diff --git a/src/api/SIGCM2.Api/Filters/ExceptionFilter.cs b/src/api/SIGCM2.Api/Filters/ExceptionFilter.cs
index f43eac9..e936231 100644
--- a/src/api/SIGCM2.Api/Filters/ExceptionFilter.cs
+++ b/src/api/SIGCM2.Api/Filters/ExceptionFilter.cs
@@ -242,6 +242,31 @@ public sealed class ExceptionFilter : IExceptionFilter
                 context.ExceptionHandled = true;
                 break;
 
+            // CAT-002: Rubro Regla de Oro (rama vs hoja)
+            case RubroPadreEsHojaConAvisosException rubroPadreHojaEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_padre_es_hoja_con_avisos",
+                    message = rubroPadreHojaEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status409Conflict
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroEsRamaConHijosActivosException rubroRamaHijosEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_es_rama_con_hijos_activos",
+                    message = rubroRamaHijosEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status409Conflict
+                };
+                context.ExceptionHandled = true;
+                break;
+
             // ADM-001: Medio exceptions
             case MedioCodigoDuplicadoException medioCodDupEx:
                 context.Result = new ObjectResult(new
diff --git a/src/api/SIGCM2.Application/Abstractions/Persistence/IAvisoQueryRepository.cs b/src/api/SIGCM2.Application/Abstractions/Persistence/IAvisoQueryRepository.cs
new file mode 100644
index 0000000..a077780
--- /dev/null
+++ b/src/api/SIGCM2.Application/Abstractions/Persistence/IAvisoQueryRepository.cs
@@ -0,0 +1,24 @@
+namespace SIGCM2.Application.Abstractions.Persistence;
+
+/// <summary>
+/// Query-only access to Aviso counts by Rubro.
+/// CAT-002 introduces the contract. The real Dapper-based impl lands in PRD-002
+/// (when dbo.Aviso exists). Until then, NullAvisoQueryRepository is the binding.
+/// </summary>
+public interface IAvisoQueryRepository
+{
+    /// <summary>
+    /// Returns the count of avisos (active, non-archived) assigned to the given rubro.
+    /// </summary>
+    Task<int> CountAvisosEnRubroAsync(int rubroId, CancellationToken ct = default);
+
+    /// <summary>
+    /// Returns a dictionary of { rubroId → count } for the provided ids.
+    /// Used by GetRubroTreeQueryHandler to avoid N+1 when populating TieneAvisos per node.
+    /// The implementation MUST do a single query; the stub returns an empty dictionary
+    /// (every rubro gets 0 via dictionary.GetValueOrDefault).
+    /// </summary>
+    Task<IReadOnlyDictionary<int, int>> CountAvisosBatchAsync(
+        IReadOnlyCollection<int> rubroIds,
+        CancellationToken ct = default);
+}
diff --git a/src/api/SIGCM2.Application/Avisos/NullAvisoQueryRepository.cs b/src/api/SIGCM2.Application/Avisos/NullAvisoQueryRepository.cs
new file mode 100644
index 0000000..223c146
--- /dev/null
+++ b/src/api/SIGCM2.Application/Avisos/NullAvisoQueryRepository.cs
@@ -0,0 +1,22 @@
+using SIGCM2.Application.Abstractions.Persistence;
+
+namespace SIGCM2.Application.Avisos;
+
+/// <summary>
+/// STUB — PRD-002 reemplaza con AvisoQueryRepository contra dbo.Aviso.
+/// Returns 0 / empty dictionary so every handler guard passes and every tree node shows TieneAvisos=false.
+/// This is intentional for CAT-002: the mechanism is installed; the data feed arrives in PRD-002.
+/// </summary>
+public sealed class NullAvisoQueryRepository : IAvisoQueryRepository
+{
+    private static readonly IReadOnlyDictionary<int, int> Empty =
+        new Dictionary<int, int>(capacity: 0);
+
+    public Task<int> CountAvisosEnRubroAsync(int rubroId, CancellationToken ct = default)
+        => Task.FromResult(0);
+
+    public Task<IReadOnlyDictionary<int, int>> CountAvisosBatchAsync(
+        IReadOnlyCollection<int> rubroIds,
+        CancellationToken ct = default)
+        => Task.FromResult(Empty);
+}
diff --git a/src/api/SIGCM2.Application/DependencyInjection.cs b/src/api/SIGCM2.Application/DependencyInjection.cs
index 7d7f85f..2b10fbb 100644
--- a/src/api/SIGCM2.Application/DependencyInjection.cs
+++ b/src/api/SIGCM2.Application/DependencyInjection.cs
@@ -67,6 +67,8 @@ using SIGCM2.Application.Rubros.Move;
 using SIGCM2.Application.Rubros.GetTree;
 using SIGCM2.Application.Rubros.GetById;
 using SIGCM2.Application.Rubros.Dtos;
+using SIGCM2.Application.Abstractions.Persistence;
+using SIGCM2.Application.Avisos;
 
 namespace SIGCM2.Application;
 
@@ -152,7 +154,10 @@ public static class DependencyInjection
         services.AddScoped<ICommandHandler<ListIngresosBrutosQuery, PagedResult<IngresosBrutosDto>>, ListIngresosBrutosQueryHandler>();
         services.AddScoped<ICommandHandler<GetHistorialIngresosBrutosQuery, IReadOnlyList<HistorialCadenaIibbDto>>, GetHistorialIngresosBrutosQueryHandler>();
 
-        // Rubros (CAT-001)
+        // Rubros (CAT-001 + CAT-002)
+        // CAT-002: Regla de Oro Rama vs Hoja — stub binding until PRD-002 provides real impl
+        services.AddScoped<IAvisoQueryRepository, NullAvisoQueryRepository>();
+
         services.AddScoped<ICommandHandler<CreateRubroCommand, RubroCreatedDto>, CreateRubroCommandHandler>();
         services.AddScoped<ICommandHandler<UpdateRubroCommand, RubroUpdatedDto>, UpdateRubroCommandHandler>();
         services.AddScoped<ICommandHandler<DeactivateRubroCommand, RubroStatusDto>, DeactivateRubroCommandHandler>();
diff --git a/src/api/SIGCM2.Application/Rubros/Common/RubroTreeBuilder.cs b/src/api/SIGCM2.Application/Rubros/Common/RubroTreeBuilder.cs
index 3e92ddf..04c3fc0 100644
--- a/src/api/SIGCM2.Application/Rubros/Common/RubroTreeBuilder.cs
+++ b/src/api/SIGCM2.Application/Rubros/Common/RubroTreeBuilder.cs
@@ -12,7 +12,8 @@ public static class RubroTreeBuilder
 {
     public static IReadOnlyList<RubroTreeNodeDto> Build(
         IEnumerable<Rubro> flat,
-        bool incluirInactivos)
+        bool incluirInactivos,
+        IReadOnlyDictionary<int, int> avisoCounts)
     {
         var filtered = incluirInactivos
             ? flat.ToList()
@@ -36,6 +37,7 @@ public static class RubroTreeBuilder
                 Activo: r.Activo,
                 ParentId: r.ParentId,
                 TarifarioBaseId: r.TarifarioBaseId,
+                TieneAvisos: avisoCounts.GetValueOrDefault(r.Id, 0) > 0,
                 Hijos: children);
         }
 
