fix: correct CodeInterpreterSchema libraries_used field example

- Fix misleading Field description example that showed comma-separated string
- Change example from 'numpy,pandas,beautifulsoup4' to ['numpy', 'pandas', 'beautifulsoup4']
- Add comprehensive schema validation tests to prevent regression
- Resolves issue #3512 where LLM agents generated invalid input format

The libraries_used field expects List[str] but the example in the Field description
was showing a comma-separated string format, causing LLM agents to generate
input that failed Pydantic validation with 'Field required' errors.

Tests added:
- test_code_interpreter_schema_validation_valid_list: Verifies List[str] works
- test_code_interpreter_schema_validation_invalid_string: Verifies strings are rejected
- test_code_interpreter_schema_validation_empty_list: Verifies empty list works
- test_code_interpreter_schema_field_description: Verifies example format is correct

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

Author: devin-ai-integration[bot]

crewai_tools/tools/code_interpreter_tool/code_interpreter_tool.py

@@ -34,7 +34,7 @@ class CodeInterpreterSchema(BaseModel):
 
     libraries_used: List[str] = Field(
         ...,
-        description="List of libraries used in the code with proper installing names separated by commas. Example: numpy,pandas,beautifulsoup4",
+        description="List of libraries used in the code with proper installing names. Example: ['numpy', 'pandas', 'beautifulsoup4']",
     )
 
 

tests/tools/test_code_interpreter_tool.py

@@ -173,3 +173,51 @@ def test_unsafe_mode_running_unsafe_code(printer_mock, docker_unavailable_mock):
         "WARNING: Running code in unsafe mode", color="bold_magenta"
     )
     assert 5.0 == result
+
+
+def test_code_interpreter_schema_validation_valid_list():
+    """Test that CodeInterpreterSchema accepts valid List[str] for libraries_used."""
+    from crewai_tools.tools.code_interpreter_tool.code_interpreter_tool import CodeInterpreterSchema
+    
+    valid_input = CodeInterpreterSchema(
+        code="print('Hello, World!')",
+        libraries_used=["numpy", "pandas", "beautifulsoup4"]
+    )
+    assert valid_input.code == "print('Hello, World!')"
+    assert valid_input.libraries_used == ["numpy", "pandas", "beautifulsoup4"]
+
+
+def test_code_interpreter_schema_validation_invalid_string():
+    """Test that CodeInterpreterSchema rejects comma-separated string for libraries_used."""
+    from crewai_tools.tools.code_interpreter_tool.code_interpreter_tool import CodeInterpreterSchema
+    from pydantic import ValidationError
+    
+    with pytest.raises(ValidationError) as exc_info:
+        CodeInterpreterSchema(
+            code="print('Hello, World!')",
+            libraries_used="numpy,pandas,beautifulsoup4"
+        )
+    
+    assert "libraries_used" in str(exc_info.value)
+
+
+def test_code_interpreter_schema_validation_empty_list():
+    """Test that CodeInterpreterSchema accepts empty list for libraries_used."""
+    from crewai_tools.tools.code_interpreter_tool.code_interpreter_tool import CodeInterpreterSchema
+    
+    valid_input = CodeInterpreterSchema(
+        code="print('Hello, World!')",
+        libraries_used=[]
+    )
+    assert valid_input.libraries_used == []
+
+
+def test_code_interpreter_schema_field_description():
+    """Test that the Field description example shows proper List[str] format."""
+    from crewai_tools.tools.code_interpreter_tool.code_interpreter_tool import CodeInterpreterSchema
+    
+    schema_dict = CodeInterpreterSchema.model_json_schema()
+    libraries_used_description = schema_dict["properties"]["libraries_used"]["description"]
+    
+    assert "['numpy', 'pandas', 'beautifulsoup4']" in libraries_used_description
+    assert "numpy,pandas,beautifulsoup4" not in libraries_used_description