diff --git a/.gitignore b/.gitignore
index 2d408f3..8e18f6a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,6 +30,7 @@ ENV/
 .pytest_cache/
 .ruff_cache/
 .coverage
+.mypy_cache/
 
 # macOS specific files
 .DS_Store
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 7b884c1..64dae75 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -25,3 +25,8 @@ repos:
        id: detect-private-key
        id: end-of-file-fixer
        id: trailing-whitespace
+
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: v1.3.0
+    hooks:
+    -   id: mypy
diff --git a/gpt_engineer/__init__.py b/gpt_engineer/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/requirements.txt b/requirements.txt
index f3d00e3..1b829e1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,4 +3,5 @@ openai==0.27.8
 pre-commit==3.3.3
 ruff==0.0.272
 typer==0.9.0
-pytest==7.3.1
\ No newline at end of file
+pytest==7.3.1
+mypy==1.3.0
\ No newline at end of file
diff --git a/scripts/benchmark.py b/scripts/benchmark.py
index a909c95..7efa686 100644
--- a/scripts/benchmark.py
+++ b/scripts/benchmark.py
@@ -6,6 +6,7 @@ import subprocess
 
 from itertools import islice
 from pathlib import Path
+from typing import Iterable
 
 from typer import run
 
@@ -15,7 +16,7 @@ def main(
 ):
     path = Path("benchmark")
 
-    folders = path.iterdir()
+    folders: Iterable[Path] = path.iterdir()
 
     if n_benchmarks:
         folders = islice(folders, n_benchmarks)