diff --git a/src/ClaudeDo.Worker/External/ListMcpTools.cs b/src/ClaudeDo.Worker/External/ListMcpTools.cs
index d1884e7..15479a8 100644
--- a/src/ClaudeDo.Worker/External/ListMcpTools.cs
+++ b/src/ClaudeDo.Worker/External/ListMcpTools.cs
@@ -47,6 +47,8 @@ public sealed class ListMcpTools
         var entity = await _lists.GetByIdAsync(listId, cancellationToken)
             ?? throw new InvalidOperationException($"List {listId} not found.");
 
+        if (name is not null && string.IsNullOrWhiteSpace(name))
+            throw new InvalidOperationException("name cannot be blank.");
         if (name is not null) entity.Name = name;
         if (workingDir is not null)
             entity.WorkingDir = string.IsNullOrWhiteSpace(workingDir) ? null : workingDir;
diff --git a/tests/ClaudeDo.Worker.Tests/External/ListMcpToolsTests.cs b/tests/ClaudeDo.Worker.Tests/External/ListMcpToolsTests.cs
index 9f096d1..50f1f05 100644
--- a/tests/ClaudeDo.Worker.Tests/External/ListMcpToolsTests.cs
+++ b/tests/ClaudeDo.Worker.Tests/External/ListMcpToolsTests.cs
@@ -4,34 +4,9 @@ using ClaudeDo.Data.Repositories;
 using ClaudeDo.Worker.External;
 using ClaudeDo.Worker.Hub;
 using ClaudeDo.Worker.Tests.Infrastructure;
-using Microsoft.AspNetCore.SignalR;
 
 namespace ClaudeDo.Worker.Tests.External;
 
-internal sealed class ListToolsHubClients : IHubClients
-{
-    public ListToolsClientProxy Proxy { get; } = new();
-    public IClientProxy All => Proxy;
-    public IClientProxy AllExcept(IReadOnlyList<string> e) => Proxy;
-    public IClientProxy Client(string c) => Proxy;
-    public IClientProxy Clients(IReadOnlyList<string> c) => Proxy;
-    public IClientProxy Group(string g) => Proxy;
-    public IClientProxy GroupExcept(string g, IReadOnlyList<string> e) => Proxy;
-    public IClientProxy Groups(IReadOnlyList<string> g) => Proxy;
-    public IClientProxy User(string u) => Proxy;
-    public IClientProxy Users(IReadOnlyList<string> u) => Proxy;
-}
-internal sealed class ListToolsClientProxy : IClientProxy
-{
-    public Task SendCoreAsync(string m, object?[] a, CancellationToken ct = default) => Task.CompletedTask;
-}
-internal sealed class ListToolsHubContext : IHubContext<WorkerHub>
-{
-    public ListToolsHubClients RecordingClients { get; } = new();
-    public IHubClients Clients => RecordingClients;
-    public IGroupManager Groups => throw new NotImplementedException();
-}
-
 public sealed class ListMcpToolsTests : IDisposable
 {
     private readonly DbFixture _db = new();
@@ -43,7 +18,7 @@ public sealed class ListMcpToolsTests : IDisposable
     {
         _ctx = _db.CreateContext();
         _lists = new ListRepository(_ctx);
-        _sut = new ListMcpTools(_lists, new HubBroadcaster(new ListToolsHubContext()));
+        _sut = new ListMcpTools(_lists, new HubBroadcaster(new CapturingHubContext()));
     }
 
     public void Dispose() { _ctx.Dispose(); _db.Dispose(); }