fix: remove duplicate constraint injection in context, fix unused import

- Remove constraint text injection into context string (constraints are
  already rendered by Task.prompt() via the constraints field)
- Remove unused MagicMock import from test file
- Update tests to verify context is passed through unchanged

Addresses review feedback from Cursor Bugbot and github-code-quality bot.

Co-Authored-By: João <joao@crewai.com>

lib/crewai/src/crewai/tools/agent_tools/base_agent_tools.py

@@ -56,8 +56,8 @@ class BaseAgentTool(BaseTool):
         Execute delegation to an agent with case-insensitive and whitespace-tolerant matching.
 
         When the original_task has constraints defined, they are automatically
-        propagated to the delegated task and appended to the context so that
-        the worker agent is aware of all original requirements.
+        propagated to the delegated Task object. The constraints are then
+        rendered by Task.prompt() so the worker agent sees them.
 
         Args:
             agent_name: Name/role of the agent to delegate to (case-insensitive)
@@ -122,7 +122,10 @@ class BaseAgentTool(BaseTool):
 
         selected_agent = agent[0]
         try:
-            # Propagate constraints from the original task to the delegated task
+            # Propagate constraints from the original task to the delegated task.
+            # Constraints are set on the Task object so that Task.prompt() renders
+            # them for the worker agent — no need to also inject them into `context`,
+            # which would cause duplication.
             constraints: list[str] = []
             if self.original_task and self.original_task.constraints:
                 constraints = list(self.original_task.constraints)
@@ -132,15 +135,6 @@ class BaseAgentTool(BaseTool):
                     self.sanitize_agent_name(selected_agent.role),
                     constraints,
                 )
-                # Append constraints to context so the worker agent sees them
-                constraints_text = (
-                    "\n\nTask Constraints (MUST be respected):\n"
-                    + "\n".join(f"- {c}" for c in constraints)
-                )
-                if context:
-                    context = context + constraints_text
-                else:
-                    context = constraints_text
 
             task_with_assigned_agent = Task(
                 description=task,

lib/crewai/tests/tools/agent_tools/test_constraint_propagation.py

@@ -8,7 +8,7 @@ See: https://github.com/crewAIInc/crewAI/issues/5476
 """
 
 import logging
-from unittest.mock import MagicMock, patch
+from unittest.mock import patch
 
 import pytest
 
@@ -156,17 +156,14 @@ class TestConstraintPropagationInDelegation:
             "Only frameworks available in Europe",
         ]
 
-        # The context should include the constraints
-        assert "Task Constraints (MUST be respected):" in delegated_context
-        assert "- Only open-source frameworks" in delegated_context
-        assert "- Must be from 2024" in delegated_context
-        assert "- Only frameworks available in Europe" in delegated_context
+        # Context should NOT be modified — constraints are rendered via Task.prompt()
+        assert delegated_context == "Need a comprehensive list"
 
     @patch.object(Agent, "execute_task")
-    def test_constraints_appended_to_existing_context(
+    def test_context_not_modified_by_constraints(
         self, mock_execute, researcher, writer, task_with_constraints
     ):
-        """When context already exists, constraints are appended to it."""
+        """Context is passed through unchanged; constraints live on the Task object."""
         mock_execute.return_value = "result"
 
         tools = AgentTools(agents=[researcher], task=task_with_constraints).tools()
@@ -179,12 +176,13 @@ class TestConstraintPropagationInDelegation:
         )
 
         mock_execute.assert_called_once()
+        delegated_task = mock_execute.call_args[0][0]
         delegated_context = mock_execute.call_args[0][1]
 
-        # Original context should still be there
-        assert delegated_context.startswith("Previous context here")
-        # Constraints should be appended
-        assert "Task Constraints (MUST be respected):" in delegated_context
+        # Context should be unchanged
+        assert delegated_context == "Previous context here"
+        # Constraints should be on the task object
+        assert len(delegated_task.constraints) == 3
 
     @patch.object(Agent, "execute_task")
     def test_no_constraints_no_modification(
@@ -230,13 +228,14 @@ class TestConstraintPropagationInDelegation:
         delegated_context = mock_execute.call_args[0][1]
 
         assert delegated_task.constraints == task_with_constraints.constraints
-        assert "Task Constraints (MUST be respected):" in delegated_context
+        # Context should be unchanged — constraints live on the task
+        assert delegated_context == "Need details"
 
     @patch.object(Agent, "execute_task")
     def test_constraints_propagated_when_no_original_context(
         self, mock_execute, researcher, writer, task_with_constraints
     ):
-        """When delegation has no context, constraints become the context."""
+        """Even with empty context, constraints are on the task, not injected into context."""
         mock_execute.return_value = "result"
 
         tools = AgentTools(agents=[researcher], task=task_with_constraints).tools()
@@ -249,10 +248,13 @@ class TestConstraintPropagationInDelegation:
         )
 
         mock_execute.assert_called_once()
+        delegated_task = mock_execute.call_args[0][0]
         delegated_context = mock_execute.call_args[0][1]
 
-        # Empty string context means constraints text is appended to empty string
-        assert "Task Constraints (MUST be respected):" in delegated_context
+        # Context should remain empty
+        assert delegated_context == ""
+        # Constraints are on the task object
+        assert delegated_task.constraints == task_with_constraints.constraints
 
     @patch.object(Agent, "execute_task")
     def test_delegation_without_original_task_works(