diff --git a/src/web/src/features/rubros/components/CategoryTreeNode.tsx b/src/web/src/features/rubros/components/CategoryTreeNode.tsx
index 5cc95e1..058a809 100644
--- a/src/web/src/features/rubros/components/CategoryTreeNode.tsx
+++ b/src/web/src/features/rubros/components/CategoryTreeNode.tsx
@@ -101,11 +101,14 @@ export function CategoryTreeNode({
       {/* Action buttons — only if canEdit */}
       {canEdit && (
         <div className="flex items-center gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
+          {/* CAT-002: disabled when leaf-with-avisos; PRD-002 activates the real data path */}
           <Button
             variant="ghost"
             size="sm"
             className="h-6 w-6 p-0"
             aria-label={`Agregar subrubro en ${node.nombre}`}
+            disabled={node.tieneAvisos === true}
+            title={node.tieneAvisos === true ? 'El rubro contiene avisos asignados. Muévalos antes de agregar sub-rubros.' : undefined}
             onClick={() => onAddChild(node.id)}
           >
             <Plus className="h-3.5 w-3.5" />
diff --git a/src/web/src/features/rubros/types.ts b/src/web/src/features/rubros/types.ts
index d726135..c0da063 100644
--- a/src/web/src/features/rubros/types.ts
+++ b/src/web/src/features/rubros/types.ts
@@ -7,6 +7,8 @@ export interface RubroTreeNode {
   activo: boolean
   parentId: number | null
   tarifarioBaseId: number | null
+  // CAT-002: additive field — optional for backward-compat (PRD-002 always sends it)
+  tieneAvisos?: boolean
   hijos: RubroTreeNode[]
 }
 
diff --git a/src/web/src/tests/features/rubros/CategoryTree.test.tsx b/src/web/src/tests/features/rubros/CategoryTree.test.tsx
index 05aadae..99b9d22 100644
--- a/src/web/src/tests/features/rubros/CategoryTree.test.tsx
+++ b/src/web/src/tests/features/rubros/CategoryTree.test.tsx
@@ -110,6 +110,62 @@ describe('CategoryTree', () => {
   })
 })
 
+// ── CAT-002: tieneAvisos disables "Agregar subrubro" button ──────────────────
+
+describe('CategoryTreeNode tieneAvisos (CAT-002)', () => {
+  it('BotonAgregarSubrubro_Disabled_CuandoTieneAvisosTrue', () => {
+    const nodeConAvisos: RubroTreeNode = {
+      id: 10,
+      nombre: 'ConAvisos',
+      orden: 1,
+      activo: true,
+      parentId: null,
+      tarifarioBaseId: null,
+      tieneAvisos: true,
+      hijos: [],
+    }
+    render(
+      <CategoryTree
+        nodes={[nodeConAvisos]}
+        onEdit={noop}
+        onDelete={noop}
+        onAddChild={noop}
+        onMove={noop}
+        canEdit={true}
+      />,
+    )
+    const addBtn = screen.getByRole('button', { name: /agregar subrubro en conavisos/i })
+    expect(addBtn).toBeDisabled()
+    expect(addBtn).toHaveAttribute('title')
+    expect(addBtn.getAttribute('title')).toMatch(/El rubro contiene avisos/i)
+  })
+
+  it('BotonAgregarSubrubro_Enabled_CuandoTieneAvisosFalse', () => {
+    const nodeSinAvisos: RubroTreeNode = {
+      id: 11,
+      nombre: 'SinAvisos',
+      orden: 1,
+      activo: true,
+      parentId: null,
+      tarifarioBaseId: null,
+      tieneAvisos: false,
+      hijos: [],
+    }
+    render(
+      <CategoryTree
+        nodes={[nodeSinAvisos]}
+        onEdit={noop}
+        onDelete={noop}
+        onAddChild={noop}
+        onMove={noop}
+        canEdit={true}
+      />,
+    )
+    const addBtn = screen.getByRole('button', { name: /agregar subrubro en sinavisos/i })
+    expect(addBtn).not.toBeDisabled()
+  })
+})
+
 describe('CategoryTreeNode depth guard', () => {
   it('renders depth warning when depth exceeds 10', () => {
     // Build a deeply nested node at depth 11
diff --git a/src/web/src/tests/features/rubros/MoveRubroDialog.test.tsx b/src/web/src/tests/features/rubros/MoveRubroDialog.test.tsx
index 79945cb..85cf2e7 100644
--- a/src/web/src/tests/features/rubros/MoveRubroDialog.test.tsx
+++ b/src/web/src/tests/features/rubros/MoveRubroDialog.test.tsx
@@ -313,6 +313,35 @@ describe('MoveRubroDialog', () => {
     })
   })
 
+  it('displays backend error inline when 409 rubro_padre_es_hoja_con_avisos (CAT-002)', async () => {
+    mockMutateAsync.mockRejectedValue({
+      response: {
+        status: 409,
+        data: {
+          error: 'rubro_padre_es_hoja_con_avisos',
+          message: 'El rubro padre contiene 3 avisos. Muévalos antes de crear sub-rubros.',
+        },
+      },
+    })
+    wrap(
+      <MoveRubroDialog
+        open={true}
+        onOpenChange={vi.fn()}
+        rubro={rubroUsados}
+        tree={fullTree}
+      />,
+    )
+    await waitFor(() => expect(screen.getByRole('dialog')).toBeInTheDocument())
+
+    await userEvent.click(screen.getByRole('button', { name: /mover/i }))
+
+    await waitFor(() => {
+      expect(
+        screen.getByText(/el rubro padre contiene 3 avisos/i),
+      ).toBeInTheDocument()
+    })
+  })
+
   it('displays backend error inline when 422 depth', async () => {
     mockMutateAsync.mockRejectedValue({
       response: {