Expose product length calculation through MCP

mcp_server.py

@@ -7,6 +7,7 @@ from typing import Any
 from rollcalc_mcp_tools import (
     analyze_transport_capacity_result,
     calculate_material_weight_result,
+    calculate_product_length_result,
     calculate_roll_diameter_result,
     get_article_result,
     search_articles_result,
@@ -46,6 +47,25 @@ def create_server() -> Any:
             area_weight_g_m2=area_weight_g_m2,
         )
 
+    @server.tool()
+    def calculate_product_length(
+        target_roll_diameter_mm: float,
+        core_diameter_mm: float,
+        thickness_mm: float,
+        thickness_stddev_mm: float | None = None,
+        width_m: float | None = None,
+        area_weight_g_m2: float | None = None,
+    ) -> dict[str, Any]:
+        """Calculate required product/roll length for a target outer roll diameter. target_roll_diameter_mm, core_diameter_mm, and thickness_mm are required and expressed in mm. Use exact article master-data values obtained through get_article when available; do not infer a missing core diameter, thickness, width, area weight, or article. thickness_stddev_mm returns deterministic minimum, average, and maximum length ranges. When both width_m (m) and area_weight_g_m2 (g/m²) are supplied, the result also includes corresponding material-weight ranges. This tool calculates length from target diameter; use calculate_roll_diameter for the reverse direction."""
+        return calculate_product_length_result(
+            target_roll_diameter_mm=target_roll_diameter_mm,
+            core_diameter_mm=core_diameter_mm,
+            thickness_mm=thickness_mm,
+            thickness_stddev_mm=thickness_stddev_mm,
+            width_m=width_m,
+            area_weight_g_m2=area_weight_g_m2,
+        )
+
     @server.tool()
     def calculate_roll_diameter(
         roll_length_m: float | None = None,