fix: add idx for task ordering, tests

lib/crewai/src/crewai/crew.py

@@ -327,7 +327,7 @@ class Crew(FlowTrackable, BaseModel):
     def set_private_attrs(self) -> Crew:
         """set private attributes."""
         self._cache_handler = CacheHandler()
-        event_listener = EventListener()  # type: ignore[no-untyped-call]
+        event_listener = EventListener()
 
         # Determine and set tracing state once for this execution
         tracing_enabled = should_enable_tracing(override=self.tracing)
@@ -955,10 +955,20 @@ class Crew(FlowTrackable, BaseModel):
             tasks=self.tasks, planning_agent_llm=self.planning_llm
         )._handle_crew_planning()
 
-        for task, step_plan in zip(
-            self.tasks, result.list_of_plans_per_task, strict=False
-        ):
-            task.description += step_plan.plan
+        plan_map: dict[int, str] = {
+            step_plan.task_number: step_plan.plan
+            for step_plan in result.list_of_plans_per_task
+        }
+
+        for idx, task in enumerate(self.tasks):
+            task_number = idx + 1
+            if task_number in plan_map:
+                task.description += plan_map[task_number]
+            else:
+                self._logger.log(
+                    "warning",
+                    f"No plan found for Task Number {task_number}",
+                )
 
     def _store_execution_log(
         self,

lib/crewai/src/crewai/utilities/planning_handler.py

@@ -15,9 +15,12 @@ logger = logging.getLogger(__name__)
 class PlanPerTask(BaseModel):
     """Represents a plan for a specific task."""
 
-    task: str = Field(..., description="The task for which the plan is created")
+    task_number: int = Field(
+        description="The 1-indexed task number this plan corresponds to",
+        ge=1,
+    )
+    task: str = Field(description="The task for which the plan is created")
     plan: str = Field(
-        ...,
         description="The step by step plan on how the agents can execute their tasks using the available tools with mastery",
     )
 

lib/crewai/tests/utilities/test_planning_handler.py

@@ -1,7 +1,11 @@
-from unittest.mock import patch
+"""Tests for the planning handler module."""
+
+from unittest.mock import MagicMock, patch
 
 import pytest
+
 from crewai.agent import Agent
+from crewai.crew import Crew
 from crewai.knowledge.source.string_knowledge_source import StringKnowledgeSource
 from crewai.task import Task
 from crewai.tasks.task_output import TaskOutput
@@ -13,7 +17,7 @@ from crewai.utilities.planning_handler import (
 )
 
 
-class InternalCrewPlanner:
+class TestInternalCrewPlanner:
     @pytest.fixture
     def crew_planner(self):
         tasks = [
@@ -49,9 +53,9 @@ class InternalCrewPlanner:
 
