test(data,worker): cover ExpectsNoDiff persistence and MCP wiring

Data.Tests: default-false and true-roundtrip on TaskEntity.
Worker.Tests: add_task/update_task set/clear/leave-unchanged, and
preview_merge_set surfaces the flag per task.

tests/ClaudeDo.Data.Tests/ExpectsNoDiffTests.cs

@@ -0,0 +1,58 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using Microsoft.EntityFrameworkCore;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Tests;
+
+public sealed class ExpectsNoDiffTests : IDisposable
+{
+    private readonly string _dbPath;
+    private readonly ClaudeDoDbContext _ctx;
+
+    private const string ListId = "l1";
+
+    public ExpectsNoDiffTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_endiff_{Guid.NewGuid():N}.db");
+        var options = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"Data Source={_dbPath}")
+            .Options;
+        _ctx = new ClaudeDoDbContext(options);
+        _ctx.Database.EnsureCreated();
+
+        _ctx.Lists.Add(new ListEntity { Id = ListId, Name = "Test", CreatedAt = DateTime.UtcNow });
+        _ctx.SaveChanges();
+    }
+
+    public void Dispose()
+    {
+        _ctx.Dispose();
+        foreach (var suffix in new[] { "", "-wal", "-shm" })
+            try { File.Delete(_dbPath + suffix); } catch { }
+    }
+
+    [Fact]
+    public void DefaultsToFalse_WhenNotSet()
+    {
+        var task = new TaskEntity { Id = "t1", ListId = ListId, Title = "T", Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow };
+        _ctx.Tasks.Add(task);
+        _ctx.SaveChanges();
+
+        using var reload = new ClaudeDoDbContext(new DbContextOptionsBuilder<ClaudeDoDbContext>().UseSqlite(_ctx.Database.GetConnectionString()).Options);
+        var reloaded = reload.Tasks.Single(t => t.Id == "t1");
+        Assert.False(reloaded.ExpectsNoDiff);
+    }
+
+    [Fact]
+    public void PersistsTrue_Roundtrip()
+    {
+        var task = new TaskEntity { Id = "t2", ListId = ListId, Title = "T", Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow, ExpectsNoDiff = true };
+        _ctx.Tasks.Add(task);
+        _ctx.SaveChanges();
+
+        using var reload = new ClaudeDoDbContext(new DbContextOptionsBuilder<ClaudeDoDbContext>().UseSqlite(_ctx.Database.GetConnectionString()).Options);
+        var reloaded = reload.Tasks.Single(t => t.Id == "t2");
+        Assert.True(reloaded.ExpectsNoDiff);
+    }
+}

tests/ClaudeDo.Worker.Tests/External/ExternalMcpServiceTests.cs

@@ -272,6 +272,50 @@ public sealed class ExternalMcpServiceTests : IDisposable
         Assert.True(dto.IsManual);
     }
 
+    [Fact]
+    public async Task UpdateTask_SetsExpectsNoDiffTrue()
+    {
+        var listId = await SeedListAsync();
+        var task = await SeedTaskAsync(listId);
+        var sut = BuildSut(CreateQueue());
+
+        var dto = await sut.UpdateTask(task.Id, expectsNoDiff: true, cancellationToken: CancellationToken.None);
+
+        Assert.True(dto.ExpectsNoDiff);
+        var loaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.True(loaded!.ExpectsNoDiff);
+    }
+
+    [Fact]
+    public async Task UpdateTask_SetsExpectsNoDiffFalse_ClearsExistingFlag()
+    {
+        var listId = await SeedListAsync();
+        var task = await SeedTaskAsync(listId);
+        task.ExpectsNoDiff = true;
+        await _tasks.UpdateAsync(task, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+
+        var dto = await sut.UpdateTask(task.Id, expectsNoDiff: false, cancellationToken: CancellationToken.None);
+
+        Assert.False(dto.ExpectsNoDiff);
+        var loaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.False(loaded!.ExpectsNoDiff);
+    }
+
+    [Fact]
+    public async Task UpdateTask_ExpectsNoDiffNull_LeavesUnchanged()
+    {
+        var listId = await SeedListAsync();
+        var task = await SeedTaskAsync(listId);
+        task.ExpectsNoDiff = true;
+        await _tasks.UpdateAsync(task, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+
+        var dto = await sut.UpdateTask(task.Id, title: "new title", cancellationToken: CancellationToken.None);
+
+        Assert.True(dto.ExpectsNoDiff);
+    }
+
     [Fact]
     public async Task GetTask_ReturnsTaskNumber()
     {
@@ -2653,6 +2697,22 @@ public sealed class ExternalMcpServiceTests : IDisposable
         Assert.Empty(result.Overlaps);
     }
 
+    [Fact]
+    public async Task PreviewMergeSet_ReportsExpectsNoDiffPerTask()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, list, _) = await SeedWorktreeAsync(TaskStatus.WaitingForReview);
+        task.ExpectsNoDiff = true;
+        await _tasks.UpdateAsync(task, CancellationToken.None);
+        var target = await new GitService().GetCurrentBranchAsync(list.WorkingDir!, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+
+        var result = await sut.PreviewMergeSet([task.Id], target, cancellationToken: CancellationToken.None);
+
+        Assert.True(Assert.Single(result.Tasks).ExpectsNoDiff);
+    }
+
     [Fact]
     public async Task PreviewMergeSet_ReportsProgressPerTask()
     {
@@ -2801,6 +2861,32 @@ public sealed class ExternalMcpServiceTests : IDisposable
         Assert.Equal(loaded!.Number, dto.Task.Number);
     }
 
+    [Fact]
+    public async Task AddTask_DefaultExpectsNoDiff_IsFalse()
+    {
+        var listId = await SeedListAsync();
+        var sut = NewService();
+
+        var dto = await sut.AddTask(listId, "t", cancellationToken: CancellationToken.None);
+
+        Assert.False(dto.Task.ExpectsNoDiff);
+        var loaded = await _tasks.GetByIdAsync(dto.Task.Id);
+        Assert.False(loaded!.ExpectsNoDiff);
+    }
+
+    [Fact]
+    public async Task AddTask_ExpectsNoDiffTrue_PersistsFlag()
+    {
+        var listId = await SeedListAsync();
+        var sut = NewService();
+
+        var dto = await sut.AddTask(listId, "t", expectsNoDiff: true, cancellationToken: CancellationToken.None);
+
+        Assert.True(dto.Task.ExpectsNoDiff);
+        var loaded = await _tasks.GetByIdAsync(dto.Task.Id);
+        Assert.True(loaded!.ExpectsNoDiff);
+    }
+
     // ── AddTask model override ────────────────────────────────────────────────
 
     [Fact]