diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..8e955b1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+__pycache__/*
+*.swp
+*.swo
diff --git a/int_to_text.py b/numberwords.py
similarity index 99%
rename from int_to_text.py
rename to numberwords.py
index 780d701..394f7ea 100644
--- a/int_to_text.py
+++ b/numberwords.py
@@ -52,7 +52,7 @@ def int_under_100_to_text(number):
             return int_under_10_to_text(ones) + "teen"
         elif number == 15:
             return "fifteen"
-        elif number == 13:
+        elif number == 14:
             return "fourteen"
         elif number == 13:
             return "thirteen"
diff --git a/cli.py b/nw.py
similarity index 65%
rename from cli.py
rename to nw.py
index 5d97288..f331357 100644
--- a/cli.py
+++ b/nw.py
@@ -3,10 +3,11 @@
 # Implements a simple number-to-text command-line interface.
 
 from argparse import ArgumentParser
-from int_to_text import int_under_1000000_to_text
+from numberwords import int_under_1000000_to_text
 
-parser = ArgumentParser()
+parser = ArgumentParser("Print out a number as it is spoken in English.")
 parser.add_argument("number", type=int)
 args = parser.parse_args()
 text = int_under_1000000_to_text(args.number)
 print(text)
+
diff --git a/poetry.lock b/poetry.lock
new file mode 100644
index 0000000..ddb1526
--- /dev/null
+++ b/poetry.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Poetry 1.5.1 and should not be changed by hand.
+package = []
+
+[metadata]
+lock-version = "2.0"
+python-versions = "^3.10"
+content-hash = "53f2eabc9c26446fbcc00d348c47878e118afc2054778c3c803a0a8028af27d9"
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..3151661
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,16 @@
+[tool.poetry]
+name = "problemset-numberwords"
+version = "0.1.0"
+description = ""
+authors = ["Chris Proctor <chris@chrisproctor.net>"]
+readme = "README.md"
+
+[tool.poetry.dependencies]
+python = "^3.10"
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"
+
+[tool.poetry.scripts]
+numwords = "cli:cli"