diff --git a/src/api/SIGCM2.Application/Rubros/Create/CreateRubroCommandHandler.cs b/src/api/SIGCM2.Application/Rubros/Create/CreateRubroCommandHandler.cs
index 7332524..f142877 100644
--- a/src/api/SIGCM2.Application/Rubros/Create/CreateRubroCommandHandler.cs
+++ b/src/api/SIGCM2.Application/Rubros/Create/CreateRubroCommandHandler.cs
@@ -14,17 +14,20 @@ public sealed class CreateRubroCommandHandler : ICommandHandler<CreateRubroComma
     private readonly IAuditLogger _audit;
     private readonly TimeProvider _timeProvider;
     private readonly RubrosOptions _options;
+    private readonly IAvisoQueryRepository _avisoQuery;
 
     public CreateRubroCommandHandler(
         IRubroRepository repo,
         IAuditLogger audit,
         TimeProvider timeProvider,
-        IOptions<RubrosOptions> options)
+        IOptions<RubrosOptions> options,
+        IAvisoQueryRepository avisoQuery)
     {
         _repo = repo;
         _audit = audit;
         _timeProvider = timeProvider;
         _options = options.Value;
+        _avisoQuery = avisoQuery;
     }
 
     public async Task<RubroCreatedDto> Handle(CreateRubroCommand command)
@@ -38,6 +41,12 @@ public sealed class CreateRubroCommandHandler : ICommandHandler<CreateRubroComma
             if (!parent.Activo)
                 throw new RubroPadreInactivoException(command.ParentId.Value);
 
+            // CAT-002: Regla de Oro — padre no puede ser hoja con avisos
+            // CAT-002/PRD-002 TOCTOU — evaluar upgrade a RepeatableRead o constraint DB cuando exista dbo.Aviso
+            var avisosCount = await _avisoQuery.CountAvisosEnRubroAsync(command.ParentId.Value);
+            if (avisosCount > 0)
+                throw new RubroPadreEsHojaConAvisosException(command.ParentId.Value, avisosCount);
+
             // Depth check: parent's depth + 1 must not exceed MaxDepth
             var parentDepth = await _repo.GetDepthAsync(command.ParentId);
             var newDepth = parentDepth + 1;
diff --git a/src/api/SIGCM2.Application/Rubros/Dtos/RubroTreeNodeDto.cs b/src/api/SIGCM2.Application/Rubros/Dtos/RubroTreeNodeDto.cs
index 1bf5468..2f4d2c6 100644
--- a/src/api/SIGCM2.Application/Rubros/Dtos/RubroTreeNodeDto.cs
+++ b/src/api/SIGCM2.Application/Rubros/Dtos/RubroTreeNodeDto.cs
@@ -10,4 +10,5 @@ public sealed record RubroTreeNodeDto(
     bool Activo,
     int? ParentId,
     int? TarifarioBaseId,
+    bool TieneAvisos,
     IReadOnlyList<RubroTreeNodeDto> Hijos);
diff --git a/src/api/SIGCM2.Application/Rubros/GetTree/GetRubroTreeQueryHandler.cs b/src/api/SIGCM2.Application/Rubros/GetTree/GetRubroTreeQueryHandler.cs
index 6fcefcc..26e0de1 100644
--- a/src/api/SIGCM2.Application/Rubros/GetTree/GetRubroTreeQueryHandler.cs
+++ b/src/api/SIGCM2.Application/Rubros/GetTree/GetRubroTreeQueryHandler.cs
@@ -8,15 +8,20 @@ namespace SIGCM2.Application.Rubros.GetTree;
 public sealed class GetRubroTreeQueryHandler : ICommandHandler<GetRubroTreeQuery, IReadOnlyList<RubroTreeNodeDto>>
 {
     private readonly IRubroRepository _repo;
+    private readonly IAvisoQueryRepository _avisoQuery;
 
-    public GetRubroTreeQueryHandler(IRubroRepository repo)
+    public GetRubroTreeQueryHandler(IRubroRepository repo, IAvisoQueryRepository avisoQuery)
     {
         _repo = repo;
+        _avisoQuery = avisoQuery;
     }
 
     public async Task<IReadOnlyList<RubroTreeNodeDto>> Handle(GetRubroTreeQuery query)
     {
         var all = await _repo.GetAllAsync(query.IncluirInactivos);
-        return RubroTreeBuilder.Build(all, query.IncluirInactivos);
+        var ids = all.Select(r => r.Id).ToList();
+        // CAT-002: single batch call — avoids N+1 when PRD-002 activates the real implementation
+        var avisoCounts = await _avisoQuery.CountAvisosBatchAsync(ids);
+        return RubroTreeBuilder.Build(all, query.IncluirInactivos, avisoCounts);
     }
 }
diff --git a/src/api/SIGCM2.Application/Rubros/Move/MoveRubroCommandHandler.cs b/src/api/SIGCM2.Application/Rubros/Move/MoveRubroCommandHandler.cs
index 8bd32f5..8adeda7 100644
--- a/src/api/SIGCM2.Application/Rubros/Move/MoveRubroCommandHandler.cs
+++ b/src/api/SIGCM2.Application/Rubros/Move/MoveRubroCommandHandler.cs
@@ -13,17 +13,20 @@ public sealed class MoveRubroCommandHandler : ICommandHandler<MoveRubroCommand,
     private readonly IAuditLogger _audit;
     private readonly TimeProvider _timeProvider;
     private readonly RubrosOptions _options;
+    private readonly IAvisoQueryRepository _avisoQuery;
 
     public MoveRubroCommandHandler(
         IRubroRepository repo,
         IAuditLogger audit,
         TimeProvider timeProvider,
-        IOptions<RubrosOptions> options)
+        IOptions<RubrosOptions> options,
+        IAvisoQueryRepository avisoQuery)
     {
         _repo = repo;
         _audit = audit;
         _timeProvider = timeProvider;
         _options = options.Value;
+        _avisoQuery = avisoQuery;
     }
 
     public async Task<RubroMovedDto> Handle(MoveRubroCommand command)
@@ -47,6 +50,12 @@ public sealed class MoveRubroCommandHandler : ICommandHandler<MoveRubroCommand,
             if (!newParent.Activo)
                 throw new RubroPadreInactivoException(command.NuevoParentId.Value);
 
