feat(planning): let CreateChildTask set maxTurns on child tasks

Planning sessions could already steer a subtask's model but not its turn
budget, so a visibly large subtask would still die at the global default
turn limit. maxTurns is optional (default null = inherit list/global
default, matching model); 0/negative values are rejected as invalid input,
consistent with the existing model-alias validation.

src/ClaudeDo.Data/PromptFiles.cs

@@ -168,6 +168,12 @@ public static class PromptFiles
         - sonnet — normal coding work; the sensible default when unsure.
         - opus — only for genuinely complex, cross-cutting, or hard-to-debug work.
         Do not default everything to opus — most subtasks are haiku or sonnet.
+
+        Only for a subtask you can tell will need noticeably more turns than the
+        default budget (a large or sprawling piece of work), also pass CreateChildTask's
+        `maxTurns` argument with a generous turn count, so the run doesn't die mid-work
+        at the turn limit. Leave `maxTurns` null for everything else — it inherits the
+        list/global default.
         """;
 
     private const string PlanningInitialDefault = """

src/ClaudeDo.Data/Repositories/TaskRepository.cs

@@ -276,8 +276,12 @@ public sealed class TaskRepository
         string? commitType,
         string? createdBy = null,
         string? model = null,
+        int? maxTurns = null,
         CancellationToken ct = default)
     {
+        if (maxTurns.HasValue && maxTurns.Value <= 0)
+            throw new ArgumentException($"maxTurns must be positive, got {maxTurns.Value}.");
+
         // AsNoTracking: SetPlanningStartedAsync mutates via ExecuteUpdate which
         // bypasses the change tracker; a tracked Find would return stale data.
         var parent = await _context.Tasks.AsNoTracking()
@@ -303,6 +307,7 @@ public sealed class TaskRepository
             SortOrder = (maxSort ?? -1) + 1,
             CreatedBy = createdBy,
             Model = ModelRegistry.NormalizeAlias(model),
+            MaxTurns = maxTurns,
         };
         _context.Tasks.Add(child);
         await _context.SaveChangesAsync(ct);

src/ClaudeDo.Worker/CLAUDE.md

@@ -184,7 +184,7 @@ Loaded from `~/.todo-app/worker.config.json`:
   - The refresh token is NOT in this file — stored encrypted via DPAPI at `~/.todo-app/online-inbox.token`
 - `usage_poll_interval_seconds` (default 60, clamped to a minimum of 15 on load) — poll interval for `UsageMonitorService`
 
-Per-list config (`list_config` in DB) provides defaults for `model`, `system_prompt`, `agent_path`; tasks can override each individually. Task-generating MCP tools (`AddTask`, planning `CreateChildTask`, `SuggestImprovement`) accept an optional `model` (alias-validated via `ModelRegistry.NormalizeAlias` — `haiku`/`sonnet`/`opus`, blank = inherit) so Claude assigns the cheapest capable model at creation time; the planning/system/improvement prompts instruct it to do so (`ModelRegistry.ByCostAscending` = the cost order).
+Per-list config (`list_config` in DB) provides defaults for `model`, `system_prompt`, `agent_path`; tasks can override each individually. Task-generating MCP tools (`AddTask`, planning `CreateChildTask`, `SuggestImprovement`) accept an optional `model` (alias-validated via `ModelRegistry.NormalizeAlias` — `haiku`/`sonnet`/`opus`, blank = inherit) so Claude assigns the cheapest capable model at creation time; the planning/system/improvement prompts instruct it to do so (`ModelRegistry.ByCostAscending` = the cost order). Planning's `CreateChildTask` additionally accepts an optional `maxTurns` (positive int; `0`/negative rejected with `ArgumentException`, null = inherit list/global default) so the planner can raise the turn budget for a subtask it knows will run long; `SuggestImprovement`/`AddTask` do not expose it.
 
