diff --git a/poetry.lock b/poetry.lock
index 283e80b..2885bbf 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -984,6 +984,27 @@ files = [
     {file = "tomli-2.0.1.tar.gz", hash = "sha256:de526c12914f0c550d15924c62d72abc48d6fe7364aa87328337a31007fe8a4f"},
 ]
 
+[[package]]
+name = "typer"
+version = "0.9.0"
+description = "Typer, build great CLIs. Easy to code. Based on Python type hints."
+optional = false
+python-versions = ">=3.6"
+files = [
+    {file = "typer-0.9.0-py3-none-any.whl", hash = "sha256:5d96d986a21493606a358cae4461bd8cdf83cbf33a5aa950ae629ca3b51467ee"},
+    {file = "typer-0.9.0.tar.gz", hash = "sha256:50922fd79aea2f4751a8e0408ff10d2662bd0c8bbfa84755a699f3bada2978b2"},
+]
+
+[package.dependencies]
+click = ">=7.1.1,<9.0.0"
+typing-extensions = ">=3.7.4.3"
+
+[package.extras]
+all = ["colorama (>=0.4.3,<0.5.0)", "rich (>=10.11.0,<14.0.0)", "shellingham (>=1.3.0,<2.0.0)"]
+dev = ["autoflake (>=1.3.1,<2.0.0)", "flake8 (>=3.8.3,<4.0.0)", "pre-commit (>=2.17.0,<3.0.0)"]
+doc = ["cairosvg (>=2.5.2,<3.0.0)", "mdx-include (>=1.4.1,<2.0.0)", "mkdocs (>=1.1.2,<2.0.0)", "mkdocs-material (>=8.1.4,<9.0.0)", "pillow (>=9.3.0,<10.0.0)"]
+test = ["black (>=22.3.0,<23.0.0)", "coverage (>=6.2,<7.0)", "isort (>=5.0.6,<6.0.0)", "mypy (==0.910)", "pytest (>=4.4.0,<8.0.0)", "pytest-cov (>=2.10.0,<5.0.0)", "pytest-sugar (>=0.9.4,<0.10.0)", "pytest-xdist (>=1.32.0,<4.0.0)", "rich (>=10.11.0,<14.0.0)", "shellingham (>=1.3.0,<2.0.0)"]
+
 [[package]]
 name = "typing-extensions"
 version = "4.8.0"
@@ -1029,4 +1050,4 @@ test = ["covdefaults (>=2.3)", "coverage (>=7.2.7)", "coverage-enable-subprocess
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.10"
-content-hash = "738ec68fb794caaa73108443aa5653fda2bb4bce3953b50dc3a09db492a46e56"
+content-hash = "322c547268317f46591599a02d8b8486c03b3d92b8b0a0f37adf556feb2a578f"
diff --git a/pyproject.toml b/pyproject.toml
index 83460cf..d266f14 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,6 +14,7 @@ pandas = "^2.1.4"
 pyarrow = "^14.0.1"
 scipy = "^1.11.4"
 jinja2 = "^3.1.2"
+typer = "^0.9.0"
 
 [tool.poetry.group.dev.dependencies]
 rich = "^13.6.0"
@@ -28,6 +29,9 @@ enable = true
 vcs = "git"
 style = "semver"
 
+[tool.poetry.scripts]
+deemian = "deemian.deemian:app"
+
 [build-system]
 requires = ["poetry-core>=1.0.0", "poetry-dynamic-versioning>=1.0.0,<2.0.0"]
 build-backend = "poetry_dynamic_versioning.backend"
diff --git a/src/deemian/deemian.py b/src/deemian/deemian.py
index e69de29..0195437 100644
--- a/src/deemian/deemian.py
+++ b/src/deemian/deemian.py
@@ -0,0 +1,32 @@
+import typer
+from rich.console import Console
+
+from deemian.engine.builder import DeemianData
+from deemian.engine.processor import parser, InstructionTransformer
+from deemian.engine.director import director
+
+
+console = Console()
+app = typer.Typer()
+
+
+@app.command(short_help="run deemian script")
+def run(script_name: str):
+    console.print(f"[bold magenta]Running {script_name}[/bold magenta]")
+    with open(script_name) as f:
+        text = f.read()
+
+    command_tree = parser(text)
+    transformer = InstructionTransformer()
+    command_tree = transformer.transform(command_tree)
+
+    deemian_data = DeemianData()
+    director(command_tree, deemian_data)
+
+
+# one command one callback, just a temporary helper command
+# delete this when there are multiple commands
+# https://typer.tiangolo.com/tutorial/commands/one-or-multiple/
+@app.callback()
+def callback():
+    pass
diff --git a/src/deemian/writer/templates/01_detailed_conf_first.txt b/src/deemian/writer/templates/01_detailed_conf_first.txt
index 0c7f63f..e0469f1 100644
--- a/src/deemian/writer/templates/01_detailed_conf_first.txt
+++ b/src/deemian/writer/templates/01_detailed_conf_first.txt
@@ -4,6 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subject_1, subject_2 = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set confs = df.conformation.unique() -%}
 {%- set groupbyconf = df.groupby('conformation') -%}
 
