Harden MCP article and weight workflows

README.md

@@ -118,8 +118,10 @@ Authentication is implemented with `Flask-HTTPAuth`. The current code checks `BE
 
 `mcp_server.py` provides a local stdio-only Model Context Protocol server. It is
 a thin adapter over the same domain services used by Flask: article lookup,
-direct roll calculation, and transport analysis. The available PoC tools are
-`get_article`, `calculate_roll_diameter`, and `analyze_transport_capacity`.
+direct roll calculation, material-weight calculation, and transport analysis.
+The available PoC tools are `get_article`, `search_articles`,
+`calculate_material_weight`, `calculate_roll_diameter`, and
+`analyze_transport_capacity`.
 
 Install the pinned dependencies, including `mcp==1.26.0`, in the existing
 environment, then start it with:
@@ -136,11 +138,19 @@ Tool calling semantics:
 
 - `get_article` accepts textual `article_number` values (including leading
   zeroes) and an optional `article_name_hint`.
+- `search_articles` deterministically returns master-data candidates for a
+  product name or designation. Its ordering is retrieval relevance, not a
+  product recommendation: when multiple candidates remain, callers must ask
+  the user to select an article number rather than choosing one.
+- `calculate_material_weight` calculates material-only weight from roll length,
+  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_roll_diameter` uses `roll_length_m` for the material length on one
   roll. Diameter and thickness inputs are in mm; `width_m` is in m;
-  `area_weight_g_m2` is in g/m². It always requests the available kilogram
-  result and, on success, returns `transport_roll_inputs`, the browser-equivalent
-  transport bundle.
+  `area_weight_g_m2` is in g/m². It requires a known positive core diameter;
+  use `calculate_material_weight` when the core is unknown and only material
+  weight is needed. On success, it returns `transport_roll_inputs`, the
+  browser-equivalent transport bundle.
 - `analyze_transport_capacity` uses roll/core diameters in mm; roll width and
   transport dimensions in m; and roll/payload weights in kg.
   `product_length_m` is the material length represented by one roll, used only