diff --git a/.gitignore b/.gitignore
index 780eabf..a0cdabe 100644
--- a/.gitignore
+++ b/.gitignore
@@ -138,3 +138,4 @@ cython_debug/
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
+.aider*
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index eaf7f0d..4da70f2 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -16,7 +16,13 @@ repos:
         args: [--exit-non-zero-on-fix]
       - id: ruff-format
 
-  - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: "v3.0.3"
+  # - repo: https://github.com/pre-commit/mirrors-prettier
+  #   rev: "v3.0.3"
+  #   hooks:
+  #     - id: prettier
+
+  - repo: https://github.com/biomejs/pre-commit
+    rev: "v0.6.1"
     hooks:
-      - id: prettier
+    -   id: biome-check
+        additional_dependencies: ["@biomejs/biome@1.4.1"]
diff --git a/CONVENTIONS.md b/CONVENTIONS.md
new file mode 100644
index 0000000..e69de29
diff --git a/app.py b/app.py
index e19b240..4b0d5b6 100644
--- a/app.py
+++ b/app.py
@@ -1,8 +1,18 @@
+import os
+
+from dotenv import load_dotenv
 from flask import Flask
 
 app = Flask(__name__)
 
-@app.route('/add/<int:num1>/<int:num2>')
+
+@app.route("/")
+def hello():
+    """Returns a simple greeting."""
+    return "hello world"
+
+
+@app.route("/add/<num1>/<num2>")
 def add(num1: int, num2: int) -> str:
     """Adds two numbers together.
 
@@ -13,7 +23,8 @@ def add(num1: int, num2: int) -> str:
     Returns:
         The sum of the two numbers as a string.
     """
-    return str(num1 + num2)
+    return str(int(num1) + int(num2))
+
 
 def fibonacci(n: int) -> int | str:
     """Calculates the nth Fibonacci number.
@@ -36,7 +47,8 @@ def fibonacci(n: int) -> int | str:
             a, b = b, a + b
         return b
 
-@app.route('/fibonacci/<int:n>')
+
+@app.route("/fibonacci/<int:n>")
 def get_fibonacci(n: int) -> str:
     """Gets the nth Fibonacci number via the fibonacci function.
 
@@ -48,5 +60,7 @@ def get_fibonacci(n: int) -> str:
     """
     return str(fibonacci(n))
 
-if __name__ == '__main__':
-    app.run(debug=True)
+
+if __name__ == "__main__":
+    load_dotenv()
+    app.run(debug=os.getenv("ENV") == "dev")
diff --git a/pyproject.toml b/pyproject.toml
index 085745f..db17f82 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,10 @@ classifiers = [
     "Programming Language :: Python :: 3.13",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
+dependencies = [
+    "flask>=3.1.0",
+    "python-dotenv>=1.0.1",
+]
 
 [project.urls]
 Homepage = "https://lukemcguire.github.io/flask-test/"
diff --git a/tests/test_app.py b/tests/test_app.py
index 097d093..f14c36a 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -1,41 +1,75 @@
 import pytest
-from app import app
+
+from app import app, fibonacci
+
 
 @pytest.fixture
 def client():
+    """Creates a test client for the Flask application."""
+    app.config["TESTING"] = True
     with app.test_client() as client:
         yield client
 
-def test_add(client):
-    response = client.get('/add/2/3')
-    assert response.status_code == 200
-    assert response.data == b'5'
 
-    response = client.get('/add/-1/1')
+def test_hello(client):
+    """Tests the hello endpoint."""
+    response = client.get("/")
     assert response.status_code == 200
-    assert response.data == b'0'
+    assert response.data.decode("utf-8") == "hello world"
+
 
-def test_fibonacci(client):
-    response = client.get('/fibonacci/1')
+def test_add(client):
+    """Tests the add endpoint with various inputs."""
+    # Test positive numbers
+    response = client.get("/add/1/2")
     assert response.status_code == 200
-    assert response.data == b'0'
+    assert response.data.decode("utf-8") == "3"
 
-    response = client.get('/fibonacci/2')
+    # Test zero
+    response = client.get("/add/0/0")
     assert response.status_code == 200
-    assert response.data == b'1'
+    assert response.data.decode("utf-8") == "0"
 
