diff --git a/SKILL.md b/SKILL.md
index 1be48d5..b710270 100644
--- a/SKILL.md
+++ b/SKILL.md
@@ -82,8 +82,13 @@ Schema:
   — these overlap heavily with the above, so a few smart picks (oily fish, eggs with
   yolk, greens, nuts/seeds) cover all three goals at once. Don't overcomplicate; note
   them as gentle "health boost" lines, not medical advice.
-- If the inventory is too sparse for a real meal, say so and list the top 2–3
-  things to buy.
+- **STRICT inventory rule:** both daily meals MUST be built ONLY from items the user
+  ACTUALLY HAS in `inventory.json` at the time. Never invent, assume, or add an
+  ingredient that isn't listed there. Recipe/web inspiration is fine, but only use
+  in-stock items — substitute with an in-stock item or drop the idea. Before sending,
+  cross-check every ingredient against inventory.json and remove anything not present.
+  If stock is too sparse for a real high-protein meal, say so and list the top 2–3
+  things to buy — do NOT fabricate meals from items you don't have.
 
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