Allow direct article resolution in machine max MCP

README.md

@@ -150,8 +150,9 @@ Tool calling semantics:
   width, and area weight. It requires no core diameter, does not infer one, and
   cannot return a roll diameter or a core-inclusive total weight.
 - `calculate_machine_max_product_length` composes configured machine limits
-  with the shared calculation domain. Resolve an article first, then pass its
+  with the shared calculation domain. With an exact article number, MCP resolves
-  properties unchanged. Its nominal maximum uses the nominal diameter limit;
+  its properties internally; otherwise callers pass explicit properties. Its
+  nominal maximum uses the nominal diameter limit;
   its conservative/no-warning maximum uses RollCalc's existing maximum-diameter
   thickness variation. Both also respect configured material-only maximum roll
   weight, and the domain returns the governing constraint(s), unrounded.

mcp_server.py

@@ -67,15 +67,17 @@ def create_server() -> Any:
     def calculate_machine_max_product_length(
         machine: str,
         core_diameter_mm: float,
-        thickness_mm: float,
+        article_number: str | None = None,
+        thickness_mm: float | None = None,
         thickness_stddev_mm: float | None = None,
         product_width_m: float | None = None,
         area_weight_g_m2: float | None = None,
     ) -> dict[str, Any]:
-        """Calculate deterministic maximum product length for a configured production machine. Use this for maximum roll/product length, how much product fits on a machine roll, or maximum length without a diameter warning. Resolve the article first with search_articles/get_article when needed, then pass its thickness, thickness standard deviation, width, and area weight exactly. Do not supply or invent machine limits, rearrange roll or weight formulas, calculate a weight-limited length, or compare candidate limits yourself: this tool returns nominal and conservative/no-warning production maxima and their governing constraints. Report incompatibility rather than substituting another core or width, and ask for returned missing inputs rather than inventing them."""
+        """Calculate deterministic maximum product length for a configured production machine. With an exact article_number, call this directly with machine and caller-supplied core_diameter_mm; do not call get_article merely to copy properties. Otherwise supply explicit material properties. Never mix article_number with material properties. For a product name, use search_articles; if candidates are multiple, ask the user to select an article number. Do not supply or invent machine limits or substitute a core or width; this returns nominal and conservative/no-warning production maxima and governing constraints."""
         return calculate_machine_max_product_length_result(
             machine=machine,
             core_diameter_mm=core_diameter_mm,
+            article_number=article_number,
             thickness_mm=thickness_mm,
             thickness_stddev_mm=thickness_stddev_mm,
             product_width_m=product_width_m,

rollcalc_mcp_tools.py

@@ -64,12 +64,48 @@ def calculate_machine_max_product_length_result(
     *,
     machine: str,
     core_diameter_mm: float,
-    thickness_mm: float,
+    article_number: str | None = None,
+    thickness_mm: float | None = None,
     thickness_stddev_mm: float | None = None,
     product_width_m: float | None = None,
     area_weight_g_m2: float | None = None,
 ) -> dict[str, Any]:
-    """Return the compact MCP view of the machine-aware domain calculation."""
+    """Return the compact MCP view, resolving one exact article when supplied."""
+    explicit_material = {
+        "thickness_mm": thickness_mm,
+        "thickness_stddev_mm": thickness_stddev_mm,
+        "product_width_m": product_width_m,
+        "area_weight_g_m2": area_weight_g_m2,
+    }
+    if article_number is not None:
+        mixed_fields = [
+            field for field, value in explicit_material.items() if value is not None
+        ]
+        if mixed_fields:
+            return {
+                "status": "invalid_parameter",
+                "invalid": [{
+                    "field": "article_number",
+                    "message": (
+                        "cannot be combined with explicit material properties: "
+                        + ", ".join(mixed_fields)
+                    ),
+                }],
+            }
+        article_result = get_article(article_number)
+        if article_result["status"] != "resolved":
+            return article_result
+        article = article_result["article"]
+        result = calculate_machine_max_product_length(
+            machine=machine,
+            core_diameter_mm=core_diameter_mm,
+            thickness_mm=article["thickness_mm"],
+            thickness_stddev_mm=article["thickness_stddev_mm"],
+            product_width_m=article["width_m"],
+            area_weight_g_m2=article["area_weight_g_m2"],
+        )
+        return project_machine_max_product_length_result(result, article=article)
+
     result = calculate_machine_max_product_length(
         machine=machine,
         core_diameter_mm=core_diameter_mm,
@@ -81,7 +117,11 @@ def calculate_machine_max_product_length_result(
     return project_machine_max_product_length_result(result)
 
 
-def project_machine_max_product_length_result(result: dict[str, Any]) -> dict[str, Any]:
+def project_machine_max_product_length_result(
+    result: dict[str, Any],
+    *,
+    article: dict[str, Any] | None = None,
+) -> dict[str, Any]:
     """Project successful maximum-length results for MCP without diagnostics.
 
