diff --git a/src/ClaudeDo.Worker/Runner/TaskRunner.cs b/src/ClaudeDo.Worker/Runner/TaskRunner.cs
index 0c05959..ce1246d 100644
--- a/src/ClaudeDo.Worker/Runner/TaskRunner.cs
+++ b/src/ClaudeDo.Worker/Runner/TaskRunner.cs
@@ -82,13 +82,7 @@ public sealed class TaskRunner
                 Directory.CreateDirectory(runDir);
             }
 
-            // Resolve config: task overrides > list config > null.
-            var resolvedConfig = new ClaudeRunConfig(
-                Model: task.Model ?? listConfig?.Model ?? "claude-sonnet-4-6",
-                SystemPrompt: task.SystemPrompt ?? listConfig?.SystemPrompt,
-                AgentPath: task.AgentPath ?? listConfig?.AgentPath,
-                ResumeSessionId: null
-            );
+            var resolvedConfig = await ResolveConfigAsync(task, listConfig, null, ct);
 
             var now = DateTime.UtcNow;
             using (var context = _dbFactory.CreateDbContext())
@@ -186,12 +180,7 @@ public sealed class TaskRunner
             worktree = await wtRepo.GetByTaskIdAsync(taskId, ct);
         }
 
-        var resolvedConfig = new ClaudeRunConfig(
-            Model: task.Model ?? listConfig?.Model,
-            SystemPrompt: task.SystemPrompt ?? listConfig?.SystemPrompt,
-            AgentPath: task.AgentPath ?? listConfig?.AgentPath,
-            ResumeSessionId: lastRun.SessionId
-        );
+        var resolvedConfig = await ResolveConfigAsync(task, listConfig, lastRun.SessionId, ct);
 
         // Determine run directory from existing worktree or sandbox.
         string runDir;
@@ -268,7 +257,7 @@ public sealed class TaskRunner
                 async line =>
                 {
                     await logWriter.WriteLineAsync(line, ct);
-                    await _broadcaster.TaskMessage(taskId, line);
+                    await _broadcaster.TaskMessage(taskId, "[stdout] " + line);
                 },
                 ct);
 
@@ -372,4 +361,35 @@ public sealed class TaskRunner
             _logger.LogError(ex, "Failed to mark task {TaskId} as failed", taskId);
         }
     }
+
+    private async Task<ClaudeRunConfig> ResolveConfigAsync(
+        TaskEntity task, ListConfigEntity? listConfig, string? resumeSessionId, CancellationToken ct)
+    {
+        AppSettingsEntity global;
+        using (var ctx = _dbFactory.CreateDbContext())
+        {
+            var settingsRepo = new AppSettingsRepository(ctx);
+            global = await settingsRepo.GetAsync(ct);
+        }
+
+        var instructions = MergeInstructions(
+            global.DefaultClaudeInstructions, listConfig?.SystemPrompt, task.SystemPrompt);
+
+        return new ClaudeRunConfig(
+            Model: task.Model ?? listConfig?.Model ?? global.DefaultModel,
+            SystemPrompt: string.IsNullOrWhiteSpace(instructions) ? null : instructions,
+            AgentPath: task.AgentPath ?? listConfig?.AgentPath,
+            ResumeSessionId: resumeSessionId,
+            MaxTurns: global.DefaultMaxTurns,
+            PermissionMode: global.DefaultPermissionMode);
+    }
+
+    public static string MergeInstructions(string? global, string? list, string? task)
+    {
+        var parts = new List<string>(3);
+        if (!string.IsNullOrWhiteSpace(global)) parts.Add(global.Trim());
+        if (!string.IsNullOrWhiteSpace(list)) parts.Add(list.Trim());
+        if (!string.IsNullOrWhiteSpace(task)) parts.Add(task.Trim());
+        return string.Join("\n\n", parts);
+    }
 }