Fix: edge connection logic (self-connect and duplicate connections)

app/w/[id]/components/workflow-block/components/sub-block/components/condition-input.tsx

@@ -440,6 +440,11 @@ export function ConditionInput({ blockId, subBlockId, isConnecting }: ConditionI
               }}
               isConnectableStart={true}
               isConnectableEnd={false}
+              isValidConnection={(connection) => {
+                const sourceNodeId = connection.source?.split('-')[0]
+                const targetNodeId = connection.target?.split('-')[0]
+                return sourceNodeId !== targetNodeId
+              }}
             />
             <div className="flex items-center gap-1">
               <Tooltip>

app/w/[id]/components/workflow-block/workflow-block.tsx

@@ -191,6 +191,7 @@ export function WorkflowBlock({ id, data, selected }: NodeProps<WorkflowBlockPro
         data-handleid="target"
         isConnectableStart={false}
         isConnectableEnd={true}
+        isValidConnection={(connection) => connection.source !== id}
       />
 
       {/* Block Header */}
@@ -284,6 +285,7 @@ export function WorkflowBlock({ id, data, selected }: NodeProps<WorkflowBlockPro
           data-handleid="source"
           isConnectableStart={true}
           isConnectableEnd={false}
+          isValidConnection={(connection) => connection.target !== id}
         />
       )}
     </Card>

stores/workflow/store.ts

@@ -186,6 +186,20 @@ export const useWorkflowStore = create<WorkflowStoreWithHistory>()(
       },
 
       addEdge: (edge: Edge) => {
+        // Check for duplicate connections
+        const isDuplicate = get().edges.some(
+          (existingEdge) =>
+            existingEdge.source === edge.source &&
+            existingEdge.target === edge.target &&
+            existingEdge.sourceHandle === edge.sourceHandle &&
+            existingEdge.targetHandle === edge.targetHandle
+        )
+
+        // If it's a duplicate connection, return early without adding the edge
+        if (isDuplicate) {
+          return
+        }
+
         const newEdge = {
           id: edge.id || crypto.randomUUID(),
           source: edge.source,