Add usage limit feature to BaseTool class (#2904)

* Add usage limit feature to BaseTool class

- Add max_usage_count and current_usage_count attributes to BaseTool
- Implement usage limit checking in ToolUsage._use method
- Add comprehensive tests for usage limit functionality
- Maintain backward compatibility with None default for unlimited usage

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

* Fix CI failures and address code review feedback

- Add max_usage_count/current_usage_count to CrewStructuredTool
- Add input validation for positive max_usage_count
- Add reset_usage_count method to BaseTool
- Extract usage limit check into separate method
- Add comprehensive edge case tests
- Add proper type hints throughout
- Fix linting issues

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

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Joe Moura <joao@crewai.com>

src/crewai/tools/structured_tool.py

@@ -23,6 +23,8 @@ class CrewStructuredTool:
         args_schema: type[BaseModel],
         func: Callable[..., Any],
         result_as_answer: bool = False,
+        max_usage_count: int | None = None,
+        current_usage_count: int = 0,
     ) -> None:
         """Initialize the structured tool.
 
@@ -32,6 +34,8 @@ class CrewStructuredTool:
             args_schema: The pydantic model for the tool's arguments
             func: The function to run when the tool is called
             result_as_answer: Whether to return the output directly
+            max_usage_count: Maximum number of times this tool can be used. None means unlimited usage.
+            current_usage_count: Current number of times this tool has been used.
         """
         self.name = name
         self.description = description
@@ -39,6 +43,8 @@ class CrewStructuredTool:
         self.func = func
         self._logger = Logger()
         self.result_as_answer = result_as_answer
+        self.max_usage_count = max_usage_count
+        self.current_usage_count = current_usage_count
 
         # Validate the function signature matches the schema
         self._validate_function_signature()