diff --git a/docker/Dockerfile b/docker/Dockerfile
index 4a03a82..e60274c 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -39,11 +39,11 @@ RUN apt-get update \
 
 # Adapt pip install option based on distro (technically ubuntu version)
 RUN if [ "$ROS_DISTRO" = "humble" ]; then \
-        pip install openai; \
+        pip install openai ollama; \
     elif [ "$ROS_DISTRO" = "iron" ]; then \
-        pip install openai; \
+        pip install openai ollama; \
     else \
-        pip install openai --break-system-packages; \
+        pip install openai ollama --break-system-packages; \
     fi
 
 # Build and source colcon workspace
diff --git a/ros2ai/api/__init__.py b/ros2ai/api/__init__.py
index 6dbd6fe..25e225a 100644
--- a/ros2ai/api/__init__.py
+++ b/ros2ai/api/__init__.py
@@ -20,20 +20,24 @@
 import ros2ai.api.constants as constants
 
 def add_global_arguments(parser):
-        # add global arguments
+    # add global arguments
+    default_models = constants.ROS_OPENAI_DEFAULT_MODEL + ', ' + constants.ROS_OLLAMA_DEFAULT_MODEL
     parser.add_argument(
         '-m', '--model', metavar='<model>', type=str, default=None,
-        help=f'Set OpenAI API model (default %(default)s) or '
+        help=f'Set OpenAI API model (e.g {default_models}) or '
             f'use {constants.ROS_OPENAI_MODEL_NAME_ENV_VAR} environment variable. (argument prevails)')
     parser.add_argument(
         '-u', '--url', metavar='<url>', type=str, default=None,
-        help='Set OpenAI API endpoint URL (default %(default)s) or '
+        help=f'Set OpenAI API endpoint URL (e.g {constants.ROS_OPENAI_DEFAULT_ENDPOINT}) or '
             f'use {constants.ROS_OPENAI_ENDPOINT_ENV_VAR} environment variable. (argument prevails)')
     parser.add_argument(
         '-t', '--token', metavar='<token>', type=int, default=None,
         help='Set OpenAI API maximum token (default %(default)s)')
 
 
+# TODO(@fujitatomoya): replace curl command based API call into python API.
+#  There is no need to call http request bypass provided Python API calls if available.
+#  curl https://api.openai.com/v1/models -H "Authorization: Bearer XXXXX"
 def curl_get_request(url, headers=None) -> Tuple[bool, Optional[List[str]]]:
     response_list = []
     # only supports basic curl subprocess command
@@ -63,3 +67,28 @@ def curl_get_request(url, headers=None) -> Tuple[bool, Optional[List[str]]]:
     except Exception as e:
         print(f"Error executing curl command: {e}")
         return False, None
+
+
+# curl http://localhost:11434/api/tags
+def ollama_get_models(url, headers=None) -> Tuple[bool, Optional[List[str]]]:
+    # only supports basic curl subprocess command
+    curl_cmd = ["curl", url]
+
+    if headers:
+        for key, value in headers.items():
+            curl_cmd.extend(["-H", f"{key}: {value}"])
+
+    try:
+        # execute the curl command in subprocess
+        result = subprocess.run(curl_cmd, capture_output=True, text=True, check=True)
+        if result.returncode == 0:
+            data = json.loads(result.stdout)
+            response_list = [d.get('name') + ' ' + d.get('modified_at') for d in data['models']]
+            return True, response_list
+        else:
+            # this means, subprocess returns failure
+            print(result.stdout)
+            return False, None
+    except Exception as e:
+        print(f"Error executing curl command: {e}")
+        return False, None
diff --git a/ros2ai/api/config.py b/ros2ai/api/config.py
index e2be592..55e5e11 100644
--- a/ros2ai/api/config.py
+++ b/ros2ai/api/config.py
@@ -23,10 +23,7 @@ def get_api_key() -> str:
     """
     Get OpenAI API Key from OPENAI_API_KEY environment variable.
 
-    OpenAI API Key must be set by ros2ai user with OPENAI_API_KEY environment variable.
-
-    :return: string of OpenAI API Key.
-    :raises: if OPENAI_API_KEY is not set.
+    :return: string of OpenAI API Key otherwise return None.
     """
     key_name = os.environ.get(constants.ROS_OPENAI_API_KEY_ENV_VAR, "None")
     return key_name
@@ -35,13 +32,11 @@ def get_ai_model() -> str:
     """
     Get OpenAI Model from OPENAI_MODEL_NAME environment variable.
 
