diff --git a/src/programmers/llm/LlmSchemaProgrammer.ts b/src/programmers/llm/LlmSchemaProgrammer.ts
index 21ec562cc9..60729a1775 100644
--- a/src/programmers/llm/LlmSchemaProgrammer.ts
+++ b/src/programmers/llm/LlmSchemaProgrammer.ts
@@ -1,14 +1,39 @@
 import { ILlmApplication } from "@samchon/openapi";
 import { HttpLlmConverter } from "@samchon/openapi/lib/converters/HttpLlmConverter";
-import { OpenApiV3Converter } from "@samchon/openapi/lib/converters/OpenApiV3Converter";
 
 import { IJsonSchemaCollection } from "../../schemas/json/IJsonSchemaCollection";
 import { Metadata } from "../../schemas/metadata/Metadata";
 
 import { AtomicPredicator } from "../helpers/AtomicPredicator";
+import { json_schema_bigint } from "../internal/json_schema_bigint";
+import { json_schema_boolean } from "../internal/json_schema_boolean";
+import { json_schema_native } from "../internal/json_schema_native";
+import { json_schema_number } from "../internal/json_schema_number";
+import { json_schema_string } from "../internal/json_schema_string";
 import { JsonSchemasProgrammer } from "../json/JsonSchemasProgrammer";
 
 export namespace LlmSchemaProgrammer {
+  export const write = <Model extends ILlmApplication.Model>(props: {
+    model: Model;
+    metadata: Metadata;
+  }): ILlmApplication.ModelSchema[Model] => {
+    const collection: IJsonSchemaCollection<"3.1"> =
+      JsonSchemasProgrammer.write({
+        version: "3.1",
+        metadatas: [props.metadata],
+      });
+    const schema: ILlmApplication.ModelSchema[Model] | null =
+      HttpLlmConverter.schema({
+        model: props.model,
+        components: collection.components,
+        schema: collection.schemas[0]!,
+        recursive: 3,
+      });
+    if (schema === null)
+      throw new Error("Failed to convert JSON schema to LLM schema.");
+    return schema;
+  };
+
   export const validate =
     (model: ILlmApplication.Model) =>
     (metadata: Metadata): string[] => {
@@ -37,18 +62,8 @@ export namespace LlmSchemaProgrammer {
           native.name !== "File"
         )
           output.push(`LLM schema does not support ${native.name} type.`);
-      if (model === "gemini") {
-        try {
-          const {
-            schemas: [schema],
-          } = JsonSchemasProgrammer.write({
-            version: "3.0",
-            metadatas: [metadata],
-          });
-          if (OpenApiV3Converter.TypeChecker.isOneOf(schema!))
-            output.push("Gemini model does not support the union type.");
-        } catch {}
-      }
+      if (model === "gemini" && size(metadata) > 1)
+        output.push("Gemini model does not support the union type.");
       // if (
       //   metadata.aliases.some((a) => a.type.recursive) ||
       //   metadata.arrays.some((a) => a.type.recursive) ||
@@ -58,25 +73,42 @@ export namespace LlmSchemaProgrammer {
       //   output.push("LLM schema does not support recursive type.");
       return output;
     };
-
-  export const write = <Model extends ILlmApplication.Model>(props: {
-    model: Model;
-    metadata: Metadata;
-  }): ILlmApplication.ModelSchema[Model] => {
-    const collection: IJsonSchemaCollection<"3.1"> =
-      JsonSchemasProgrammer.write({
-        version: "3.1",
-        metadatas: [props.metadata],
-      });
-    const schema: ILlmApplication.ModelSchema[Model] | null =
-      HttpLlmConverter.schema({
-        model: props.model,
-        components: collection.components,
-        schema: collection.schemas[0]!,
-        recursive: 3,
-      });
-    if (schema === null)
-      throw new Error("Failed to convert JSON schema to LLM schema.");
-    return schema;
-  };
 }
+
+const size = (metadata: Metadata): number =>
+  (metadata.escaped ? size(metadata.escaped.returns) : 0) +
+  metadata.aliases.length +
+  metadata.objects.length +
+  metadata.arrays.length +
+  metadata.tuples.length +
+  (metadata.maps.length ? 1 : 0) +
+  (metadata.sets.length ? 1 : 0) +
+  metadata.atomics
+    .map((a) =>
+      a.type === "boolean"
+        ? json_schema_boolean(a).length
+        : a.type === "bigint"
+          ? json_schema_bigint(a).length
+          : a.type === "number"
+            ? json_schema_number(a).length
+            : json_schema_string(a).length,
+    )
+    .reduce((a, b) => a + b, 0) +
+  metadata.constants.filter(
+    (c) => metadata.atomics.some((a) => a.type === c.type) === false,
+  ).length +
+  metadata.templates.length +
+  metadata.natives
+    .filter(
+      (n) =>
+        metadata.atomics.some((a) => a.type === n.name) === false &&
+        metadata.constants.some((c) => c.type === n.name) === false,
+    )
+    .map(
+      (n) =>
+        json_schema_native({
+          components: {},
+          native: n,
+        }).length,
+    )
+    .reduce((a, b) => a + b, 0);