     def test_handle_crew_planning(self, crew_planner):
         list_of_plans_per_task = [
-            PlanPerTask(task="Task1", plan="Plan 1"),
-            PlanPerTask(task="Task2", plan="Plan 2"),
-            PlanPerTask(task="Task3", plan="Plan 3"),
+            PlanPerTask(task_number=1, task="Task1", plan="Plan 1"),
+            PlanPerTask(task_number=2, task="Task2", plan="Plan 2"),
+            PlanPerTask(task_number=3, task="Task3", plan="Plan 3"),
         ]
         with patch.object(Task, "execute_sync") as execute:
             execute.return_value = TaskOutput(
@@ -166,7 +170,9 @@ class InternalCrewPlanner:
                 description="Description",
                 agent="agent",
                 pydantic=PlannerTaskPydanticOutput(
-                    list_of_plans_per_task=[PlanPerTask(task="Task1", plan="Plan 1")]
+                    list_of_plans_per_task=[
+                        PlanPerTask(task_number=1, task="Task1", plan="Plan 1")
+                    ]
                 ),
             )
             result = crew_planner_different_llm._handle_crew_planning()
@@ -177,3 +183,146 @@ class InternalCrewPlanner:
                 crew_planner_different_llm.tasks
             )
             execute.assert_called_once()
+
+    def test_plan_per_task_requires_task_number(self):
+        """Test that PlanPerTask model requires task_number field."""
+        with pytest.raises(ValueError):
+            PlanPerTask(task="Task1", plan="Plan 1")
+
+    def test_plan_per_task_with_task_number(self):
+        """Test PlanPerTask model with task_number field."""
+        plan = PlanPerTask(task_number=5, task="Task5", plan="Plan for task 5")
+        assert plan.task_number == 5
+        assert plan.task == "Task5"
+        assert plan.plan == "Plan for task 5"
+
+
+class TestCrewPlanningIntegration:
+    """Tests for Crew._handle_crew_planning integration with task_number matching."""
+
+    def test_crew_planning_with_out_of_order_plans(self):
+        """Test that plans are correctly matched to tasks even when returned out of order.
+
+        This test verifies the fix for issue #3953 where plans returned by the LLM
+        in a different order than the tasks would be incorrectly assigned.
+        """
+        agent1 = Agent(role="Agent 1", goal="Goal 1", backstory="Backstory 1")
+        agent2 = Agent(role="Agent 2", goal="Goal 2", backstory="Backstory 2")
+        agent3 = Agent(role="Agent 3", goal="Goal 3", backstory="Backstory 3")
+
+        task1 = Task(
+            description="First task description",
+            expected_output="Output 1",
+            agent=agent1,
+        )
+        task2 = Task(
+            description="Second task description",
+            expected_output="Output 2",
+            agent=agent2,
+        )
+        task3 = Task(
+            description="Third task description",
+            expected_output="Output 3",
+            agent=agent3,
+        )
+
+        crew = Crew(
+            agents=[agent1, agent2, agent3],
+            tasks=[task1, task2, task3],
+            planning=True,
+        )
+
+        out_of_order_plans = [
+            PlanPerTask(task_number=3, task="Task 3", plan=" [PLAN FOR TASK 3]"),
+            PlanPerTask(task_number=1, task="Task 1", plan=" [PLAN FOR TASK 1]"),
+            PlanPerTask(task_number=2, task="Task 2", plan=" [PLAN FOR TASK 2]"),
+        ]
+
+        mock_planner_result = PlannerTaskPydanticOutput(
+            list_of_plans_per_task=out_of_order_plans
+        )
+
+        with patch.object(
+            CrewPlanner, "_handle_crew_planning", return_value=mock_planner_result
+        ):
+            crew._handle_crew_planning()
+
+        assert "[PLAN FOR TASK 1]" in task1.description
+        assert "[PLAN FOR TASK 2]" in task2.description
+        assert "[PLAN FOR TASK 3]" in task3.description
+
+        assert "[PLAN FOR TASK 3]" not in task1.description
+        assert "[PLAN FOR TASK 1]" not in task2.description
+        assert "[PLAN FOR TASK 2]" not in task3.description
+
+    def test_crew_planning_with_missing_plan(self):
+        """Test that missing plans are handled gracefully with a warning."""
+        agent1 = Agent(role="Agent 1", goal="Goal 1", backstory="Backstory 1")
+        agent2 = Agent(role="Agent 2", goal="Goal 2", backstory="Backstory 2")
+
+        task1 = Task(
+            description="First task description",
+            expected_output="Output 1",
+            agent=agent1,
+        )
+        task2 = Task(
+            description="Second task description",
+            expected_output="Output 2",
+            agent=agent2,
+        )
+
+        crew = Crew(
+            agents=[agent1, agent2],
+            tasks=[task1, task2],
+            planning=True,
+        )
+
+        original_task1_desc = task1.description
+        original_task2_desc = task2.description
+
+        incomplete_plans = [
+            PlanPerTask(task_number=1, task="Task 1", plan=" [PLAN FOR TASK 1]"),
+        ]
+
+        mock_planner_result = PlannerTaskPydanticOutput(
+            list_of_plans_per_task=incomplete_plans
+        )
+
+        with patch.object(
+            CrewPlanner, "_handle_crew_planning", return_value=mock_planner_result
+        ):
+            crew._handle_crew_planning()
+
+        assert "[PLAN FOR TASK 1]" in task1.description
+
+        assert task2.description == original_task2_desc
+
+    def test_crew_planning_preserves_original_description(self):
+        """Test that planning appends to the original task description."""
+        agent = Agent(role="Agent 1", goal="Goal 1", backstory="Backstory 1")
+
+        task = Task(
+            description="Original task description",
+            expected_output="Output 1",
+            agent=agent,
+        )
+
+        crew = Crew(
+            agents=[agent],
+            tasks=[task],
+            planning=True,
+        )
+
+        plans = [
+            PlanPerTask(task_number=1, task="Task 1", plan=" - Additional plan steps"),
+        ]
+
+        mock_planner_result = PlannerTaskPydanticOutput(list_of_plans_per_task=plans)
+
+        with patch.object(
+            CrewPlanner, "_handle_crew_planning", return_value=mock_planner_result
+        ):
+            crew._handle_crew_planning()
+
+        assert "Original task description" in task.description
+        assert "Additional plan steps" in task.description