Fix prompt formatting biases affecting JSON output

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

tests/tools/test_json_formatting.py

@@ -0,0 +1,78 @@
+import json
+from unittest.mock import MagicMock
+
+import pytest
+from pydantic import BaseModel, Field
+
+from crewai.tools import BaseTool
+from crewai.tools.tool_usage import ToolUsage
+
+
+class TestJsonInput(BaseModel):
+    test_param: str = Field(
+        ..., description="A test parameter"
+    )
+    another_param: int = Field(
+        ..., description="Another test parameter"
+    )
+
+
+class TestJsonTool(BaseTool):
+    name: str = "Test JSON Tool"
+    description: str = "A tool for testing JSON formatting"
+    args_schema: type[BaseModel] = TestJsonInput
+
+    def _run(self, test_param: str, another_param: int) -> str:
+        return f"Received {test_param} and {another_param}"
+
+
+def test_tool_description_json_formatting():
+    """Test that the tool description uses proper JSON formatting with double quotes."""
+    tool = TestJsonTool()
+    
+    assert "Tool Arguments:" in tool.description
+    
+    description_parts = tool.description.split("Tool Arguments: ")
+    json_str = description_parts[1].split("\nTool Description:")[0]
+    
+    parsed_json = json.loads(json_str)
+    
+    assert "test_param" in parsed_json
+    assert "another_param" in parsed_json
+    
+    assert '"test_param"' in json_str
+    assert '"another_param"' in json_str
+    assert "'" not in json_str  # No single quotes should be present
+
+
+def test_tool_usage_json_formatting():
+    """Test that the tool usage renders with proper JSON formatting."""
+    tool = TestJsonTool()
+
+    tool_usage = ToolUsage(
+        tools_handler=MagicMock(),
+        tools=[tool],
+        original_tools=[tool],
+        tools_description="Tool for testing JSON formatting",
+        tools_names="test_json_tool",
+        task=MagicMock(),
+        function_calling_llm=MagicMock(),
+        agent=MagicMock(),
+        action=MagicMock(),
+    )
+
+    rendered = tool_usage._render()
+    
+    rendered_parts = rendered.split("Tool Arguments: ")
+    if len(rendered_parts) > 1:
+        json_str = rendered_parts[1].split("\nTool Description:")[0]
+        
+        try:
+            parsed_json = json.loads(json_str)
+            assert True  # If we get here, JSON parsing succeeded
+        except json.JSONDecodeError:
+            assert False, "The rendered tool arguments are not valid JSON"
+        
+        assert '"test_param"' in json_str
+        assert '"another_param"' in json_str
+        assert "'" not in json_str  # No single quotes should be present