+            // CAT-002: Regla de Oro — nuevo padre no puede ser hoja con avisos
+            // CAT-002/PRD-002 TOCTOU — evaluar upgrade a RepeatableRead o constraint DB cuando exista dbo.Aviso
+            var avisosCount = await _avisoQuery.CountAvisosEnRubroAsync(command.NuevoParentId.Value);
+            if (avisosCount > 0)
+                throw new RubroPadreEsHojaConAvisosException(command.NuevoParentId.Value, avisosCount);
+
             // Depth check
             var parentDepth = await _repo.GetDepthAsync(command.NuevoParentId);
             var newDepth = parentDepth + 1;
diff --git a/src/api/SIGCM2.Domain/Exceptions/RubroEsRamaConHijosActivosException.cs b/src/api/SIGCM2.Domain/Exceptions/RubroEsRamaConHijosActivosException.cs
new file mode 100644
index 0000000..84bfda6
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/RubroEsRamaConHijosActivosException.cs
@@ -0,0 +1,19 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when attempting to assign an aviso to a rubro that has active children.
+/// Invariante: un nodo con hijos activos es RAMA — no puede recibir avisos directos. → HTTP 409
+/// NOTE: no handler launches this in CAT-002. Consumer: PRD-002 CreateAvisoCommandHandler.
+/// </summary>
+public sealed class RubroEsRamaConHijosActivosException : DomainException
+{
+    public int RubroId { get; }
+    public int CantidadHijos { get; }
+
+    public RubroEsRamaConHijosActivosException(int rubroId, int cantidadHijos)
+        : base($"El destino tiene sub-rubros. No puede contener avisos directos.")
+    {
+        RubroId = rubroId;
+        CantidadHijos = cantidadHijos;
+    }
+}
diff --git a/src/api/SIGCM2.Domain/Exceptions/RubroPadreEsHojaConAvisosException.cs b/src/api/SIGCM2.Domain/Exceptions/RubroPadreEsHojaConAvisosException.cs
new file mode 100644
index 0000000..143e785
--- /dev/null
+++ b/src/api/SIGCM2.Domain/Exceptions/RubroPadreEsHojaConAvisosException.cs
@@ -0,0 +1,18 @@
+namespace SIGCM2.Domain.Exceptions;
+
+/// <summary>
+/// Thrown when attempting to create or move a child into a rubro that already has avisos assigned.
+/// Invariante: un nodo con avisos es HOJA — no puede tener hijos. → HTTP 409
+/// </summary>
+public sealed class RubroPadreEsHojaConAvisosException : DomainException
+{
+    public int ParentId { get; }
+    public int CantidadAvisos { get; }
+
+    public RubroPadreEsHojaConAvisosException(int parentId, int cantidadAvisos)
+        : base($"El rubro padre contiene {cantidadAvisos} avisos. Muévalos antes de crear sub-rubros.")
+    {
+        ParentId = parentId;
+        CantidadAvisos = cantidadAvisos;
+    }
+}
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..8f564b8 100644
--- a/src/web/src/tests/features/rubros/CategoryTree.test.tsx
+++ b/src/web/src/tests/features/rubros/CategoryTree.test.tsx
@@ -110,6 +110,64 @@ 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')).toBe(
+      'El rubro contiene avisos asignados. Muévalos antes de agregar sub-rubros.',
+    )
+  })
+
+  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: {
diff --git a/tests/SIGCM2.Api.Tests/Rubros/RubrosReglaDeOroTests.cs b/tests/SIGCM2.Api.Tests/Rubros/RubrosReglaDeOroTests.cs
new file mode 100644
index 0000000..97e788b
--- /dev/null
+++ b/tests/SIGCM2.Api.Tests/Rubros/RubrosReglaDeOroTests.cs
@@ -0,0 +1,177 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Text.Json;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.Extensions.Logging.Abstractions;
+using SIGCM2.Api.Filters;
+using SIGCM2.Domain.Exceptions;
+using SIGCM2.TestSupport;
+
+namespace SIGCM2.Api.Tests.Rubros;
+
+/// <summary>
+/// CAT-002 — Regla de Oro Rama vs Hoja.
+///
+/// Unit tests: ExceptionFilter mapping for new 409 cases (no DB needed).
+/// Integration: GET /arbol returns tieneAvisos field per node (stub = false).
+///
+/// Design note: the 409 guard behavior is fully covered by unit tests in
+/// SIGCM2.Application.Tests (CreateRubroCommandHandlerTests, MoveRubroCommandHandlerTests).
+/// e2e 409 verification via a separate factory is skipped here because the shared
+/// ApiIntegration singleton factory cannot be safely augmented with per-test DI overrides
+/// (RSA key singleton issue documented in ApiIntegrationCollection.cs).
+/// </summary>
+[Collection("ApiIntegration")]
+public sealed class RubrosReglaDeOroTests : IAsyncLifetime
+{
+    private const string AdminEndpoint = "/api/v1/admin/rubros";
+    private const string ReadEndpoint = "/api/v1/rubros";
+    private const string AdminUsername = "admin";
+    private const string AdminPassword = "@Diego550@";
+
+    private readonly HttpClient _client;
+
+    public RubrosReglaDeOroTests(TestWebAppFactory factory)
+    {
+        _client = factory.CreateClient();
+    }
+
+    public Task InitializeAsync() => Task.CompletedTask;
+    public Task DisposeAsync() => Task.CompletedTask;
+
+    // ── Helpers ───────────────────────────────────────────────────────────────
+
+    private async Task<string> GetAdminTokenAsync()
+    {
+        var response = await _client.PostAsJsonAsync("/api/v1/auth/login", new
+        {
+            username = AdminUsername,
+            password = AdminPassword
+        });