 ## Notes
 

src/ClaudeDo.Worker/Planning/PlanningMcpService.cs

@@ -41,16 +41,18 @@ public sealed class PlanningMcpService
         "Create a new draft child task under the current planning session's parent task. " +
         "Set model to the cheapest model that can do this subtask well — 'haiku' for trivial/mechanical " +
         "work, 'sonnet' for normal coding (the default), 'opus' only for complex or cross-cutting work. " +
-        "Leave model null to inherit the list/global default.")]
+        "Leave model null to inherit the list/global default. Set maxTurns only when this subtask is " +
+        "visibly larger than the default turn budget; leave it null to inherit the list/global default.")]
     public async Task<CreatedChildDto> CreateChildTask(
         string title,
         string? description,
         string? commitType,
         string? model,
-        CancellationToken cancellationToken)
+        int? maxTurns = null,
+        CancellationToken cancellationToken = default)
     {
         var ctx = _contextAccessor.Current;
-        var child = await _tasks.CreateChildAsync(ctx.ParentTaskId, title, description, commitType, createdBy: null, model: model, ct: cancellationToken);
+        var child = await _tasks.CreateChildAsync(ctx.ParentTaskId, title, description, commitType, createdBy: null, model: model, maxTurns: maxTurns, ct: cancellationToken);
         await BroadcastTaskUpdatedAsync(child.Id, cancellationToken);
         await BroadcastTaskUpdatedAsync(ctx.ParentTaskId, cancellationToken);
         return new CreatedChildDto(child.Id, child.Status.ToString());

tests/ClaudeDo.Worker.Tests/Planning/PlanningEndToEndTests.cs

@@ -111,8 +111,8 @@ public sealed class PlanningEndToEndTests : IDisposable
         // Wire the ambient context so _svc reads the correct parent
         _httpContext.Items["PlanningContext"] = new PlanningMcpContext { ParentTaskId = parent.Id };
 
-        await _svc.CreateChildTask("sub 1", null, null, null, CancellationToken.None);
+        await _svc.CreateChildTask("sub 1", null, null, null, cancellationToken: CancellationToken.None);
-        await _svc.CreateChildTask("sub 2", null, null, null, CancellationToken.None);
+        await _svc.CreateChildTask("sub 2", null, null, null, cancellationToken: CancellationToken.None);
 
         var count = await _svc.Finalize(true, CancellationToken.None);
         Assert.Equal(2, count);
@@ -155,9 +155,9 @@ public sealed class PlanningEndToEndTests : IDisposable
         await _manager.StartAsync(parent.Id, CancellationToken.None);
         _httpContext.Items["PlanningContext"] = new PlanningMcpContext { ParentTaskId = parent.Id };
 
-        await _svc.CreateChildTask("c1", null, null, null, CancellationToken.None);
+        await _svc.CreateChildTask("c1", null, null, null, cancellationToken: CancellationToken.None);
-        await _svc.CreateChildTask("c2", null, null, null, CancellationToken.None);
+        await _svc.CreateChildTask("c2", null, null, null, cancellationToken: CancellationToken.None);
-        await _svc.CreateChildTask("c3", null, null, null, CancellationToken.None);
+        await _svc.CreateChildTask("c3", null, null, null, cancellationToken: CancellationToken.None);
 
         var kidsBefore = await _tasks.GetChildrenAsync(parent.Id);
         var firstChildId = kidsBefore[0].Id;

tests/ClaudeDo.Worker.Tests/Planning/PlanningMcpServiceTests.cs

@@ -108,7 +108,7 @@ public sealed class PlanningMcpServiceTests : IDisposable
         var parent = await SeedPlanningParentAsync();
         var sut = BuildSut(parent.Id);
 
-        var result = await sut.CreateChildTask("My child", "desc", null, model: null, CancellationToken.None);
+        var result = await sut.CreateChildTask("My child", "desc", null, model: null, cancellationToken: CancellationToken.None);
 
         Assert.Equal("Idle", result.Status);
         var child = await _tasks.GetByIdAsync(result.TaskId);
@@ -123,7 +123,7 @@ public sealed class PlanningMcpServiceTests : IDisposable
         var parent = await SeedPlanningParentAsync();
         var sut = BuildSut(parent.Id);
 
