diff --git a/pi/core/skills/bengali-nlp/SKILL.md b/pi/core/skills/bengali-nlp/SKILL.md
index e5dabca16..5e077565c 100644
--- a/pi/core/skills/bengali-nlp/SKILL.md
+++ b/pi/core/skills/bengali-nlp/SKILL.md
@@ -186,13 +186,17 @@ BANGLA_STOP_WORDS = {
     "এবং", "ও", "এ", "এই", "সেই", "তার", "যে", "একটি",
     "করে", "হয়", "আর", "কিন্তু", "তবে", "যদি", "তাহলে",
     "আমি", "তুমি", "সে", "আমরা", "তোমরা", "তারা",
-    "হবে", "ছিল", "আছে", "নেই", "থেকে", "জন্য", "সাথে",
+    "হবে", "ছিল", "আছে", "থেকে", "জন্য", "সাথে",
     "পর", "আগে", "উপর", "নিচে", "মধ্যে", "দিয়ে",
     "কি", "কে", "কোন", "কোথায়", "কেন", "কিভাবে",
-    "না", "নয়", "হ্যাঁ", "অনেক", "কিছু", "সব", "প্রতি",
+    "হ্যাঁ", "অনেক", "কিছু", "সব", "প্রতি",
 }
 ```
 
+Keep negators such as `না`, `নয়`, and `নেই` out of a generic stop-word list.
+They change intent and sentiment, so remove them only for a task that explicitly
+models negation elsewhere.
+
 ### Sorting and Collation
 
 Bengali has a defined sort order (স্বরবর্ণ before ব্যঞ্জনবর্ণ). Use locale-aware sorting:
diff --git a/pi/core/skills/mybatis-patterns/SKILL.md b/pi/core/skills/mybatis-patterns/SKILL.md
index c34922dba..582d05f71 100644
--- a/pi/core/skills/mybatis-patterns/SKILL.md
+++ b/pi/core/skills/mybatis-patterns/SKILL.md
@@ -200,15 +200,17 @@ public List<UserSummary> search(UserSearchRequest request) {
 }
 ```
 
-The mapper retains the `ids.size() > 0` guard as defense in depth, but callers
-must not rely on an empty `<foreach>` to define query semantics. The service
-boundary must ensure this query is reached only with a non-empty list or a
-deliberate `null` meaning "no ID filter".
+The mapper retains the `ids.size() > 0` guard as defense in depth. That guard
+omits the entire ID predicate for an empty list, which broadens the query. The
+service must short-circuit empty lists before calling the mapper, and any caller
+that bypasses the service must reject empty IDs before query execution. Reserve
+`null` for the deliberate "no ID filter" case.
 
 - Prefer `<where>`, `<set>`, `<trim>`, `<choose>`, and `<foreach>` to manual
   string concatenation.
-- Define the empty-list behavior in the service. Return no rows, skip the
-  query, or apply an explicit false predicate; never rely on `IN ()` behavior.
+- Define the empty-list behavior in the service. Return no rows, skip the query,
+  or apply an explicit false predicate; never let an empty list silently remove
+  the ID predicate or rely on `IN ()` behavior.
 - Keep the allowed shape of dynamic SQL small. If a query has many branches,
   split it into named statements or move carefully selected alternatives into
   separate mapper methods.
diff --git a/skills/bengali-nlp/SKILL.md b/skills/bengali-nlp/SKILL.md
index e5dabca16..5e077565c 100644
--- a/skills/bengali-nlp/SKILL.md
+++ b/skills/bengali-nlp/SKILL.md
@@ -186,13 +186,17 @@ BANGLA_STOP_WORDS = {
     "এবং", "ও", "এ", "এই", "সেই", "তার", "যে", "একটি",
     "করে", "হয়", "আর", "কিন্তু", "তবে", "যদি", "তাহলে",
     "আমি", "তুমি", "সে", "আমরা", "তোমরা", "তারা",
-    "হবে", "ছিল", "আছে", "নেই", "থেকে", "জন্য", "সাথে",
+    "হবে", "ছিল", "আছে", "থেকে", "জন্য", "সাথে",
     "পর", "আগে", "উপর", "নিচে", "মধ্যে", "দিয়ে",
     "কি", "কে", "কোন", "কোথায়", "কেন", "কিভাবে",
-    "না", "নয়", "হ্যাঁ", "অনেক", "কিছু", "সব", "প্রতি",
+    "হ্যাঁ", "অনেক", "কিছু", "সব", "প্রতি",
 }
 ```
 
+Keep negators such as `না`, `নয়`, and `নেই` out of a generic stop-word list.
+They change intent and sentiment, so remove them only for a task that explicitly
+models negation elsewhere.
+
 ### Sorting and Collation
 
 Bengali has a defined sort order (স্বরবর্ণ before ব্যঞ্জনবর্ণ). Use locale-aware sorting:
diff --git a/skills/mybatis-patterns/SKILL.md b/skills/mybatis-patterns/SKILL.md
index c34922dba..582d05f71 100644
--- a/skills/mybatis-patterns/SKILL.md
+++ b/skills/mybatis-patterns/SKILL.md
@@ -200,15 +200,17 @@ public List<UserSummary> search(UserSearchRequest request) {
 }
 ```
 
-The mapper retains the `ids.size() > 0` guard as defense in depth, but callers
-must not rely on an empty `<foreach>` to define query semantics. The service
-boundary must ensure this query is reached only with a non-empty list or a
-deliberate `null` meaning "no ID filter".
+The mapper retains the `ids.size() > 0` guard as defense in depth. That guard
+omits the entire ID predicate for an empty list, which broadens the query. The
+service must short-circuit empty lists before calling the mapper, and any caller
+that bypasses the service must reject empty IDs before query execution. Reserve
+`null` for the deliberate "no ID filter" case.
 
 - Prefer `<where>`, `<set>`, `<trim>`, `<choose>`, and `<foreach>` to manual
   string concatenation.
-- Define the empty-list behavior in the service. Return no rows, skip the
-  query, or apply an explicit false predicate; never rely on `IN ()` behavior.
+- Define the empty-list behavior in the service. Return no rows, skip the query,
+  or apply an explicit false predicate; never let an empty list silently remove
+  the ID predicate or rely on `IN ()` behavior.
 - Keep the allowed shape of dynamic SQL small. If a query has many branches,
   split it into named statements or move carefully selected alternatives into
   separate mapper methods.