diff --git a/GEMINI.md b/GEMINI.md
index 7dd7dd5..3a06a30 100644
--- a/GEMINI.md
+++ b/GEMINI.md
@@ -234,7 +234,7 @@ The Queryer transforms Postgres into a pre-compiled Semantic Query Engine, desig
 *   **Dynamic Filtering**: Binds parameters natively through `cue.filters` objects. The queryer enforces a strict, structured, MongoDB-style operator syntax to map incoming JSON request constraints directly to their originating structural table columns. Filters support both flat path notation (e.g., `"contacts/is_primary": {...}`) and deeply nested recursive JSON structures (e.g., `{"contacts": {"is_primary": {...}}}`). The queryer recursively traverses and flattens these structures at AST compilation time.
     *   **Equality / Inequality**: `{"$eq": value}`, `{"$ne": value}` automatically map to `=` and `!=`.
     *   **Comparison**: `{"$gt": ...}`, `{"$gte": ...}`, `{"$lt": ...}`, `{"$lte": ...}` directly compile to Postgres comparison operators (`> `, `>=`, `<`, `<=`).
-    *   **Array Inclusion**: `{"$in": [values]}`, `{"$nin": [values]}` use native `jsonb_array_elements_text()` bindings to enforce `IN` and `NOT IN` logic without runtime SQL injection risks.
+    *   **Array Inclusion**: `{"$of": [values]}`, `{"$nof": [values]}` use native `jsonb_array_elements_text()` bindings to enforce `IN` and `NOT IN` logic without runtime SQL injection risks.
     *   **Text Matching (ILIKE)**: Evaluates `$eq` or `$ne` against string fields containing the `%` character natively into Postgres `ILIKE` and `NOT ILIKE` partial substring matches.
     *   **Type Casting**: Safely resolves dynamic combinations by casting values instantly into the physical database types mapped in the schema (e.g. parsing `uuid` bindings to `::uuid`, formatting DateTimes to `::timestamptz`, and numbers to `::numeric`).
 *   **Polymorphic SQL Generation (`family`)**: Compiles `family` properties by analyzing the **Physical Database Variations**, *not* the schema descendants.
diff --git a/fixtures/queryer.json b/fixtures/queryer.json
index d6eff57..997f2d0 100644
--- a/fixtures/queryer.json
+++ b/fixtures/queryer.json
@@ -1199,10 +1199,10 @@
           "id": {
             "$eq": "123e4567-e89b-12d3-a456-426614174000",
             "$ne": "123e4567-e89b-12d3-a456-426614174001",
-            "$in": [
+            "$of": [
               "123e4567-e89b-12d3-a456-426614174000"
             ],
-            "$nin": [
+            "$nof": [
               "123e4567-e89b-12d3-a456-426614174001"
             ]
           },
@@ -1241,9 +1241,9 @@
               "  AND entity_1.created_at <= ($7#>>'{}')::timestamptz",
               "  AND entity_1.created_at != ($8#>>'{}')::timestamptz",
               "  AND entity_1.id = ($9#>>'{}')::uuid",
-              "  AND entity_1.id IN (SELECT value::uuid FROM jsonb_array_elements_text(($10#>>'{}')::jsonb))",
-              "  AND entity_1.id != ($11#>>'{}')::uuid",
-              "  AND entity_1.id NOT IN (SELECT value::uuid FROM jsonb_array_elements_text(($12#>>'{}')::jsonb))",
+              "  AND entity_1.id != ($10#>>'{}')::uuid",
+              "  AND entity_1.id NOT IN (SELECT value::uuid FROM jsonb_array_elements_text(($11#>>'{}')::jsonb))",
+              "  AND entity_1.id IN (SELECT value::uuid FROM jsonb_array_elements_text(($12#>>'{}')::jsonb))",
               ")))"
             ]
           ]
@@ -1448,14 +1448,14 @@
             "$eq": 30,
             "$gt": 20,
             "$gte": 20,
-            "$in": [
+            "$of": [
               30,
               40
             ],
             "$lt": 50,
             "$lte": 50,
             "$ne": 25,
-            "$nin": [
+            "$nof": [
               1,
               2
             ]
@@ -1481,24 +1481,24 @@
             "$eq": "Jane%",
             "$gt": "A",
             "$gte": "A",
-            "$in": [
+            "$of": [
               "Jane",
               "John"
             ],
             "$lt": "Z",
             "$lte": "Z",
             "$ne": "Doe",
-            "$nin": [
+            "$nof": [
               "Bob"