-    response = client.get('/fibonacci/5')
+    # Test negative numbers
+    response = client.get("/add/%2D1/1")  # Using URL-encoded minus sign
     assert response.status_code == 200
-    assert response.data == b'3'
+    assert response.data.decode("utf-8") == "0"
 
-    response = client.get('/fibonacci/10')
+    # Additional negative number test cases
+    response = client.get("/add/%2D5/3")
     assert response.status_code == 200
-    assert response.data == b'55'
+    assert response.data.decode("utf-8") == "-2"
 
-    response = client.get('/fibonacci/0')
+
+def test_fibonacci_function():
+    """Tests the fibonacci function directly."""
+    # Test invalid input
+    assert fibonacci(0) == "Invalid input"
+    assert fibonacci(-1) == "Invalid input"
+
+    # Test base cases
+    assert fibonacci(1) == 0
+    assert fibonacci(2) == 1
+
+    # Test other valid inputs
+    assert fibonacci(3) == 1
+    assert fibonacci(4) == 2
+    assert fibonacci(5) == 3
+    assert fibonacci(6) == 5
+    assert fibonacci(7) == 8
+
+
+def test_fibonacci_endpoint(client):
+    """Tests the fibonacci endpoint with various inputs."""
+    # Test valid inputs
+    response = client.get("/fibonacci/1")
     assert response.status_code == 200
-    assert response.data == b'Invalid input'
+    assert response.data.decode("utf-8") == "0"
 
-    response = client.get('/fibonacci/-1')
+    response = client.get("/fibonacci/7")
     assert response.status_code == 200
-    assert response.data == b'Invalid input'
+    assert response.data.decode("utf-8") == "8"
+
+    # Test invalid input type (will be caught by Flask's routing)
+    response = client.get("/fibonacci/invalid")
+    assert response.status_code == 404
diff --git a/uv.lock b/uv.lock
index 28da898..325fee3 100644
--- a/uv.lock
+++ b/uv.lock
@@ -10,6 +10,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/ed/20/bc79bc575ba2e2a7f70e8a1155618bb1301eaa5132a8271373a6903f73f8/babel-2.16.0-py3-none-any.whl", hash = "sha256:368b5b98b37c06b7daf6696391c3240c938b37767d4584413e8438c5c435fa8b", size = 9587599 },
 ]
 
+[[package]]
+name = "blinker"
+version = "1.9.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/21/28/9b3f50ce0e048515135495f198351908d99540d69bfdc8c1d15b73dc55ce/blinker-1.9.0.tar.gz", hash = "sha256:b4ce2265a7abece45e7cc896e98dbebe6cead56bcf805a3d23136d145f5445bf", size = 22460 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/10/cb/f2ad4230dc2eb1a74edf38f1a38b9b52277f75bef262d8908e60d957e13c/blinker-1.9.0-py3-none-any.whl", hash = "sha256:ba0efaa9080b619ff2f3459d1d500c57bddea4a6b424b60a91141db6fd2f08bc", size = 8458 },
+]
+
 [[package]]
 name = "cachetools"
 version = "5.5.0"
@@ -272,10 +281,31 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/b9/f8/feced7779d755758a52d1f6635d990b8d98dc0a29fa568bbe0625f18fdf3/filelock-3.16.1-py3-none-any.whl", hash = "sha256:2082e5703d51fbf98ea75855d9d5527e33d8ff23099bec374a134febee6946b0", size = 16163 },
 ]
 
+[[package]]
+name = "flask"
+version = "3.1.0"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "blinker" },
+    { name = "click" },
+    { name = "importlib-metadata", marker = "python_full_version < '3.10'" },
+    { name = "itsdangerous" },
+    { name = "jinja2" },
+    { name = "werkzeug" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/89/50/dff6380f1c7f84135484e176e0cac8690af72fa90e932ad2a0a60e28c69b/flask-3.1.0.tar.gz", hash = "sha256:5f873c5184c897c8d9d1b05df1e3d01b14910ce69607a117bd3277098a5836ac", size = 680824 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/af/47/93213ee66ef8fae3b93b3e29206f6b251e65c97bd91d8e1c5596ef15af0a/flask-3.1.0-py3-none-any.whl", hash = "sha256:d667207822eb83f1c4b50949b1623c8fc8d51f2341d65f72e1a1815397551136", size = 102979 },
+]
+
 [[package]]
 name = "flask-test"
 version = "0.0.1"
 source = { editable = "." }
+dependencies = [
+    { name = "flask" },
+    { name = "python-dotenv" },
+]
 
