload as CliStreamStartedPayload;
+      const startTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
+      useCliStreamStore.getState().upsertExecution(p.executionId, {
+        tool: p.tool || 'cli',
+        mode: p.mode || 'analysis',
+        status: 'running',
+        startTime,
+        output: [
+          {
+            type: 'system',
+            content: `[${new Date(startTime).toLocaleTimeString()}] CLI execution started: ${p.tool} (${p.mode} mode)`,
+            timestamp: startTime
+          }
+        ]
+      });
+      invalidateActive();
+    } else if (type === 'CLI_OUTPUT') {
+      const p = payload as CliStreamOutputPayload;
+      const unitContent = p.unit?.content ?? p.data;
+      const unitType = p.unit?.type || p.chunkType;
+
+      let content: string;
+      if (unitType === 'tool_call' && typeof unitContent === 'object' && unitContent !== null) {
+        const toolCall = unitContent as { action?: string; toolName?: string; parameters?: unknown; status?: string; output?: string };
+        if (toolCall.action === 'invoke') {
+          const params = toolCall.parameters ? JSON.stringify(toolCall.parameters) : '';
+          content = `[Tool] ${toolCall.toolName}(${params})`;
+        } else if (toolCall.action === 'result') {
+          const status = toolCall.status || 'unknown';
+          const output = toolCall.output ? `: ${toolCall.output.substring(0, 200)}${toolCall.output.length > 200 ? '...' : ''}` : '';
+          content = `[Tool Result] ${status}${output}`;
+        } else {
+          content = JSON.stringify(unitContent);
+        }
+      } else {
+        content = typeof unitContent === 'string' ? unitContent : JSON.stringify(unitContent);
+      }
+
+      const lines = content.split('\n');
+      const addOutput = useCliStreamStore.getState().addOutput;
+      lines.forEach(line => {
+        if (line.trim() || lines.length === 1) {
+          addOutput(p.executionId, {
+            type: (unitType as CliOutputLine['type']) || 'stdout',
+            content: line,
+            timestamp: Date.now()
+          });
+        }
+      });
+    } else if (type === 'CLI_COMPLETED') {
+      const p = payload as CliStreamCompletedPayload;
+      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
+      useCliStreamStore.getState().upsertExecution(p.executionId, {
+        status: p.success ? 'completed' : 'error',
+        endTime,
+        output: [
+          {
+            type: 'system',
+            content: `[${new Date(endTime).toLocaleTimeString()}] CLI execution ${p.success ? 'completed successfully' : 'failed'}${p.duration ? ` (${formatDuration(p.duration)})` : ''}`,
+            timestamp: endTime
+          }
+        ]
+      });
+      invalidateActive();
+    } else if (type === 'CLI_ERROR') {
+      const p = payload as CliStreamErrorPayload;
+      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
+      useCliStreamStore.getState().upsertExecution(p.executionId, {
+        status: 'error',
+        endTime,
+        output: [
+          {
+            type: 'stderr',
+            content: `[ERROR] ${p.error || 'Unknown error occurred'}`,
+            timestamp: endTime
+          }
+        ]
+      });
+      invalidateActive();
+    }
+  }, [lastMessage, invalidateActive]);
+}
+
+/**
+ * Reset the global message tracker
+ * Useful for testing or when explicitly re-processing messages is needed
+ */
+export function resetCliStreamWebSocketTracker(): void {
+  globalLastProcessedMsg = null;
+}
+
+export default useCliStreamWebSocket;

ccw/frontend/src/pages/CliViewerPage.tsx

@@ -15,44 +15,9 @@ import {
   useFocusedPaneId,
   type AllotmentLayout,
 } from '@/stores/viewerStore';
-import { useCliStreamStore, type CliOutputLine } from '@/stores/cliStreamStore';
+import { useCliStreamStore } from '@/stores/cliStreamStore';
-import { useNotificationStore, selectWsLastMessage } from '@/stores';
+import { useActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
-import { useActiveCliExecutions, useInvalidateActiveCliExecutions } from '@/hooks/useActiveCliExecutions';
+import { useCliStreamWebSocket } from '@/hooks/useCliStreamWebSocket';
-
-// ========================================
-// Types
-// ========================================
-
-// CLI WebSocket message types (matching CliStreamMonitorLegacy)
-interface CliStreamStartedPayload {
-  executionId: string;
-  tool: string;
-  mode: string;
-  timestamp: string;
-}
-
-interface CliStreamOutputPayload {
-  executionId: string;
-  chunkType: string;
-  data: unknown;
-  unit?: {
-    content: unknown;
-    type?: string;
-  };
-}
-
-interface CliStreamCompletedPayload {
-  executionId: string;
-  success: boolean;
-  duration?: number;
-  timestamp: string;
-}
-
-interface CliStreamErrorPayload {
-  executionId: string;
-  error?: string;
-  timestamp: string;
-}
 
