diff --git a/modules/ai-applications/README.md b/modules/ai-applications/README.md
index c31e09e1e..c9abd12c1 100644
--- a/modules/ai-applications/README.md
+++ b/modules/ai-applications/README.md
@@ -236,8 +236,8 @@ module "ai-applications" {
 |---|---|:---:|:---:|:---:|
 | [name](variables.tf#L159) | The name of the resources. | <code>string</code> | ✓ |  |
 | [project_id](variables.tf#L165) | The ID of the project where the data stores and the agents will be created. | <code>string</code> | ✓ |  |
-| [data_stores_configs](variables.tf#L17) | The ai-applications datastore configurations. | <code title="map&#40;object&#40;&#123;&#10;  advanced_site_search_config &#61; optional&#40;object&#40;&#123;&#10;    disable_initial_index     &#61; optional&#40;bool&#41;&#10;    disable_automatic_refresh &#61; optional&#40;bool&#41;&#10;  &#125;&#41;&#41;&#10;  content_config              &#61; optional&#40;string, &#34;NO_CONTENT&#34;&#41;&#10;  create_advanced_site_search &#61; optional&#40;bool&#41;&#10;  display_name                &#61; optional&#40;string&#41;&#10;  document_processing_config &#61; optional&#40;object&#40;&#123;&#10;    chunking_config &#61; optional&#40;object&#40;&#123;&#10;      layout_based_chunking_config &#61; optional&#40;object&#40;&#123;&#10;        chunk_size                &#61; optional&#40;number&#41;&#10;        include_ancestor_headings &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#10;    default_parsing_config &#61; optional&#40;object&#40;&#123;&#10;      digital_parsing_config &#61; optional&#40;bool&#41;&#10;      layout_parsing_config  &#61; optional&#40;bool&#41;&#10;      ocr_parsing_config &#61; optional&#40;object&#40;&#123;&#10;        use_native_text &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#10;    parsing_config_overrides &#61; map&#40;object&#40;&#123;&#10;      digital_parsing_config &#61; optional&#40;bool&#41;&#10;      layout_parsing_config  &#61; optional&#40;bool&#41;&#10;      ocr_parsing_config &#61; optional&#40;object&#40;&#123;&#10;        use_native_text &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#41;&#10;  industry_vertical            &#61; optional&#40;string, &#34;GENERIC&#34;&#41;&#10;  json_schema                  &#61; optional&#40;string&#41;&#10;  location                     &#61; optional&#40;string&#41;&#10;  skip_default_schema_creation &#61; optional&#40;bool&#41;&#10;  solution_types               &#61; optional&#40;list&#40;string&#41;&#41;&#10;  sites_search_config &#61; optional&#40;object&#40;&#123;&#10;    sitemap_uri &#61; optional&#40;string&#41;&#10;    target_sites &#61; map&#40;object&#40;&#123;&#10;      provided_uri_pattern &#61; string&#10;      exact_match          &#61; optional&#40;bool, false&#41;&#10;      type                 &#61; optional&#40;string, &#34;INCLUDE&#34;&#41;&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
-| [engines_configs](variables.tf#L112) | The ai-applications engines configurations. | <code title="map&#40;object&#40;&#123;&#10;  data_store_ids &#61; list&#40;string&#41;&#10;  collection_id  &#61; optional&#40;string, &#34;default_collection&#34;&#41;&#10;  chat_engine_config &#61; optional&#40;object&#40;&#123;&#10;    allow_cross_region       &#61; optional&#40;bool&#41;&#10;    business                 &#61; optional&#40;string&#41;&#10;    company_name             &#61; optional&#40;string&#41;&#10;    default_language_code    &#61; optional&#40;string&#41;&#10;    dialogflow_agent_to_link &#61; optional&#40;string&#41;&#10;    time_zone                &#61; optional&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;  industry_vertical &#61; optional&#40;string&#41;&#10;  location          &#61; optional&#40;string&#41;&#10;  search_engine_config &#61; optional&#40;object&#40;&#123;&#10;    search_add_ons &#61; optional&#40;list&#40;string&#41;, &#91;&#93;&#41;&#10;    search_tier    &#61; optional&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
+| [data_stores_configs](variables.tf#L17) | The ai-applications datastore configurations. | <code title="map&#40;object&#40;&#123;&#10;  advanced_site_search_config &#61; optional&#40;object&#40;&#123;&#10;    disable_initial_index     &#61; optional&#40;bool&#41;&#10;    disable_automatic_refresh &#61; optional&#40;bool&#41;&#10;  &#125;&#41;&#41;&#10;  content_config              &#61; optional&#40;string, &#34;NO_CONTENT&#34;&#41;&#10;  create_advanced_site_search &#61; optional&#40;bool&#41;&#10;  display_name                &#61; optional&#40;string&#41;&#10;  document_processing_config &#61; optional&#40;object&#40;&#123;&#10;    chunking_config &#61; optional&#40;object&#40;&#123;&#10;      layout_based_chunking_config &#61; optional&#40;object&#40;&#123;&#10;        chunk_size                &#61; optional&#40;number&#41;&#10;        include_ancestor_headings &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#10;    default_parsing_config &#61; optional&#40;object&#40;&#123;&#10;      digital_parsing_config &#61; optional&#40;bool&#41;&#10;      layout_parsing_config  &#61; optional&#40;bool&#41;&#10;      ocr_parsing_config &#61; optional&#40;object&#40;&#123;&#10;        use_native_text &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#10;    parsing_config_overrides &#61; optional&#40;map&#40;object&#40;&#123;&#10;      digital_parsing_config &#61; optional&#40;bool&#41;&#10;      layout_parsing_config  &#61; optional&#40;bool&#41;&#10;      ocr_parsing_config &#61; optional&#40;object&#40;&#123;&#10;        use_native_text &#61; optional&#40;bool&#41;&#10;      &#125;&#41;&#41;&#10;    &#125;&#41;&#41;&#41;&#10;  &#125;&#41;&#41;&#10;  industry_vertical            &#61; optional&#40;string, &#34;GENERIC&#34;&#41;&#10;  json_schema                  &#61; optional&#40;string&#41;&#10;  location                     &#61; optional&#40;string&#41;&#10;  skip_default_schema_creation &#61; optional&#40;bool&#41;&#10;  solution_types               &#61; optional&#40;list&#40;string&#41;&#41;&#10;  sites_search_config &#61; optional&#40;object&#40;&#123;&#10;    sitemap_uri &#61; optional&#40;string&#41;&#10;    target_sites &#61; map&#40;object&#40;&#123;&#10;      provided_uri_pattern &#61; string&#10;      exact_match          &#61; optional&#40;bool, false&#41;&#10;      type                 &#61; optional&#40;string, &#34;INCLUDE&#34;&#41;&#10;    &#125;&#41;&#41;&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
+| [engines_configs](variables.tf#L112) | The ai-applications engines configurations. | <code title="map&#40;object&#40;&#123;&#10;  data_store_ids &#61; list&#40;string&#41;&#10;  collection_id  &#61; optional&#40;string, &#34;default_collection&#34;&#41;&#10;  chat_engine_config &#61; optional&#40;object&#40;&#123;&#10;    allow_cross_region       &#61; optional&#40;bool, null&#41;&#10;    business                 &#61; optional&#40;string&#41;&#10;    company_name             &#61; optional&#40;string&#41;&#10;    default_language_code    &#61; optional&#40;string&#41;&#10;    dialogflow_agent_to_link &#61; optional&#40;string&#41;&#10;    time_zone                &#61; optional&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;  industry_vertical &#61; optional&#40;string&#41;&#10;  location          &#61; optional&#40;string&#41;&#10;  search_engine_config &#61; optional&#40;object&#40;&#123;&#10;    search_add_ons &#61; optional&#40;list&#40;string&#41;, &#91;&#93;&#41;&#10;    search_tier    &#61; optional&#40;string&#41;&#10;  &#125;&#41;&#41;&#10;&#125;&#41;&#41;">map&#40;object&#40;&#123;&#8230;&#125;&#41;&#41;</code> |  | <code>&#123;&#125;</code> |
 | [location](variables.tf#L153) | Location where the data stores and agents will be created. | <code>string</code> |  | <code>&#34;global&#34;</code> |
 
