diff --git a/README.md b/README.md
index e431fc0f..ff6d1d4b 100644
--- a/README.md
+++ b/README.md
@@ -179,7 +179,7 @@ dbt-coves generate sources -h
 
 ```console
 --flatten-json-fields
-# Flag: flatten model JSON fields
+# Action to perform when JSON fields exist: 'yes', 'no', 'ask' (per file)
 ```
 
 ```console
@@ -478,6 +478,7 @@ generate:
     update_strategy: ask # Action to perform when a property file already exists. Options: update, recreate, fail, ask (per file)
     templates_folder: ".dbt_coves/templates" # Folder where source generation jinja templates are located. Override default templates creating  source_props.yml, source_model_props.yml, and source_model.sql under this folder
     metadata: "metadata.csv" # Path to csv file containing metadata
+    flatten_json_fields: ask
 
   properties:
     destination: "{{model_folder_path}}/{{model_file_name}}.yml" # Where models yml files will be generated
diff --git a/dbt_coves/config/config.py b/dbt_coves/config/config.py
index d2db8f22..ad92f65e 100644
--- a/dbt_coves/config/config.py
+++ b/dbt_coves/config/config.py
@@ -34,7 +34,7 @@ class GenerateSourcesModel(BaseModel):
     templates_folder: Optional[str] = ".dbt_coves/templates"
     metadata: Optional[str] = ""
     no_prompt: Optional[bool] = False
-    flatten_json_fields: Optional[bool] = False
+    flatten_json_fields: Optional[str] = "ask"
     overwrite_staging_models: Optional[bool] = False
     skip_model_props: Optional[bool] = False
 
diff --git a/dbt_coves/tasks/generate/sources.py b/dbt_coves/tasks/generate/sources.py
index 6915d799..6dac84ab 100644
--- a/dbt_coves/tasks/generate/sources.py
+++ b/dbt_coves/tasks/generate/sources.py
@@ -85,7 +85,10 @@ def register_parser(cls, sub_parsers, base_subparser):
             help="Path to csv file containing metadata, i.e. 'metadata.csv'",
         )
         subparser.add_argument(
-            "--flatten-json-fields", help="Flatten JSON fields", action="store_true", default=False
+            "--flatten-json-fields",
+            type=str,
+            choices=["yes", "no", "ask"],
+            help="Action to perform when JSON fields exist:" "'yes', 'no', 'ask' (per file)",
         )
         subparser.add_argument(
             "--overwrite-staging-models",
@@ -135,7 +138,7 @@ def generate(self, rels):
         models_destination = self.get_config_value("models_destination")
         options = {
             "override_all": "Yes" if self.overwrite_sqls else None,
-            "flatten_all": "Yes" if self.flatten_json else None,
+            "flatten_all": "Yes" if self.flatten_json == "yes" else None,
             "model_prop_update_all": False,
             "model_prop_recreate_all": False,
             "source_prop_update_all": False,
@@ -189,7 +192,7 @@ def generate_model(self, relation, destination, options):
         columns = self.adapter.get_columns_in_relation(relation)
         nested_field_type = self.NESTED_FIELD_TYPES.get(self.adapter.__class__.__name__)
         nested = [col.name for col in columns if col.dtype == nested_field_type]
-        if not options["flatten_all"]:
+        if not options["flatten_all"] and self.flatten_json == "ask":
             if nested:
                 field_nlg = "field"
                 flatten_nlg = "flatten it"
diff --git a/dbt_coves/utils/flags.py b/dbt_coves/utils/flags.py
index 5d341d5c..bbfaa20c 100644
--- a/dbt_coves/utils/flags.py
+++ b/dbt_coves/utils/flags.py
@@ -46,7 +46,7 @@ def __init__(self, cli_parser: ArgumentParser) -> None:
                 "templates_folder": None,
                 "metadata": None,
                 "no_prompt": False,
-                "flatten_json_fields": False,
+                "flatten_json_fields": None,
                 "overwrite_staging_models": False,
                 "skip_model_props": False,
             },
@@ -189,7 +189,9 @@ def parse_args(self, cli_args: List[str] = list()) -> None:
                 if self.args.no_prompt:
                     self.generate["sources"]["no_prompt"] = True
                 if self.args.flatten_json_fields:
-                    self.generate["sources"]["flatten_json_fields"] = True
+                    self.generate["sources"][
+                        "flatten_json_fields"
+                    ] = self.args.flatten_json_fields.lower()
                 if self.args.overwrite_staging_models:
                     self.generate["sources"]["overwrite_staging_models"] = True
                 if self.args.skip_model_props:
diff --git a/dbt_coves/utils/jinja.py b/dbt_coves/utils/jinja.py
index 58633763..bb207b0f 100644
--- a/dbt_coves/utils/jinja.py
+++ b/dbt_coves/utils/jinja.py
@@ -4,7 +4,7 @@
 
 
 def add_env_vars(context):
-    context["env_vars"] = os.environ.copy()
+    context["env_var"] = os.environ.copy()
     return context