+        response.EnsureSuccessStatusCode();
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        return json.GetProperty("accessToken").GetString()!;
+    }
+
+    private HttpRequestMessage BuildRequest(HttpMethod method, string url, object? body = null, string? bearerToken = null)
+    {
+        var request = new HttpRequestMessage(method, url);
+        if (bearerToken is not null)
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", bearerToken);
+        if (body is not null)
+            request.Content = JsonContent.Create(body);
+        return request;
+    }
+
+    private static async Task DeleteRubroIfExistsAsync(int id)
+    {
+        await using var conn = new Microsoft.Data.SqlClient.SqlConnection(TestConnectionStrings.ApiTestDb);
+        await conn.OpenAsync();
+        await Dapper.SqlMapper.ExecuteAsync(conn, "ALTER TABLE dbo.Rubro SET (SYSTEM_VERSIONING = OFF)");
+        await Dapper.SqlMapper.ExecuteAsync(conn, "DELETE FROM dbo.Rubro_History WHERE Id = @Id", new { Id = id });
+        await Dapper.SqlMapper.ExecuteAsync(conn, """
+            WITH ToDelete AS (
+                SELECT Id FROM dbo.Rubro WHERE Id = @Id
+                UNION ALL
+                SELECT r.Id FROM dbo.Rubro r INNER JOIN ToDelete t ON r.ParentId = t.Id
+            )
+            DELETE r FROM dbo.Rubro r INNER JOIN ToDelete td ON r.Id = td.Id
+            """, new { Id = id });
+        await Dapper.SqlMapper.ExecuteAsync(conn,
+            "ALTER TABLE dbo.Rubro SET (SYSTEM_VERSIONING = ON (HISTORY_TABLE = dbo.Rubro_History, HISTORY_RETENTION_PERIOD = 10 YEARS))");
+    }
+
+    // ── ExceptionFilter unit tests (no DB, no HTTP) ───────────────────────────
+
+    private static ExceptionContext MakeExceptionContext(Exception exception)
+    {
+        var httpContext = new DefaultHttpContext();
+        var routeData = new Microsoft.AspNetCore.Routing.RouteData();
+        var actionDescriptor = new Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor();
+        var modelState = new Microsoft.AspNetCore.Mvc.ModelBinding.ModelStateDictionary();
+        var actionContext = new ActionContext(httpContext, routeData, actionDescriptor, modelState);
+        return new ExceptionContext(actionContext, new List<IFilterMetadata>())
+        {
+            Exception = exception
+        };
+    }
+
+    [Fact]
+    public void ExceptionFilter_MapsRubroPadreEsHojaConAvisos_To409()
+    {
+        var filter = new ExceptionFilter(NullLogger<ExceptionFilter>.Instance);
+        var ctx = MakeExceptionContext(new RubroPadreEsHojaConAvisosException(parentId: 1, cantidadAvisos: 3));
+
+        filter.OnException(ctx);
+
+        var result = Assert.IsType<ObjectResult>(ctx.Result);
+        Assert.Equal(StatusCodes.Status409Conflict, result.StatusCode);
+        var json = System.Text.Json.JsonSerializer.Serialize(result.Value);
+        Assert.Contains("rubro_padre_es_hoja_con_avisos", json);
+    }
+
+    [Fact]
+    public void ExceptionFilter_MapsRubroEsRamaConHijosActivos_To409()
+    {
+        var filter = new ExceptionFilter(NullLogger<ExceptionFilter>.Instance);
+        var ctx = MakeExceptionContext(new RubroEsRamaConHijosActivosException(rubroId: 7, cantidadHijos: 2));
+
+        filter.OnException(ctx);
+
+        var result = Assert.IsType<ObjectResult>(ctx.Result);
+        Assert.Equal(StatusCodes.Status409Conflict, result.StatusCode);
+        var json = System.Text.Json.JsonSerializer.Serialize(result.Value);
+        Assert.Contains("rubro_es_rama_con_hijos_activos", json);
+    }
+
+    // ── Integration: GET /arbol includes tieneAvisos field (stub = false) ─────
+
+    [Fact]
+    public async Task GetTree_ResponseIncludesTieneAvisosField_FalseWithStub()
+    {
+        var token = await GetAdminTokenAsync();
+
+        // Create a root rubro to ensure tree is non-empty
+        using var createReq = BuildRequest(HttpMethod.Post, AdminEndpoint, new
+        {
+            nombre = "TieneAvisosCheck_CAT002",
+            parentId = (int?)null,
+        }, token);
+        var createResp = await _client.SendAsync(createReq);
+        Assert.Equal(HttpStatusCode.Created, createResp.StatusCode);
+        var created = await createResp.Content.ReadFromJsonAsync<JsonElement>();
+        var rootId = created.GetProperty("id").GetInt32();
+
+        try
+        {
+            using var req = BuildRequest(HttpMethod.Get, $"{ReadEndpoint}/tree", bearerToken: token);
+            var resp = await _client.SendAsync(req);
+            Assert.Equal(HttpStatusCode.OK, resp.StatusCode);
+
+            var json = await resp.Content.ReadFromJsonAsync<JsonElement>();
+            var ourNode = json.EnumerateArray()
+                .FirstOrDefault(n => n.GetProperty("id").GetInt32() == rootId);
+
+            Assert.True(ourNode.ValueKind != JsonValueKind.Undefined, "Our rubro must appear in tree");
+            Assert.True(ourNode.TryGetProperty("tieneAvisos", out var tieneAvisos),
+                "tieneAvisos must be present in every tree node (CAT-002 additive field)");
+            Assert.False(tieneAvisos.GetBoolean(),
+                "Stub (NullAvisoQueryRepository) must always return false");
+        }
+        finally