@@ -52,4 +55,5 @@ conf {{ "{}".format(conf).rjust(10) }}
 {% endfor -%}
 {% endif %}
 {% endfor %}
+{% endif %}
 {% endfor %}
diff --git a/src/deemian/writer/templates/02_detailed_type_first.txt b/src/deemian/writer/templates/02_detailed_type_first.txt
index 835a1d7..26ccbd5 100644
--- a/src/deemian/writer/templates/02_detailed_type_first.txt
+++ b/src/deemian/writer/templates/02_detailed_type_first.txt
@@ -4,6 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subject_1, subject_2 = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set unique_interaction = df.interaction_type.unique() %}
 {%- set groupbytype = df.groupby('interaction_type') %}
 
@@ -55,4 +58,5 @@ interaction for "{{ pair_name }}":
 {% endfor -%}
 {% endfor -%}
 {%- endif %}
+{% endif %}
 {% endfor %}
diff --git a/src/deemian/writer/templates/03_clustered_conf_first.txt b/src/deemian/writer/templates/03_clustered_conf_first.txt
index cc17008..81f6c25 100644
--- a/src/deemian/writer/templates/03_clustered_conf_first.txt
+++ b/src/deemian/writer/templates/03_clustered_conf_first.txt
@@ -4,6 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subject_1, subject_2 = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set confs = df.conformation.unique() -%}
 {%- set groupbyconf = df.groupby('conformation') -%}
 
@@ -54,4 +57,5 @@ conf {{ "{}".format(conf).rjust(10) }}
 {% endfor -%}
 {%- endif %}
 {% endfor %}
+{% endif %}
 {% endfor %}
diff --git a/src/deemian/writer/templates/04_clustered_type_first.txt b/src/deemian/writer/templates/04_clustered_type_first.txt
index 8be88d8..359f72c 100644
--- a/src/deemian/writer/templates/04_clustered_type_first.txt
+++ b/src/deemian/writer/templates/04_clustered_type_first.txt
@@ -4,7 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subject_1, subject_2 = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
-
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set unique_interaction = df.interaction_type.unique() %}
 {%- set groupbytype = df.groupby('interaction_type') %}
 {%- if 'electrostatic_cation' in unique_interaction %}
@@ -59,4 +61,5 @@ interaction for "{{ pair_name }}":
 {% endfor -%}
 {% endfor %}
 {%- endif %}
+{% endif %}
 {% endfor %}
diff --git a/src/deemian/writer/templates/05_summarized_conf_first.txt b/src/deemian/writer/templates/05_summarized_conf_first.txt
index fba5523..e546b4f 100644
--- a/src/deemian/writer/templates/05_summarized_conf_first.txt
+++ b/src/deemian/writer/templates/05_summarized_conf_first.txt
@@ -4,6 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subjects = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set confs = df.conformation.unique() -%}
 {%- set groupbyconf = df.groupby('conformation') -%}
 
@@ -63,4 +66,5 @@ conf {{ "{}".format(conf).rjust(10) }}
 {% endfor -%}
 {%- endif %}
 {% endfor %}
+{% endif %}
 {% endfor %}
diff --git a/src/deemian/writer/templates/06_summarized_type_first.txt b/src/deemian/writer/templates/06_summarized_type_first.txt
index 80a6074..3a37686 100644
--- a/src/deemian/writer/templates/06_summarized_type_first.txt
+++ b/src/deemian/writer/templates/06_summarized_type_first.txt
@@ -4,7 +4,9 @@ interaction for "{{ pair_name }}":
 
 {%- set subjects = interacting_subjects[pair_name] -%}
 {%- set df = interaction_data.dataframe -%}
-
+{%- if len(df) == 0 %}
+    No interaction detected
+{%- else -%}
 {%- set unique_interaction = df.interaction_type.unique() %}
 {%- set groupbytype = df.groupby('interaction_type') %}
 {%- if 'electrostatic_cation' in unique_interaction %}
@@ -69,4 +71,5 @@ interaction for "{{ pair_name }}":
 {% endfor -%}
 {% endfor -%}
 {%- endif %}
+{% endif %}
 {% endfor %}
diff --git a/tests/test_deemian.py b/tests/test_deemian.py
index a86713a..e2cafbf 100644
--- a/tests/test_deemian.py
+++ b/tests/test_deemian.py
@@ -1 +1,14 @@
-# from deemian import deemian
+from unittest.mock import patch
+
+from typer.testing import CliRunner
+
+from deemian.deemian import app
+
+
+runner = CliRunner()
+
+
+def test_app():
+    with patch("deemian.deemian.director"):
+        result = runner.invoke(app, ["run", "tests/data/n1-oseltamivir-5nzn.txt"])
+        assert result.exit_code == 0