diff --git a/src/parser/extract-tools.ts b/src/parser/extract-tools.ts
index 8816095..4c57050 100644
--- a/src/parser/extract-tools.ts
+++ b/src/parser/extract-tools.ts
@@ -153,10 +153,14 @@ export function generateInputSchemaAndDetails(operation: OpenAPIV3.OperationObje
 }
 
 /**
- * Maps an OpenAPI schema to a JSON Schema
+ * Converts an OpenAPI schema or reference object to a JSON Schema representation.
  *
- * @param schema OpenAPI schema object or reference
- * @returns JSON Schema representation
+ * Handles composite schemas (`oneOf`, `anyOf`, `allOf`) by merging subschemas and combining enum values. Removes OpenAPI-specific properties and adjusts types for JSON Schema compatibility, including handling of nullable fields. Recursively processes nested object properties and array items.
+ *
+ * @param schema - The OpenAPI schema object or reference to convert.
+ * @returns The corresponding JSON Schema object or boolean schema.
+ *
+ * @remark If a `$ref` reference cannot be resolved, returns a generic object schema and logs a warning.
  */
 export function mapOpenApiSchemaToJsonSchema(
   schema: OpenAPIV3.SchemaObject | OpenAPIV3.ReferenceObject
@@ -171,7 +175,35 @@ export function mapOpenApiSchemaToJsonSchema(
   if (typeof schema === 'boolean') return schema;
 
   // Create a copy of the schema to modify
-  const jsonSchema: JSONSchema7 = { ...schema } as any;
+  let jsonSchema: JSONSchema7 = { ...schema } as any;
+
+  if (schema.oneOf || schema.anyOf || schema.allOf) {
+    const oneSchema = structuredClone(schema.oneOf || schema.anyOf || schema.allOf);
+
+    if (oneSchema) {
+      const combinedSchema = mapOpenApiSchemaToJsonSchema(oneSchema[0]);
+      
+      for (let i = 1; i < oneSchema.length; i++) {
+        const mappedSubSchema = mapOpenApiSchemaToJsonSchema(oneSchema[i]);
+        if (typeof mappedSubSchema === 'object' && typeof combinedSchema === 'object') {
+          // Handle enum values
+          if (mappedSubSchema.enum) {
+            if (!combinedSchema.enum) {
+              combinedSchema.enum = [];
+            }
+            // Combine enum values from both schemas
+            const uniqueEnums = new Set([
+              ...combinedSchema.enum,
+              ...(mappedSubSchema.enum || [])
+            ]);
+            combinedSchema.enum = Array.from(uniqueEnums);
+          }
+        }
+      }
+
+      jsonSchema = combinedSchema as JSONSchema7;
+    }
+  }
 
   // Convert integer type to number (JSON Schema compatible)
   if (schema.type === 'integer') jsonSchema.type = 'number';