+        {
+            await DeleteRubroIfExistsAsync(rootId);
+        }
+    }
+
+    // ── Integration: POST returns 409 message format (guard path) ─────────────
+    // NOTE: these tests rely on the unit-tested handler behavior. The 409 is proven by:
+    //   - CreateRubroCommandHandlerTests.Handle_ParentTieneAvisos_Throws_RubroPadreEsHojaConAvisosException
+    //   - ExceptionFilter_MapsRubroPadreEsHojaConAvisos_To409 (above)
+    // The combined e2e 409 test is omitted here because it requires per-factory DI override
+    // which conflicts with the shared ApiIntegration RSA singleton pattern.
+    // See: ApiIntegrationCollection.cs for the rationale.
+}
diff --git a/tests/SIGCM2.Application.Tests/Avisos/NullAvisoQueryRepositoryTests.cs b/tests/SIGCM2.Application.Tests/Avisos/NullAvisoQueryRepositoryTests.cs
new file mode 100644
index 0000000..4afa33d
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Avisos/NullAvisoQueryRepositoryTests.cs
@@ -0,0 +1,35 @@
+using FluentAssertions;
+using SIGCM2.Application.Avisos;
+
+namespace SIGCM2.Application.Tests.Avisos;
+
+public class NullAvisoQueryRepositoryTests
+{
+    private readonly NullAvisoQueryRepository _repo = new();
+
+    [Fact]
+    public async Task CountAvisosEnRubroAsync_Always_ReturnsZero()
+    {
+        var result = await _repo.CountAvisosEnRubroAsync(rubroId: 99);
+
+        result.Should().Be(0);
+    }
+
+    [Fact]
+    public async Task CountAvisosBatchAsync_WithIds_ReturnsDictionaryAllZero()
+    {
+        var result = await _repo.CountAvisosBatchAsync([1, 2, 3]);
+
+        result.GetValueOrDefault(1, 0).Should().Be(0);
+        result.GetValueOrDefault(2, 0).Should().Be(0);
+        result.GetValueOrDefault(3, 0).Should().Be(0);
+    }
+
+    [Fact]
+    public async Task CountAvisosBatchAsync_EmptyIds_ReturnsEmptyDictionary()
+    {
+        var result = await _repo.CountAvisosBatchAsync([]);
+
+        result.Should().HaveCount(0);
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Domain/Rubros/RubroReglaDeOroExceptionsTests.cs b/tests/SIGCM2.Application.Tests/Domain/Rubros/RubroReglaDeOroExceptionsTests.cs
new file mode 100644
index 0000000..6327d5b
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Domain/Rubros/RubroReglaDeOroExceptionsTests.cs
@@ -0,0 +1,61 @@
+using FluentAssertions;
+using SIGCM2.Domain.Exceptions;
+
+namespace SIGCM2.Application.Tests.Domain.Rubros;
+
+public class RubroReglaDeOroExceptionsTests
+{
+    // ── RubroPadreEsHojaConAvisosException ──────────────────────────────────
+
+    [Fact]
+    public void RubroPadreEsHojaConAvisosException_Constructor_SetsMessage()
+    {
+        var ex = new RubroPadreEsHojaConAvisosException(parentId: 42, cantidadAvisos: 3);
+
+        ex.Message.Should().Be("El rubro padre contiene 3 avisos. Muévalos antes de crear sub-rubros.");
+    }
+
+    [Fact]
+    public void RubroPadreEsHojaConAvisosException_Constructor_SetsParentId_Y_CantidadAvisos()
+    {
+        var ex = new RubroPadreEsHojaConAvisosException(parentId: 42, cantidadAvisos: 3);
+
+        ex.ParentId.Should().Be(42);
+        ex.CantidadAvisos.Should().Be(3);
+    }
+
+    [Fact]
+    public void RubroPadreEsHojaConAvisosException_IsA_DomainException()
+    {
+        var ex = new RubroPadreEsHojaConAvisosException(parentId: 1, cantidadAvisos: 1);
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+
+    // ── RubroEsRamaConHijosActivosException ─────────────────────────────────
+
+    [Fact]
+    public void RubroEsRamaConHijosActivosException_Constructor_SetsMessage()
+    {
+        var ex = new RubroEsRamaConHijosActivosException(rubroId: 7, cantidadHijos: 2);
+
+        ex.Message.Should().Be("El destino tiene sub-rubros. No puede contener avisos directos.");
+    }
+
+    [Fact]
+    public void RubroEsRamaConHijosActivosException_Constructor_SetsRubroId_Y_CantidadHijos()
+    {
+        var ex = new RubroEsRamaConHijosActivosException(rubroId: 7, cantidadHijos: 2);
+
+        ex.RubroId.Should().Be(7);
+        ex.CantidadHijos.Should().Be(2);
+    }
+
+    [Fact]
+    public void RubroEsRamaConHijosActivosException_IsA_DomainException()
+    {
+        var ex = new RubroEsRamaConHijosActivosException(rubroId: 1, cantidadHijos: 1);
+
+        ex.Should().BeAssignableTo<DomainException>();
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Rubros/Create/CreateRubroCommandHandlerTests.cs b/tests/SIGCM2.Application.Tests/Rubros/Create/CreateRubroCommandHandlerTests.cs
index f4b4798..6181380 100644
--- a/tests/SIGCM2.Application.Tests/Rubros/Create/CreateRubroCommandHandlerTests.cs
+++ b/tests/SIGCM2.Application.Tests/Rubros/Create/CreateRubroCommandHandlerTests.cs
@@ -18,6 +18,7 @@ public class CreateRubroCommandHandlerTests
     private readonly IAuditLogger _audit = Substitute.For<IAuditLogger>();
     private readonly FakeTimeProvider _timeProvider = new(new DateTimeOffset(2026, 4, 18, 12, 0, 0, TimeSpan.Zero));
     private readonly IOptions<RubrosOptions> _options = Options.Create(new RubrosOptions { MaxDepth = 10 });
+    private readonly IAvisoQueryRepository _avisoQuery = Substitute.For<IAvisoQueryRepository>();
     private readonly CreateRubroCommandHandler _handler;
 
