diff --git a/skills/objectstack-query/SKILL.md b/skills/objectstack-query/SKILL.md
index f68b4f46b1..34e0d0142d 100644
--- a/skills/objectstack-query/SKILL.md
+++ b/skills/objectstack-query/SKILL.md
@@ -154,7 +154,7 @@ The simplest filter — field equals value:
 | Operator | Purpose | SQL / NoSQL |
 |:---------|:--------|:------------|
 | `$null` | Is null check | `IS NULL` / `IS NOT NULL` |
-| `$exists` | Field exists (NoSQL) | MongoDB `$exists` |
+| `$exists` | Has a value | `IS NOT NULL` / `IS NULL` |
 
 ```typescript
 { where: { deleted_at: { $null: true } } }
diff --git a/skills/objectstack-query/rules/filters.md b/skills/objectstack-query/rules/filters.md
index 08c6b428a5..30db6c49a7 100644
--- a/skills/objectstack-query/rules/filters.md
+++ b/skills/objectstack-query/rules/filters.md
@@ -20,7 +20,7 @@ Comprehensive guide for building ObjectStack query filters.
 | String | `$startsWith` | `LIKE ?%` | `{ code: { $startsWith: 'PRJ-' } }` |
 | String | `$endsWith` | `LIKE %?` | `{ file: { $endsWith: '.pdf' } }` |
 | Null | `$null` | `IS NULL` / `IS NOT NULL` | `{ deleted_at: { $null: true } }` |
-| Existence | `$exists` | (NoSQL) `$exists` | `{ metadata: { $exists: true } }` |
+| Null | `$exists` | `IS NOT NULL` / `IS NULL` | `{ metadata: { $exists: true } }` |
 
 ## Implicit Equality (Shorthand)