 // ========================================
 // Constants
@@ -64,18 +29,6 @@ const DEFAULT_LAYOUT = 'split-h' as const;
 // Helper Functions
 // ========================================
 
-function formatDuration(ms: number): string {
-  if (ms < 1000) return `${ms}ms`;
-  const seconds = Math.floor(ms / 1000);
-  if (seconds < 60) return `${seconds}s`;
-  const minutes = Math.floor(seconds / 60);
-  const remainingSeconds = seconds % 60;
-  if (minutes < 60) return `${minutes}m ${remainingSeconds}s`;
-  const hours = Math.floor(minutes / 60);
-  const remainingMinutes = minutes % 60;
-  return `${hours}h ${remainingMinutes}m`;
-}
-
 /**
  * Count total panes in layout
  */
@@ -113,105 +66,11 @@ export function CliViewerPage() {
   // CLI Stream Store hooks
   const executions = useCliStreamStore((state) => state.executions);
 
-  // Track last processed WebSocket message to prevent duplicate processing
-  const lastProcessedMsgRef = useRef<unknown>(null);
-
-  // WebSocket last message from notification store
-  const lastMessage = useNotificationStore(selectWsLastMessage);
-
   // Active execution sync from server
   useActiveCliExecutions(true);
-  const invalidateActive = useInvalidateActiveCliExecutions();
 
-  // Handle WebSocket messages for CLI stream (same logic as CliStreamMonitorLegacy)
+  // CENTRALIZED WebSocket handler - processes each message only ONCE globally
-  useEffect(() => {
+  useCliStreamWebSocket();
-    if (!lastMessage || lastMessage === lastProcessedMsgRef.current) return;
-    lastProcessedMsgRef.current = lastMessage;
-
-    const { type, payload } = lastMessage;
-
-    if (type === 'CLI_STARTED') {
-      const p = payload as CliStreamStartedPayload;
-      const startTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        tool: p.tool || 'cli',
-        mode: p.mode || 'analysis',
-        status: 'running',
-        startTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(startTime).toLocaleTimeString()}] CLI execution started: ${p.tool} (${p.mode} mode)`,
-            timestamp: startTime
-          }
-        ]
-      });
-      invalidateActive();
-    } else if (type === 'CLI_OUTPUT') {
-      const p = payload as CliStreamOutputPayload;
-      const unitContent = p.unit?.content ?? p.data;
-      const unitType = p.unit?.type || p.chunkType;
-
-      let content: string;
-      if (unitType === 'tool_call' && typeof unitContent === 'object' && unitContent !== null) {
-        const toolCall = unitContent as { action?: string; toolName?: string; parameters?: unknown; status?: string; output?: string };
-        if (toolCall.action === 'invoke') {
-          const params = toolCall.parameters ? JSON.stringify(toolCall.parameters) : '';
-          content = `[Tool] ${toolCall.toolName}(${params})`;
-        } else if (toolCall.action === 'result') {
-          const status = toolCall.status || 'unknown';
-          const output = toolCall.output ? `: ${toolCall.output.substring(0, 200)}${toolCall.output.length > 200 ? '...' : ''}` : '';
-          content = `[Tool Result] ${status}${output}`;
-        } else {
-          content = JSON.stringify(unitContent);
-        }
-      } else {
-        content = typeof unitContent === 'string' ? unitContent : JSON.stringify(unitContent);
-      }
-
-      const lines = content.split('\n');
-      const addOutput = useCliStreamStore.getState().addOutput;
-      lines.forEach(line => {
-        if (line.trim() || lines.length === 1) {
-          addOutput(p.executionId, {
-            type: (unitType as CliOutputLine['type']) || 'stdout',
-            content: line,
-            timestamp: Date.now()
-          });
-        }
-      });
-    } else if (type === 'CLI_COMPLETED') {
-      const p = payload as CliStreamCompletedPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: p.success ? 'completed' : 'error',
-        endTime,
-        output: [
-          {
-            type: 'system',
-            content: `[${new Date(endTime).toLocaleTimeString()}] CLI execution ${p.success ? 'completed successfully' : 'failed'}${p.duration ? ` (${formatDuration(p.duration)})` : ''}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    } else if (type === 'CLI_ERROR') {
-      const p = payload as CliStreamErrorPayload;
-      const endTime = p.timestamp ? new Date(p.timestamp).getTime() : Date.now();
-      useCliStreamStore.getState().upsertExecution(p.executionId, {
-        status: 'error',
-        endTime,
-        output: [
-          {
-            type: 'stderr',
-            content: `[ERROR] ${p.error || 'Unknown error occurred'}`,
-            timestamp: endTime
-          }
-        ]
-      });
-      invalidateActive();
-    }
-  }, [lastMessage, invalidateActive]);
 
   // Auto-add new executions as tabs, distributing across available panes
   const addedExecutionsRef = useRef<Set<string>>(new Set());