     public CreateRubroCommandHandlerTests()
@@ -30,8 +31,11 @@ public class CreateRubroCommandHandlerTests
              .Returns(1);
         _repo.GetDepthAsync(Arg.Any<int?>(), Arg.Any<CancellationToken>())
              .Returns(0);
+        // Default: no avisos (stub behavior)
+        _avisoQuery.CountAvisosEnRubroAsync(Arg.Any<int>(), Arg.Any<CancellationToken>())
+                   .Returns(0);
 
-        _handler = new CreateRubroCommandHandler(_repo, _audit, _timeProvider, _options);
+        _handler = new CreateRubroCommandHandler(_repo, _audit, _timeProvider, _options, _avisoQuery);
     }
 
     private static CreateRubroCommand RootCommand() => new("Autos", ParentId: null, TarifarioBaseId: null);
@@ -173,4 +177,76 @@ public class CreateRubroCommandHandlerTests
 
         result.Id.Should().Be(99);
     }
+
+    // ── CAT-002: Guard padre sin avisos ──────────────────────────────────────
+
+    [Fact]
+    public async Task Handle_ParentTieneAvisos_Throws_RubroPadreEsHojaConAvisosException()
+    {
+        const int parentId = 5;
+        var parent = new Rubro(parentId, null, "ParentConAvisos", 0, activo: true, tarifarioBaseId: null,
+            fechaCreacion: DateTime.UtcNow, fechaModificacion: null);
+        _repo.GetByIdAsync(parentId, Arg.Any<CancellationToken>()).Returns(parent);
+        _avisoQuery.CountAvisosEnRubroAsync(parentId, Arg.Any<CancellationToken>()).Returns(3);
+
+        var act = () => _handler.Handle(ChildCommand(parentId: parentId));
+
+        await act.Should().ThrowAsync<RubroPadreEsHojaConAvisosException>()
+            .Where(ex => ex.ParentId == parentId && ex.CantidadAvisos == 3);
+    }
+
+    [Fact]
+    public async Task Handle_ParentTieneCeroAvisos_DoesNotThrow()
+    {
+        const int parentId = 5;
+        var parent = new Rubro(parentId, null, "ParentSinAvisos", 0, activo: true, tarifarioBaseId: null,
+            fechaCreacion: DateTime.UtcNow, fechaModificacion: null);
+        _repo.GetByIdAsync(parentId, Arg.Any<CancellationToken>()).Returns(parent);
+        _avisoQuery.CountAvisosEnRubroAsync(parentId, Arg.Any<CancellationToken>()).Returns(0);
+        _repo.AddAsync(Arg.Any<Rubro>(), Arg.Any<CancellationToken>()).Returns(10);
+
+        var result = await _handler.Handle(ChildCommand(parentId: parentId));
+
+        result.Id.Should().Be(10);
+    }
+
+    [Fact]
+    public async Task Handle_ParentNull_SkipsAvisosGuard()
+    {
+        // Root creation — no parent → CountAvisosEnRubroAsync should NOT be called
+        await _handler.Handle(RootCommand());
+
+        await _avisoQuery.DidNotReceive().CountAvisosEnRubroAsync(Arg.Any<int>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_GuardOrder_ParentInactivo_Wins_OverAvisos()
+    {
+        // Inactive parent with avisos → RubroPadreInactivoException (not avisos exception)
+        const int parentId = 7;
+        var inactiveParent = new Rubro(parentId, null, "InactivoConAvisos", 0, activo: false, tarifarioBaseId: null,
+            fechaCreacion: DateTime.UtcNow, fechaModificacion: null);
+        _repo.GetByIdAsync(parentId, Arg.Any<CancellationToken>()).Returns(inactiveParent);
+        _avisoQuery.CountAvisosEnRubroAsync(parentId, Arg.Any<CancellationToken>()).Returns(3);
+
+        var act = () => _handler.Handle(ChildCommand(parentId: parentId));
+
+        await act.Should().ThrowAsync<RubroPadreInactivoException>();
+    }
+
+    [Fact]
+    public async Task Handle_GuardOrder_Avisos_Wins_OverDepth()
+    {
+        // Parent at MAX_DEPTH AND has avisos → RubroPadreEsHojaConAvisosException (avisos guard fires first)
+        const int parentId = 5;
+        var parent = new Rubro(parentId, null, "ParentAtMaxDepth", 0, activo: true, tarifarioBaseId: null,
+            fechaCreacion: DateTime.UtcNow, fechaModificacion: null);
+        _repo.GetByIdAsync(parentId, Arg.Any<CancellationToken>()).Returns(parent);
+        _avisoQuery.CountAvisosEnRubroAsync(parentId, Arg.Any<CancellationToken>()).Returns(2);
+        _repo.GetDepthAsync(parentId, Arg.Any<CancellationToken>()).Returns(10); // at MaxDepth
+
+        var act = () => _handler.Handle(ChildCommand(parentId: parentId));
+
+        await act.Should().ThrowAsync<RubroPadreEsHojaConAvisosException>();
+    }
 }
diff --git a/tests/SIGCM2.Application.Tests/Rubros/GetTree/GetRubroTreeQueryHandlerTests.cs b/tests/SIGCM2.Application.Tests/Rubros/GetTree/GetRubroTreeQueryHandlerTests.cs
index e79edbb..00e4150 100644
--- a/tests/SIGCM2.Application.Tests/Rubros/GetTree/GetRubroTreeQueryHandlerTests.cs
+++ b/tests/SIGCM2.Application.Tests/Rubros/GetTree/GetRubroTreeQueryHandlerTests.cs
@@ -2,6 +2,7 @@ using FluentAssertions;
 using Microsoft.Extensions.Time.Testing;
 using NSubstitute;
 using SIGCM2.Application.Abstractions.Persistence;
+using SIGCM2.Application.Avisos;
 using SIGCM2.Application.Rubros.GetById;
 using SIGCM2.Application.Rubros.GetTree;
 using SIGCM2.Domain.Entities;
@@ -13,6 +14,7 @@ public class GetRubroTreeQueryHandlerTests
 {
     private static readonly FakeTimeProvider FakeTime = new(new DateTimeOffset(2026, 4, 18, 12, 0, 0, TimeSpan.Zero));
     private readonly IRubroRepository _repo = Substitute.For<IRubroRepository>();
+    private readonly IAvisoQueryRepository _avisoQuery = Substitute.For<IAvisoQueryRepository>();
 
     private static Rubro MakeRubro(int id, int? parentId = null, bool activo = true)
         => new(id, parentId, $"Rubro{id}", 0, activo, null, FakeTime.GetUtcNow().UtcDateTime, null);
@@ -24,8 +26,10 @@ public class GetRubroTreeQueryHandlerTests
     {
         _repo.GetAllAsync(false, Arg.Any<CancellationToken>())
              .Returns(new[] { MakeRubro(1), MakeRubro(2) });
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int>());
 
-        var handler = new GetRubroTreeQueryHandler(_repo);
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
         var result = await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
 
         result.Should().HaveCount(2);
@@ -36,8 +40,10 @@ public class GetRubroTreeQueryHandlerTests
     {
         _repo.GetAllAsync(true, Arg.Any<CancellationToken>())
              .Returns(new[] { MakeRubro(1), MakeRubro(2, activo: false) });
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int>());
 
-        var handler = new GetRubroTreeQueryHandler(_repo);
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
         var result = await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: true));
 
         await _repo.Received(1).GetAllAsync(true, Arg.Any<CancellationToken>());
@@ -49,13 +55,77 @@ public class GetRubroTreeQueryHandlerTests
     {
         _repo.GetAllAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
              .Returns(Array.Empty<Rubro>());
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int>());
 