-    OpenAI Model is optional, in default to gpt-4o
-
     :return: string of OpenAI Model.
     """
     model_name = os.environ.get(constants.ROS_OPENAI_MODEL_NAME_ENV_VAR)
     if not model_name:
-        # TODO(@fujitatomoya):better to print info here that using default model.
+        print('AI model is not set, defaults to ' + constants.ROS_OPENAI_DEFAULT_MODEL)
         return constants.ROS_OPENAI_DEFAULT_MODEL
     else:
         return model_name
@@ -50,13 +45,12 @@ def get_endpoint_url() -> str:
     """
     Get OpenAI API service endpoint URL from OPENAI_ENDPOINT environment variable.
 
-    OpenAI API service endpoint URL is optional, in default fallback to openai.
-
     :return: string of OpenAI API service endpoint URL, could be None.
     """
     url = os.environ.get(constants.ROS_OPENAI_ENDPOINT_ENV_VAR)
     # TODO(@fujitatomoya):check if that is valid url before return.
     if not url:
+        print('AI model is not set, defaults to ' + constants.ROS_OPENAI_DEFAULT_ENDPOINT)
         return constants.ROS_OPENAI_DEFAULT_ENDPOINT
     else:
         return url
@@ -134,7 +128,7 @@ def is_api_key_valid(self):
                 messages = [
                     {
                         "role": "user",
-                        "content": "Are you in service?",
+                        "content": "Are you available?",
                     },
                 ],
                 temperature = self.get_value('api_temperature'),
diff --git a/ros2ai/api/constants.py b/ros2ai/api/constants.py
index 9b3e606..b6e89b1 100644
--- a/ros2ai/api/constants.py
+++ b/ros2ai/api/constants.py
@@ -12,12 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This is only required when actually accessing api.openai.com
 ROS_OPENAI_API_KEY_ENV_VAR = 'OPENAI_API_KEY'
 
 ROS_OPENAI_DEFAULT_MODEL = 'gpt-4o'
+ROS_OLLAMA_DEFAULT_MODEL = 'llama3.1'
+
 ROS_OPENAI_MODEL_NAME_ENV_VAR = 'OPENAI_MODEL_NAME'
 
 ROS_OPENAI_DEFAULT_ENDPOINT = 'https://api.openai.com/v1'
+ROS_OLLAMA_DEFAULT_ENDPOINT = 'http://localhost:11434/v1'
+
 ROS_OPENAI_ENDPOINT_ENV_VAR = 'OPENAI_ENDPOINT'
 
 # The system message helps set the behavior of the assistant.
diff --git a/ros2ai/api/utils.py b/ros2ai/api/utils.py
index 4062b74..c82b781 100644
--- a/ros2ai/api/utils.py
+++ b/ros2ai/api/utils.py
@@ -79,8 +79,8 @@ def get_ros_distro() -> str:
     """
     distro = os.environ.get('ROS_DISTRO')
     if not distro:
-        print('ROS_DISTRO env value is not set.')
-        return None
+        print('ROS_DISTRO env value is not set, use rolling')
+        return 'rolling'
     return distro.lower()
 
 def truncate_before_substring(*, original, substring) -> str:
diff --git a/ros2ai/verb/exec.py b/ros2ai/verb/exec.py
index 0e543d9..020dd19 100644
--- a/ros2ai/verb/exec.py
+++ b/ros2ai/verb/exec.py
@@ -56,8 +56,6 @@ def main(self, *, args):
             print('Please insert your request! (I am not AI)')
 
         distro = get_ros_distro()
-        if distro is None:
-            distro = 'rolling' # fallback to rolling in default
         system_role = get_role_system(default_role_system=ROLE_SYSTEM_EXEC_DEFAULT)
         if args.role and args.role != system_role:
             system_role = args.role
diff --git a/ros2ai/verb/query.py b/ros2ai/verb/query.py
index 1e27012..6e25a20 100644
--- a/ros2ai/verb/query.py
+++ b/ros2ai/verb/query.py
@@ -57,8 +57,6 @@ def main(self, *, args):
             print('Dont be shy, put some questions! (I am not AI)') 
 
