Update tools/calculator.py

tools/calculator.py

@@ -1,12 +1,45 @@
-from smolagents.tools import Tools
-from typing import Any, Optional
-import duckduckgo_search
+from smolagents.tools import Tool
+
 
 class Calculator(Tool):
     name = "calculator"
-    description = "takes numbers and performs some arithmetic eg addition, subtraction"
+
+    description = (
+        "Performs deterministic arithmetic calculations. "
+        "Use this when a research task requires numerical computation."
+    )
+
     inputs = {
-        numbers: {float}
+        "expression": {
+            "type": "string",
+            "description": (
+                "A mathematical expression to evaluate, "
+                "for example '125 * 0.18' or '(450 - 300) / 300 * 100'."
+            ),
+        }
     }
-    output_type = float
+
+    output_type = "number"
+
+    def forward(self, expression: str) -> float:
+        try:
+            # Restrict evaluation to arithmetic only.
+            allowed = set("0123456789+-*/().% ")
+
+            if not expression or any(char not in allowed for char in expression):
+                raise ValueError("Expression contains unsupported characters.")
+
+            expression = expression.replace("%", "/100")
+
+            result = eval(expression, {"__builtins__": {}}, {})
+
+            if not isinstance(result, (int, float)):
+                raise ValueError("Expression did not produce a number.")
+
+            return float(result)
+
+        except Exception as e:
+            raise ValueError(
+                f"Could not evaluate expression '{expression}': {e}"
+            ) from e