-        var handler = new GetRubroTreeQueryHandler(_repo);
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
         var result = await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
 
         result.Should().BeEmpty();
     }
 
+    // ── CAT-002: TieneAvisos populated via batch ─────────────────────────────
+
+    [Fact]
+    public async Task Handle_PopulatesTieneAvisos_True_WhenBatchResultContainsCount()
+    {
+        _repo.GetAllAsync(false, Arg.Any<CancellationToken>())
+             .Returns(new[] { MakeRubro(1), MakeRubro(2), MakeRubro(3) });
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int> { { 1, 2 } });
+
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
+        var result = await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
+
+        result.Single(n => n.Id == 1).TieneAvisos.Should().BeTrue();
+        result.Single(n => n.Id == 2).TieneAvisos.Should().BeFalse();
+        result.Single(n => n.Id == 3).TieneAvisos.Should().BeFalse();
+    }
+
+    [Fact]
+    public async Task Handle_CallsBatchExactlyOnce_WithAllRubroIds()
+    {
+        _repo.GetAllAsync(false, Arg.Any<CancellationToken>())
+             .Returns(new[] { MakeRubro(1), MakeRubro(2), MakeRubro(3) });
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int>());
+
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
+        await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
+
+        await _avisoQuery.Received(1).CountAvisosBatchAsync(
+            Arg.Any<IReadOnlyCollection<int>>(),
+            Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_EmptyTree_CallsBatchWithEmptyList()
+    {
+        _repo.GetAllAsync(Arg.Any<bool>(), Arg.Any<CancellationToken>())
+             .Returns(Array.Empty<Rubro>());
+        _avisoQuery.CountAvisosBatchAsync(Arg.Any<IReadOnlyCollection<int>>(), Arg.Any<CancellationToken>())
+                   .Returns(new Dictionary<int, int>());
+
+        var handler = new GetRubroTreeQueryHandler(_repo, _avisoQuery);
+        await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
+
+        await _avisoQuery.Received(1).CountAvisosBatchAsync(
+            Arg.Is<IReadOnlyCollection<int>>(ids => ids.Count == 0),
+            Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_StubBehavior_AllNodesTieneAvisosFalse()
+    {
+        _repo.GetAllAsync(false, Arg.Any<CancellationToken>())
+             .Returns(new[] { MakeRubro(1), MakeRubro(2) });
+
+        var handler = new GetRubroTreeQueryHandler(_repo, new NullAvisoQueryRepository());
+        var result = await handler.Handle(new GetRubroTreeQuery(IncluirInactivos: false));
+
+        result.Should().AllSatisfy(n => n.TieneAvisos.Should().BeFalse());
+    }
+
     // ── GetRubroByIdQueryHandler ─────────────────────────────────────────────
 
     [Fact]
diff --git a/tests/SIGCM2.Application.Tests/Rubros/Move/MoveRubroCommandHandlerTests.cs b/tests/SIGCM2.Application.Tests/Rubros/Move/MoveRubroCommandHandlerTests.cs
index 51bea63..9f4046c 100644
--- a/tests/SIGCM2.Application.Tests/Rubros/Move/MoveRubroCommandHandlerTests.cs
+++ b/tests/SIGCM2.Application.Tests/Rubros/Move/MoveRubroCommandHandlerTests.cs
@@ -17,6 +17,7 @@ public class MoveRubroCommandHandlerTests
     private readonly IAuditLogger _audit = Substitute.For<IAuditLogger>();
     private readonly FakeTimeProvider _timeProvider = new(new DateTimeOffset(2026, 4, 18, 12, 0, 0, TimeSpan.Zero));
     private readonly IOptions<RubrosOptions> _options = Options.Create(new RubrosOptions { MaxDepth = 10 });
+    private readonly IAvisoQueryRepository _avisoQuery = Substitute.For<IAvisoQueryRepository>();
     private readonly MoveRubroCommandHandler _handler;
 
     private static Rubro MakeRubro(int id, int? parentId = null, bool activo = true)
@@ -32,8 +33,11 @@ public class MoveRubroCommandHandlerTests
              .Returns(0);
         _repo.GetMaxOrdenAsync(Arg.Any<int?>(), Arg.Any<CancellationToken>())
              .Returns(0);
+        // Default: no avisos
+        _avisoQuery.CountAvisosEnRubroAsync(Arg.Any<int>(), Arg.Any<CancellationToken>())
+                   .Returns(0);
 
-        _handler = new MoveRubroCommandHandler(_repo, _audit, _timeProvider, _options);
+        _handler = new MoveRubroCommandHandler(_repo, _audit, _timeProvider, _options, _avisoQuery);
     }
 
     // ── Happy path: move to other parent ────────────────────────────────────
@@ -173,4 +177,66 @@ public class MoveRubroCommandHandlerTests
 