             ]
           },
           "id": {
             "$eq": "00000000-0000-0000-0000-000000000001",
-            "$in": [
+            "$of": [
               "00000000-0000-0000-0000-000000000001"
             ],
             "$ne": "00000000-0000-0000-0000-000000000002",
-            "$nin": [
+            "$nof": [
               "00000000-0000-0000-0000-000000000002"
             ]
           },
@@ -1677,11 +1677,11 @@
               "  AND person_1.age = ($1#>>'{}')::numeric",
               "  AND person_1.age > ($2#>>'{}')::numeric",
               "  AND person_1.age >= ($3#>>'{}')::numeric",
-              "  AND person_1.age IN (SELECT value::numeric FROM jsonb_array_elements_text(($4#>>'{}')::jsonb))",
-              "  AND person_1.age < ($5#>>'{}')::numeric",
-              "  AND person_1.age <= ($6#>>'{}')::numeric",
-              "  AND person_1.age != ($7#>>'{}')::numeric",
-              "  AND person_1.age NOT IN (SELECT value::numeric FROM jsonb_array_elements_text(($8#>>'{}')::jsonb))",
+              "  AND person_1.age < ($4#>>'{}')::numeric",
+              "  AND person_1.age <= ($5#>>'{}')::numeric",
+              "  AND person_1.age != ($6#>>'{}')::numeric",
+              "  AND person_1.age NOT IN (SELECT value::numeric FROM jsonb_array_elements_text(($7#>>'{}')::jsonb))",
+              "  AND person_1.age IN (SELECT value::numeric FROM jsonb_array_elements_text(($8#>>'{}')::jsonb))",
               "  AND entity_3.archived = ($9#>>'{}')::boolean",
               "  AND entity_3.archived != ($10#>>'{}')::boolean",
               "  AND entity_3.created_at = ($12#>>'{}')::timestamptz",
@@ -1693,15 +1693,15 @@
               "  AND person_1.first_name ILIKE $18#>>'{}'",
               "  AND person_1.first_name > ($19#>>'{}')",
               "  AND person_1.first_name >= ($20#>>'{}')",
-              "  AND person_1.first_name IN (SELECT value FROM jsonb_array_elements_text(($21#>>'{}')::jsonb))",
-              "  AND person_1.first_name < ($22#>>'{}')",
-              "  AND person_1.first_name <= ($23#>>'{}')",
-              "  AND person_1.first_name NOT ILIKE $24#>>'{}'",
-              "  AND person_1.first_name NOT IN (SELECT value FROM jsonb_array_elements_text(($25#>>'{}')::jsonb))",
+              "  AND person_1.first_name < ($21#>>'{}')",
+              "  AND person_1.first_name <= ($22#>>'{}')",
+              "  AND person_1.first_name NOT ILIKE $23#>>'{}'",
+              "  AND person_1.first_name NOT IN (SELECT value FROM jsonb_array_elements_text(($24#>>'{}')::jsonb))",
+              "  AND person_1.first_name IN (SELECT value FROM jsonb_array_elements_text(($25#>>'{}')::jsonb))",
               "  AND entity_3.id = ($26#>>'{}')::uuid",
-              "  AND entity_3.id IN (SELECT value::uuid FROM jsonb_array_elements_text(($27#>>'{}')::jsonb))",
-              "  AND entity_3.id != ($28#>>'{}')::uuid",
-              "  AND entity_3.id NOT IN (SELECT value::uuid FROM jsonb_array_elements_text(($29#>>'{}')::jsonb))",
+              "  AND entity_3.id != ($27#>>'{}')::uuid",
+              "  AND entity_3.id NOT IN (SELECT value::uuid FROM jsonb_array_elements_text(($28#>>'{}')::jsonb))",
+              "  AND entity_3.id IN (SELECT value::uuid FROM jsonb_array_elements_text(($29#>>'{}')::jsonb))",
               "  AND person_1.last_name ILIKE $30#>>'{}'",
               "  AND person_1.last_name NOT ILIKE $31#>>'{}')))"
             ]
diff --git a/src/queryer/compiler.rs b/src/queryer/compiler.rs
index 6bfeb0e..51a157a 100644
--- a/src/queryer/compiler.rs
+++ b/src/queryer/compiler.rs
@@ -717,8 +717,8 @@ impl<'a> Compiler<'a> {
       let param_index = i + 1;
       let p_val = format!("${}#>>'{{}}'", param_index);
 
-      if op == "$in" || op == "$nin" {
-        let sql_op = if op == "$in" { "IN" } else { "NOT IN" };
+      if op == "$of" || op == "$nof" {
+        let sql_op = if op == "$of" { "IN" } else { "NOT IN" };
         let subquery = format!(
           "(SELECT value{} FROM jsonb_array_elements_text(({})::jsonb))",
           cast, p_val