         distro = get_ros_distro()
-        if distro is None:
-            distro = 'rolling' # fallback to rolling in default
         system_role = get_role_system(default_role_system=ROLE_SYSTEM_QUERY_DEFAULT)
         if args.role and args.role != system_role:
             system_role = args.role
diff --git a/scripts/docker_release.sh b/scripts/docker_release.sh
index 1cd6a83..e5a15e2 100755
--- a/scripts/docker_release.sh
+++ b/scripts/docker_release.sh
@@ -40,6 +40,7 @@ function print_usage() {
 }
 
 function exit_trap() {
+    # shellcheck disable=SC2317  # Don't warn about unreachable commands in this function
     if [ $? != 0 ]; then
         echo "Command [$BASH_COMMAND] is failed"
         exit 1
@@ -138,7 +139,8 @@ fi
 
 # verifying images
 if [ "$verify_image" = true ]; then
-    # TODO@fujitatomoya: need to check if OPENAI_API_KEY env is set, otherwise return error
+    # TODO@fujitatomoya: need to check if ollama system service is running OR
+    #  check if OPENAI_API_KEY env is set, otherwise return error
     verify_images
 fi
 
diff --git a/scripts/github_workflows.sh b/scripts/github_workflows.sh
index e633ca1..a732c55 100755
--- a/scripts/github_workflows.sh
+++ b/scripts/github_workflows.sh
@@ -21,6 +21,7 @@ function mark {
 }
 
 function exit_trap() {
+    # shellcheck disable=SC2317  # Don't warn about unreachable commands in this function
     if [ $? != 0 ]; then
         echo "Command [$BASH_COMMAND] is failed"
         exit 1
@@ -40,9 +41,9 @@ function install_prerequisites () {
     # TODO@fujitatomoya: should install openai via package.xml
     apt install -y pip
     if [ $UBUNTU_VERSION == "24.04" ]; then
-        pip install openai --break-system-packages
+        pip install openai ollama --break-system-packages
     else
-        pip install openai
+        pip install openai ollama
     fi
     #apt install -y ros-${ROS_DISTRO}-desktop --no-install-recommends
     cd $there
@@ -62,6 +63,7 @@ function build_colcon_package () {
     source /opt/ros/${ROS_DISTRO}/setup.bash
     cd ${COLCON_WORKSPACE}
     # TODO@fujitatomoya: extend this with `colcon test`.
+    #  Once ollama is supported, we can integrate `verification.sh` via github workflow as 1st.
     colcon build --symlink-install --packages-select ros2ai
 }
 
diff --git a/scripts/verification.sh b/scripts/verification.sh
index ab20177..e653765 100755
--- a/scripts/verification.sh
+++ b/scripts/verification.sh
@@ -29,7 +29,7 @@ command_list=(
     "ros2 ai query -h"
     "ros2 ai query \"say hello\""
     "ros2 ai query \"say hello\" -nv"
-    "ros2 ai query \"say hello\" -m gpt-3.5-turbo -u https://api.openai.com/v1 -t 100"
+    "ros2 ai query \"say hello\" -m gpt-4 -u https://api.openai.com/v1 -t 100"
     "ros2 ai exec \"give me all topics\""
     "ros2 ai exec \"give me all topics\" --dry-run"
     "ros2 ai exec \"give me all topics\" -d"
@@ -40,6 +40,7 @@ command_list=(
 ########################
 
 function exit_trap() {
+    # shellcheck disable=SC2317  # Don't warn about unreachable commands in this function
     if [ $? != 0 ]; then
         echo "Command [$BASH_COMMAND] is failed"
         exit 1
@@ -49,10 +50,8 @@ function exit_trap() {
 function check_user_setting () {
     trap exit_trap ERR
     echo "[${FUNCNAME[0]}]: checking user setting and configuration."
-    # check if API key is set
     if [ -z "$OPENAI_API_KEY" ]; then
-        echo "OPENAI_API_KEY is not set."
-        exit 1
+        echo "OPENAI_API_KEY is not set, if accessing OpenAI it will fail to call API."
     fi
     # check if ros2 envirnoment setting (trap function can catch the error)
     ros2