         await act.Should().ThrowAsync<RubroMaxDepthExceededException>();
     }
+
+    // ── CAT-002: Guard nuevo padre sin avisos ───────────────────────────────
+
+    [Fact]
+    public async Task Handle_NuevoParentTieneAvisos_Throws_RubroPadreEsHojaConAvisosException()
+    {
+        const int nuevoParentId = 20;
+        var rubro = MakeRubro(8, parentId: 2);
+        var newParent = MakeRubro(nuevoParentId);
+        _repo.GetByIdAsync(8, Arg.Any<CancellationToken>()).Returns(rubro);
+        _repo.GetByIdAsync(nuevoParentId, Arg.Any<CancellationToken>()).Returns(newParent);
+        _avisoQuery.CountAvisosEnRubroAsync(nuevoParentId, Arg.Any<CancellationToken>()).Returns(2);
+
+        var act = () => _handler.Handle(new MoveRubroCommand(Id: 8, NuevoParentId: nuevoParentId, NuevoOrden: 0));
+
+        await act.Should().ThrowAsync<RubroPadreEsHojaConAvisosException>()
+            .Where(ex => ex.ParentId == nuevoParentId && ex.CantidadAvisos == 2);
+    }
+
+    [Fact]
+    public async Task Handle_NuevoParentTieneCeroAvisos_DoesNotThrow()
+    {
+        const int nuevoParentId = 20;
+        var rubro = MakeRubro(8, parentId: 2);
+        var newParent = MakeRubro(nuevoParentId);
+        _repo.GetByIdAsync(8, Arg.Any<CancellationToken>()).Returns(rubro);
+        _repo.GetByIdAsync(nuevoParentId, Arg.Any<CancellationToken>()).Returns(newParent);
+        _avisoQuery.CountAvisosEnRubroAsync(nuevoParentId, Arg.Any<CancellationToken>()).Returns(0);
+
+        var result = await _handler.Handle(new MoveRubroCommand(Id: 8, NuevoParentId: nuevoParentId, NuevoOrden: 0));
+
+        result.Id.Should().Be(8);
+    }
+
+    [Fact]
+    public async Task Handle_NuevoParentEsNull_SkipsAvisosGuard()
+    {
+        // Move to root — no parent to check avisos for
+        var rubro = MakeRubro(8, parentId: 2);
+        _repo.GetByIdAsync(8, Arg.Any<CancellationToken>()).Returns(rubro);
+
+        await _handler.Handle(new MoveRubroCommand(Id: 8, NuevoParentId: null, NuevoOrden: 0));
+
+        await _avisoQuery.DidNotReceive().CountAvisosEnRubroAsync(Arg.Any<int>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_CycleCheck_Wins_OverAvisosGuard()
+    {
+        // Cycle check fires before avisos guard
+        const int nuevoParentId = 10;
+        var rubro = MakeRubro(5, parentId: null);
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(rubro);
+        // nuevoParentId IS a descendant (cycle)
+        _repo.GetDescendantsAsync(5, Arg.Any<CancellationToken>())
+             .Returns(new[] { MakeRubro(nuevoParentId, parentId: 5) });
+        _avisoQuery.CountAvisosEnRubroAsync(nuevoParentId, Arg.Any<CancellationToken>()).Returns(3);
+
+        var act = () => _handler.Handle(new MoveRubroCommand(Id: 5, NuevoParentId: nuevoParentId, NuevoOrden: 0));
+
+        await act.Should().ThrowAsync<RubroCycleDetectedException>();
+    }
 }
diff --git a/tests/SIGCM2.Application.Tests/Rubros/RubroTreeBuilderTests.cs b/tests/SIGCM2.Application.Tests/Rubros/RubroTreeBuilderTests.cs
index 14e8338..c56aa9a 100644
--- a/tests/SIGCM2.Application.Tests/Rubros/RubroTreeBuilderTests.cs
+++ b/tests/SIGCM2.Application.Tests/Rubros/RubroTreeBuilderTests.cs
@@ -18,7 +18,7 @@ public class RubroTreeBuilderTests
     [Fact]
     public void Build_empty_returns_empty_list()
     {
-        var result = RubroTreeBuilder.Build([], incluirInactivos: false);
+        var result = RubroTreeBuilder.Build([], incluirInactivos: false, new Dictionary<int, int>());
 
         result.Should().BeEmpty();
     }
@@ -30,7 +30,7 @@ public class RubroTreeBuilderTests
     {
         var rubros = new[] { MakeRubro(1, null, "Autos", 0) };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
 
         result.Should().HaveCount(1);
         result[0].Id.Should().Be(1);
@@ -50,7 +50,7 @@ public class RubroTreeBuilderTests
             MakeRubro(2, null, "Camiones", 1)
         };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
 
         result.Should().HaveCount(3);
         result[0].Id.Should().Be(1); // Orden=0
@@ -70,7 +70,7 @@ public class RubroTreeBuilderTests
             MakeRubro(3, 2, "Compactos", 0),
         };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
 
         result.Should().HaveCount(1);
         result[0].Id.Should().Be(1);
@@ -91,7 +91,7 @@ public class RubroTreeBuilderTests
             MakeRubro(2, null, "Motos", 1, activo: false),
         };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
 
         result.Should().HaveCount(1);
         result[0].Id.Should().Be(1);
@@ -106,7 +106,7 @@ public class RubroTreeBuilderTests
             MakeRubro(2, null, "Motos", 1, activo: false),
         };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: true);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: true, new Dictionary<int, int>());
 
         result.Should().HaveCount(2);
     }
@@ -125,7 +125,7 @@ public class RubroTreeBuilderTests
             MakeRubro(5, 1, "A", 0),
         };
 
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
 
         var hijos = result[0].Hijos;
         hijos.Should().HaveCount(4);
@@ -135,6 +135,47 @@ public class RubroTreeBuilderTests
         hijos[3].Nombre.Should().Be("D"); // Orden=3
     }
 
+    // ── TieneAvisos from avisoCounts dict ────────────────────────────────────
+
+    [Fact]
+    public void Build_SetsTieneAvisos_True_WhenCountGreaterThanZero()
+    {
+        var rubros = new[]
+        {
+            MakeRubro(1, null, "Autos", 0),
+            MakeRubro(2, null, "Motos", 1),
+        };
+        var avisoCounts = new Dictionary<int, int> { { 1, 2 }, { 2, 0 } };
+
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, avisoCounts);
+
+        result.Single(n => n.Id == 1).TieneAvisos.Should().BeTrue();
+        result.Single(n => n.Id == 2).TieneAvisos.Should().BeFalse();
+    }
+
+    [Fact]
+    public void Build_SetsTieneAvisos_False_WhenCountIsZero()
+    {
+        var rubros = new[] { MakeRubro(1, null, "Autos", 0) };
+        var avisoCounts = new Dictionary<int, int> { { 1, 0 } };
+
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, avisoCounts);
+
+        result[0].TieneAvisos.Should().BeFalse();
+    }
+
+    [Fact]
+    public void Build_SetsTieneAvisos_False_WhenIdMissingFromDict()
+    {
+        // Stub semantics: missing key = 0 = false
+        var rubros = new[] { MakeRubro(1, null, "Autos", 0) };
+        var avisoCounts = new Dictionary<int, int>(); // empty dict
+
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, avisoCounts);
+
+        result[0].TieneAvisos.Should().BeFalse();
+    }
+
     // ── O(n) perf smoke test ──────────────────────────────────────────────────
 
     [Fact]
@@ -148,7 +189,7 @@ public class RubroTreeBuilderTests
             rubros.Add(MakeRubro(i, 1, $"Child{i}", i - 2));
 
         var sw = System.Diagnostics.Stopwatch.StartNew();
-        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false);
+        var result = RubroTreeBuilder.Build(rubros, incluirInactivos: false, new Dictionary<int, int>());
         sw.Stop();
 
         result.Should().HaveCount(1);