refactor: default usage_limits to None

Author: tradeqvest

pydantic_ai_slim/pydantic_ai/_tool_manager.py

@@ -80,16 +80,13 @@ async def handle_call(
             allow_partial: Whether to allow partial validation of the tool arguments.
             wrap_validation_errors: Whether to wrap validation errors in a retry prompt part.
             usage_limits: Optional usage limits to check before executing tools.
-            count_tool_usage: Whether to count this tool call in usage metrics.
         """
         if self.tools is None or self.ctx is None:
             raise ValueError('ToolManager has not been prepared for a run step yet')  # pragma: no cover
 
         if (tool := self.tools.get(call.tool_name)) and tool.tool_def.kind == 'output':
             # Output tool calls are not traced and not counted
-            return await self._call_tool(
-                call, allow_partial, wrap_validation_errors, usage_limits, count_tool_usage=False
-            )
+            return await self._call_tool(call, allow_partial, wrap_validation_errors, count_tool_usage=False)
         else:
             return await self._call_tool_traced(
                 call,
@@ -105,7 +102,7 @@ async def _call_tool(
         call: ToolCallPart,
         allow_partial: bool,
         wrap_validation_errors: bool,
-        usage_limits: UsageLimits | None,
+        usage_limits: UsageLimits | None = None,
         count_tool_usage: bool = True,
     ) -> Any:
         if self.tools is None or self.ctx is None:
@@ -138,7 +135,7 @@ async def _call_tool(
             else:
                 args_dict = validator.validate_python(call.args or {}, allow_partial=pyd_allow_partial)
 
-            if usage_limits is not None:
+            if usage_limits is not None and count_tool_usage:
                 usage_limits.check_before_tool_call(self.ctx.usage)
 
             result = await self.toolset.call_tool(name, args_dict, ctx, tool)