     The shared domain result deliberately contains detailed verification reports.
@@ -93,7 +133,7 @@ def project_machine_max_product_length_result(result: dict[str, Any]) -> dict[st
 
     machine = result["machine"]
     constraints = machine["constraints"]
-    return {
+    projection = {
         "status": result["status"],
         "machine": {"id": machine["id"], "name": machine["name"]},
         "weight_scope": result["weight_scope"],
@@ -107,6 +147,12 @@ def project_machine_max_product_length_result(result: dict[str, Any]) -> dict[st
         "material_weights_kg": result["material_weights_kg"],
         "warnings": result["warnings"],
     }
+    if article is not None:
+        projection["article"] = {
+            "number": article["number"],
+            "name": article["name"],
+        }
+    return projection
 
 
 def calculate_material_weight_result(

tests/test_calculation_api.py

@@ -164,6 +164,26 @@ class CalculationApiTests(unittest.TestCase):
             ["roll_diameter_nominal"],
         )
 
+    def test_machine_maximum_length_endpoint_does_not_accept_mcp_article_convenience(self):
+        response = self.client.post(
+            "/api/calculations/machine-max-product-length",
+            json={
+                "article_number": "218500",
+                "machine": "K7",
+                "core_diameter_mm": 133,
+            },
+            headers=self.headers,
+        )
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.get_json(), {
+            "status": "invalid_parameter",
+            "invalid": [{
+                "field": "request",
+                "message": "unknown request fields: article_number",
+            }],
+        })
+
     def test_machine_maximum_length_endpoint_preserves_domain_outcomes(self):
         incompatible = self.client.post(
             "/api/calculations/machine-max-product-length",

tests/test_mcp_adapter.py

@@ -117,6 +117,10 @@ class McpAdapterTests(unittest.TestCase):
         domain_result = calculate_machine_max_product_length(**arguments)
         domain_before_projection = copy.deepcopy(domain_result)
 
+        self.assertNotIn(
+            "article_number",
+            inspect.signature(calculate_machine_max_product_length).parameters,
+        )
         result = project_machine_max_product_length_result(domain_result)
 
         self.assertEqual(domain_result, domain_before_projection)
@@ -143,6 +147,72 @@ class McpAdapterTests(unittest.TestCase):
         })
         self.assertEqual(result["warnings"], {"nominal": ["roll_diameter_mm"]})
 
+    def test_machine_maximum_length_adapter_resolves_exact_article_compactly(self):
+        result = calculate_machine_max_product_length_result(
+            article_number="218500",
+            machine="K7",
+            core_diameter_mm=133.0,
+        )
+
+        self.assertEqual(result["status"], "success")
+        self.assertEqual(result["article"], {
+            "number": "218500",
+            "name": "Stex AS 501,      6,00 x 75 m",
+        })
+        self.assertNotIn("thickness_mm", result)
+        self.assertNotIn("final_feasibility", result)
+        self.assertEqual(result["production_maximums"], {
+            "nominal_length_m": 217.1900177447768,
+            "nominal_governing_constraints": ["roll_diameter_nominal"],
+            "conservative_length_m": 194.62073281485985,
+            "conservative_governing_constraints": ["roll_diameter_conservative"],
+        })
+        self.assertEqual(result["material_weights_kg"], {
+            "at_nominal_production_maximum": 645.570178559751,
+            "at_conservative_production_maximum": 578.4858003113276,
+        })
+
+    def test_machine_maximum_length_adapter_article_lookup_is_exact_and_core_is_caller_supplied(self):
+        missing = calculate_machine_max_product_length_result(
+            article_number="does-not-exist",
+            machine="K7",
+            core_diameter_mm=133.0,
+        )
+        incompatible_core = calculate_machine_max_product_length_result(
+            article_number="218500",
+            machine="K7",
+            core_diameter_mm=194.0,
+        )
+
+        self.assertEqual(missing, {
+            "status": "article_not_found",
+            "article_number": "does-not-exist",
+        })
+        self.assertEqual(incompatible_core["status"], "incompatible")
+        self.assertEqual(
+            incompatible_core["failed_compatibility_constraints"],
+            ["allowed_core_diameters_mm"],
+        )
+
+    def test_machine_maximum_length_adapter_rejects_mixed_article_and_material_inputs(self):
+        result = calculate_machine_max_product_length_result(
+            article_number="218500",
+            machine="K7",
+            core_diameter_mm=133.0,
+            thickness_mm=4.311611,
+        )
+
+        self.assertEqual(result, {
+            "status": "invalid_parameter",
+            "invalid": [{
+                "field": "article_number",
+                "message": (
+                    "cannot be combined with explicit material properties: "
+                    "thickness_mm"
+                ),
+            }],
+        })
+
     def test_machine_maximum_length_adapter_preserves_non_success_diagnostics(self):
         base = {
             "machine": "K7",
@@ -344,17 +414,19 @@ class McpAdapterTests(unittest.TestCase):
         self.assertIn("Missing configured V1 roll inputs", feasibility_tool.description)
         self.assertEqual(
             maximum_tool.parameters["required"],
-            ["machine", "core_diameter_mm", "thickness_mm"],
+            ["machine", "core_diameter_mm"],
         )
+        self.assertIn("article_number", maximum_tool.parameters["properties"])
         self.assertIn("product_width_m", maximum_tool.parameters["properties"])
         self.assertIn("area_weight_g_m2", maximum_tool.parameters["properties"])
         for text in (
-            "Resolve the article first with search_articles/get_article",
+            "exact article_number",
+            "do not call get_article merely to copy properties",
+            "Never mix article_number with material properties",
+            "For a product name, use search_articles",
+            "if candidates are multiple, ask the user to select an article number",
             "Do not supply or invent machine limits",
-            "rearrange roll or weight formulas",
-            "compare candidate limits yourself",
             "nominal and conservative/no-warning production maxima",
-            "incompatibility rather than substituting another core or width",
         ):
             self.assertIn(text, maximum_tool.description)
         self.assertEqual(