 ## Outputs
diff --git a/modules/ai-applications/engines.tf b/modules/ai-applications/engines.tf
index 4c84f9b79..02b69cc74 100644
--- a/modules/ai-applications/engines.tf
+++ b/modules/ai-applications/engines.tf
@@ -56,8 +56,12 @@ resource "google_discovery_engine_chat_engine" "default" {
     }
   }
 
-  common_config {
-    company_name = each.value.chat_engine_config.company_name
+  dynamic "common_config" {
+    for_each = each.value.chat_engine_config.company_name == null ? [] : [""]
+
+    content {
+      company_name = each.value.chat_engine_config.company_name
+    }
   }
 }
 
diff --git a/modules/ai-applications/main.tf b/modules/ai-applications/main.tf
index 49ec255cb..1443aef67 100644
--- a/modules/ai-applications/main.tf
+++ b/modules/ai-applications/main.tf
@@ -123,7 +123,7 @@ resource "google_discovery_engine_data_store" "default" {
       }
 
       dynamic "parsing_config_overrides" {
-        for_each = each.value.document_processing_config.parsing_config_overrides
+        for_each = coalesce(each.value.document_processing_config.parsing_config_overrides, {})
 
         content {
           file_type = parsing_config_overrides.key
diff --git a/modules/ai-applications/variables.tf b/modules/ai-applications/variables.tf
index 6739b44ed..37ce13efa 100644
--- a/modules/ai-applications/variables.tf
+++ b/modules/ai-applications/variables.tf
@@ -39,13 +39,13 @@ variable "data_stores_configs" {
         }))
       }))
       # Accepted keys: docx, html, pdf
-      parsing_config_overrides = map(object({
+      parsing_config_overrides = optional(map(object({
         digital_parsing_config = optional(bool)
         layout_parsing_config  = optional(bool)
         ocr_parsing_config = optional(object({
           use_native_text = optional(bool)
         }))
-      }))
+      })))
     }))
     industry_vertical            = optional(string, "GENERIC")
     json_schema                  = optional(string)
@@ -115,7 +115,7 @@ variable "engines_configs" {
     data_store_ids = list(string)
     collection_id  = optional(string, "default_collection")
     chat_engine_config = optional(object({
-      allow_cross_region       = optional(bool)
+      allow_cross_region       = optional(bool, null)
       business                 = optional(string)
       company_name             = optional(string)
       default_language_code    = optional(string)