Fix: Replace SystemExit with LLMContextLengthExceededError in handle_context_length

- Changed handle_context_length to raise LLMContextLengthExceededError instead of SystemExit when respect_context_window=False
- This allows proper exception handling and prevents the entire application from terminating
- Added comprehensive unit tests to verify the fix
- Updated test imports to include LLMContextLengthExceededError

Fixes #3774

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

lib/crewai/src/crewai/utilities/agent_utils.py

@@ -419,7 +419,7 @@ def handle_context_length(
         i18n: I18N instance for messages
 
     Raises:
-        SystemExit: If context length is exceeded and user opts not to summarize
+        LLMContextLengthExceededError: If context length is exceeded and user opts not to summarize
     """
     if respect_context_window:
         printer.print(
@@ -432,7 +432,7 @@ def handle_context_length(
             content="Context length exceeded. Consider using smaller text or RAG tools from crewai_tools.",
             color="red",
         )
-        raise SystemExit(
+        raise LLMContextLengthExceededError(
             "Context length exceeded and user opted not to summarize. Consider using smaller text or RAG tools from crewai_tools."
         )
 

lib/crewai/tests/agents/test_agent.py

@@ -18,6 +18,9 @@ from crewai.process import Process
 from crewai.tools.tool_calling import InstructorToolCalling
 from crewai.tools.tool_usage import ToolUsage
 from crewai.utilities.errors import AgentRepositoryError
+from crewai.utilities.exceptions.context_window_exceeding_exception import (
+    LLMContextLengthExceededError,
+)
 import pytest
 
 from crewai import Agent, Crew, Task

lib/crewai/tests/utilities/test_agent_utils.py

@@ -0,0 +1,145 @@
+"""Test agent utility functions."""
+
+import pytest
+from unittest.mock import MagicMock, patch
+
+from crewai.agent import Agent
+from crewai.utilities.agent_utils import handle_context_length
+from crewai.utilities.exceptions.context_window_exceeding_exception import (
+    LLMContextLengthExceededError,
+)
+from crewai.utilities.i18n import I18N
+from crewai.utilities.printer import Printer
+
+
+def test_handle_context_length_raises_exception_when_respect_context_window_false():
+    """Test that handle_context_length raises LLMContextLengthExceededError when respect_context_window is False."""
+    # Create mocks for dependencies
+    printer = Printer()
+    i18n = I18N()
+
+    # Create an agent just for its LLM
+    agent = Agent(
+        role="test role",
+        goal="test goal",
+        backstory="test backstory",
+        respect_context_window=False,
+    )
+
+    llm = agent.llm
+
+    # Create test messages
+    messages = [
+        {
+            "role": "user",
+            "content": "This is a test message that would exceed context length",
+        }
+    ]
+
+    # Set up test parameters
+    respect_context_window = False
+    callbacks = []
+
+    with pytest.raises(LLMContextLengthExceededError) as excinfo:
+        handle_context_length(
+            respect_context_window=respect_context_window,
+            printer=printer,
+            messages=messages,
+            llm=llm,
+            callbacks=callbacks,
+            i18n=i18n,
+        )
+
+    assert "Context length exceeded" in str(excinfo.value)
+    assert "user opted not to summarize" in str(excinfo.value)
+
+
+def test_handle_context_length_summarizes_when_respect_context_window_true():
+    """Test that handle_context_length calls summarize_messages when respect_context_window is True."""
+    # Create mocks for dependencies
+    printer = Printer()
+    i18n = I18N()
+
+    # Create an agent just for its LLM
+    agent = Agent(
+        role="test role",
+        goal="test goal",
+        backstory="test backstory",
+        respect_context_window=True,
+    )
+
+    llm = agent.llm
+
+    # Create test messages
+    messages = [
+        {
+            "role": "user",
+            "content": "This is a test message that would exceed context length",
+        }
+    ]
+
+    # Set up test parameters
+    respect_context_window = True
+    callbacks = []
+
+    with patch("crewai.utilities.agent_utils.summarize_messages") as mock_summarize:
+        handle_context_length(
+            respect_context_window=respect_context_window,
+            printer=printer,
+            messages=messages,
+            llm=llm,
+            callbacks=callbacks,
+            i18n=i18n,
+        )
+
+        mock_summarize.assert_called_once_with(
+            messages=messages, llm=llm, callbacks=callbacks, i18n=i18n
+        )
+
+
+def test_handle_context_length_does_not_raise_system_exit():
+    """Test that handle_context_length does NOT raise SystemExit (regression test for issue #3774)."""
+    # Create mocks for dependencies
+    printer = Printer()
+    i18n = I18N()
+
+    # Create an agent just for its LLM
+    agent = Agent(
+        role="test role",
+        goal="test goal",
+        backstory="test backstory",
+        respect_context_window=False,
+    )
+
+    llm = agent.llm
+
+    # Create test messages
+    messages = [
+        {
+            "role": "user",
+            "content": "This is a test message that would exceed context length",
+        }
+    ]
+
+    # Set up test parameters
+    respect_context_window = False
+    callbacks = []
+
+    with pytest.raises(Exception) as excinfo:
+        handle_context_length(
+            respect_context_window=respect_context_window,
+            printer=printer,
+            messages=messages,
+            llm=llm,
+            callbacks=callbacks,
+            i18n=i18n,
+        )
+
+    assert not isinstance(excinfo.value, SystemExit), (
+        "handle_context_length should not raise SystemExit. "
+        "It should raise LLMContextLengthExceededError instead."
+    )
+
+    assert isinstance(excinfo.value, LLMContextLengthExceededError), (
+        f"Expected LLMContextLengthExceededError but got {type(excinfo.value).__name__}"
+    )