diff --git a/agent/nanobot/nanobot_test.go b/agent/nanobot/nanobot_test.go
index 9ffe03d..5507aa0 100644
--- a/agent/nanobot/nanobot_test.go
+++ b/agent/nanobot/nanobot_test.go
@@ -395,8 +395,8 @@ func TestArrWithTask(t *testing.T) {
 			it.True(errors.Is(err, errArr)),
 			it.Equal(len(chalk.tasks), 1),
 			it.Equal(chalk.tasks[0], "arr-step"),
-			it.Equal(chalk.dones, 1),
-			it.Equal(len(chalk.failed), 0),
+			it.Equal(chalk.dones, 0),
+			it.Equal(len(chalk.failed), 1),
 			it.Equal(chalk.subs, 1),
 		)
 	})
diff --git a/agent/nanobot/runtime.go b/agent/nanobot/runtime.go
index 160982a..0bb3f78 100644
--- a/agent/nanobot/runtime.go
+++ b/agent/nanobot/runtime.go
@@ -200,14 +200,19 @@ func (f Arr[S]) WithTaskf(taskf func(S) string, donef ...func(S) string) Arr[S]
 		}
 
 		c.Task(ctx, taskf(s))
-		defer func() {
-			if len(donef) > 0 && donef[0] != nil {
-				c.Done(donef[0](s))
-			} else {
-				c.Done()
-			}
-		}()
-		return f(c.Sub(ctx), s, opt...)
+		val, err := f(c.Sub(ctx), s, opt...)
+		if err != nil {
+			c.Fail(err)
+			return val, err
+		}
+
+		if len(donef) > 0 && donef[0] != nil {
+			c.Done(donef[0](s))
+		} else {
+			c.Done()
+		}
+
+		return val, err
 	}
 }