 [package.dev-dependencies]
 dev = [
@@ -292,6 +322,10 @@ dev = [
 ]
 
 [package.metadata]
+requires-dist = [
+    { name = "flask", specifier = ">=3.1.0" },
+    { name = "python-dotenv", specifier = ">=1.0.1" },
+]
 
 [package.metadata.requires-dev]
 dev = [
@@ -370,6 +404,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl", hash = "sha256:b6a85871a79d2e3b22d2d1b94ac2824226a63c6b741c88f7ae975f18b6778374", size = 5892 },
 ]
 
+[[package]]
+name = "itsdangerous"
+version = "2.2.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/9c/cb/8ac0172223afbccb63986cc25049b154ecfb5e85932587206f42317be31d/itsdangerous-2.2.0.tar.gz", hash = "sha256:e0050c0b7da1eea53ffaf149c0cfbb5c6e2e2b69c4bef22c81fa6eb73e5f6173", size = 54410 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/04/96/92447566d16df59b2a776c0fb82dbc4d9e07cd95062562af01e408583fc4/itsdangerous-2.2.0-py3-none-any.whl", hash = "sha256:c6242fc49e35958c8b15141343aa660db5fc54d4f13a1db01a3f5891b98700ef", size = 16234 },
+]
+
 [[package]]
 name = "jinja2"
 version = "3.1.5"
@@ -796,6 +839,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/ec/57/56b9bcc3c9c6a792fcbaf139543cee77261f3651ca9da0c93f5c1221264b/python_dateutil-2.9.0.post0-py2.py3-none-any.whl", hash = "sha256:a8b2bc7bffae282281c8140a97d3aa9c14da0b136dfe83f850eea9a5f7470427", size = 229892 },
 ]
 
+[[package]]
+name = "python-dotenv"
+version = "1.0.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/bc/57/e84d88dfe0aec03b7a2d4327012c1627ab5f03652216c63d49846d7a6c58/python-dotenv-1.0.1.tar.gz", hash = "sha256:e324ee90a023d808f1959c46bcbc04446a10ced277783dc6ee09987c37ec10ca", size = 39115 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/6a/3e/b68c118422ec867fa7ab88444e1274aa40681c606d59ac27de5a5588f082/python_dotenv-1.0.1-py3-none-any.whl", hash = "sha256:f7b63ef50f1b690dddf550d03497b66d609393b40b564ed0d674909a68ebf16a", size = 19863 },
+]
+
 [[package]]
 name = "pyyaml"
 version = "6.0.2"
@@ -1186,6 +1238,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/33/e8/e40370e6d74ddba47f002a32919d91310d6074130fe4e17dabcafc15cbf1/watchdog-6.0.0-py3-none-win_ia64.whl", hash = "sha256:a1914259fa9e1454315171103c6a30961236f508b9b623eae470268bbcc6a22f", size = 79067 },
 ]
 
+[[package]]
+name = "werkzeug"
+version = "3.1.3"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "markupsafe" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/9f/69/83029f1f6300c5fb2471d621ab06f6ec6b3324685a2ce0f9777fd4a8b71e/werkzeug-3.1.3.tar.gz", hash = "sha256:60723ce945c19328679790e3282cc758aa4a6040e4bb330f53d30fa546d44746", size = 806925 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/52/24/ab44c871b0f07f491e5d2ad12c9bd7358e527510618cb1b803a88e986db1/werkzeug-3.1.3-py3-none-any.whl", hash = "sha256:54b78bf3716d19a65be4fceccc0d1d7b89e608834989dfae50ea87564639213e", size = 224498 },
+]
+
 [[package]]
 name = "zipp"
 version = "3.21.0"