-        var result = await sut.CreateChildTask("c", null, null, model: "Opus", CancellationToken.None);
+        var result = await sut.CreateChildTask("c", null, null, model: "Opus", cancellationToken: CancellationToken.None);
 
         var child = await _tasks.GetByIdAsync(result.TaskId);
         Assert.Equal("opus", child!.Model);
@@ -136,7 +136,43 @@ public sealed class PlanningMcpServiceTests : IDisposable
         var sut = BuildSut(parent.Id);
 
         await Assert.ThrowsAsync<ArgumentException>(
-            () => sut.CreateChildTask("c", null, null, model: "turbo", CancellationToken.None));
+            () => sut.CreateChildTask("c", null, null, model: "turbo", cancellationToken: CancellationToken.None));
+    }
+
+    [Fact]
+    public async Task CreateChildTask_NoMaxTurns_ChildInherits()
+    {
+        var parent = await SeedPlanningParentAsync();
+        var sut = BuildSut(parent.Id);
+
+        var result = await sut.CreateChildTask("c", null, null, model: null, cancellationToken: CancellationToken.None);
+
+        var child = await _tasks.GetByIdAsync(result.TaskId);
+        Assert.Null(child!.MaxTurns);
+    }
+
+    [Fact]
+    public async Task CreateChildTask_PersistsMaxTurns()
+    {
+        var parent = await SeedPlanningParentAsync();
+        var sut = BuildSut(parent.Id);
+
+        var result = await sut.CreateChildTask("c", null, null, model: null, maxTurns: 200, cancellationToken: CancellationToken.None);
+
+        var child = await _tasks.GetByIdAsync(result.TaskId);
+        Assert.Equal(200, child!.MaxTurns);
+    }
+
+    [Theory]
+    [InlineData(0)]
+    [InlineData(-1)]
+    public async Task CreateChildTask_RejectsInvalidMaxTurns(int maxTurns)
+    {
+        var parent = await SeedPlanningParentAsync();
+        var sut = BuildSut(parent.Id);
+
+        await Assert.ThrowsAsync<ArgumentException>(
+            () => sut.CreateChildTask("c", null, null, model: null, maxTurns: maxTurns, cancellationToken: CancellationToken.None));
     }
 
     [Fact]
@@ -267,7 +303,7 @@ public sealed class PlanningMcpServiceTests : IDisposable
         var parent = await SeedPlanningParentAsync();
         var sut = BuildSut(parent.Id);
 
-        var result = await sut.CreateChildTask("c", null, null, model: null, CancellationToken.None);
+        var result = await sut.CreateChildTask("c", null, null, model: null, cancellationToken: CancellationToken.None);
 
         var ids = TaskUpdatedIds();
         Assert.Contains(result.TaskId, ids);

tests/ClaudeDo.Worker.Tests/Repositories/TaskRepositoryPlanningTests.cs

@@ -119,6 +119,47 @@ public sealed class TaskRepositoryPlanningTests : IDisposable
             _tasks.CreateChildAsync("nonexistent-parent-id", "t", null, null));
     }
 
+    [Fact]
+    public async Task CreateChildAsync_NoMaxTurns_ChildInherits()
+    {
+        var listId = await CreateListAsync();
+        var parent = MakeTask(listId, phase: PlanningPhase.Active);
+        await _tasks.AddAsync(parent);
+
+        var child = await _tasks.CreateChildAsync(parent.Id, "child", null, null);
+
+        Assert.Null(child.MaxTurns);
+        var loaded = await _tasks.GetByIdAsync(child.Id);
+        Assert.Null(loaded!.MaxTurns);
+    }
+
+    [Fact]
+    public async Task CreateChildAsync_WithMaxTurns_Persists()
+    {
+        var listId = await CreateListAsync();
+        var parent = MakeTask(listId, phase: PlanningPhase.Active);
+        await _tasks.AddAsync(parent);
+
+        var child = await _tasks.CreateChildAsync(parent.Id, "child", null, null, maxTurns: 200);
+
+        Assert.Equal(200, child.MaxTurns);
+        var loaded = await _tasks.GetByIdAsync(child.Id);
+        Assert.Equal(200, loaded!.MaxTurns);
+    }
+
+    [Theory]
+    [InlineData(0)]
+    [InlineData(-5)]
+    public async Task CreateChildAsync_InvalidMaxTurns_Throws(int maxTurns)
+    {
+        var listId = await CreateListAsync();
+        var parent = MakeTask(listId, phase: PlanningPhase.Active);
+        await _tasks.AddAsync(parent);
+
+        await Assert.ThrowsAsync<ArgumentException>(() =>
+            _tasks.CreateChildAsync(parent.Id, "child", null, null, maxTurns: maxTurns));
+    }
+
     [Fact]
     public async Task SetPlanningStartedAsync_IdleTask_TransitionsToActivePhase()
     {