diff --git a/src/review_bot/open_ai_interface.py b/src/review_bot/open_ai_interface.py
index 0682abc9..45a067f3 100644
--- a/src/review_bot/open_ai_interface.py
+++ b/src/review_bot/open_ai_interface.py
@@ -15,7 +15,9 @@
 OPEN_AI_MODEL = "gpt-4"
 
 
-def review_patch(owner, repo, pr, use_src=False, filter_filename=None):
+def review_patch(
+    owner, repo, pr, use_src=False, filter_filename=None, gh_access_token=None
+):
     """Review a patch in a pull request and generate suggestions for improvement.
 
     Parameters
@@ -31,6 +33,9 @@ def review_patch(owner, repo, pr, use_src=False, filter_filename=None):
         not for large ones.
     filter_filename : str, optional
         If set, filters out all but the file matching this string.
+    gh_access_token : str, optional
+        GitHub token needed to communicate with the repository. By default, ``None``,
+        which means it will try to read an existing env variable named ``GITHUB_TOKEN``.
 
     Returns
     -------
@@ -38,7 +43,9 @@ def review_patch(owner, repo, pr, use_src=False, filter_filename=None):
         A dictionary containing suggestions for the reviewed patch.
     """
     # Fetch changed files and contents
-    changed_files = get_changed_files_and_contents(owner, repo, pr)
+    changed_files = get_changed_files_and_contents(
+        owner, repo, pr, gh_access_token=gh_access_token
+    )
 
     # assemble suggestions
     suggestions = []
diff --git a/tests/test_gh_interface.py b/tests/test_gh_interface.py
index e373dc4b..0a4acf77 100644
--- a/tests/test_gh_interface.py
+++ b/tests/test_gh_interface.py
@@ -5,6 +5,7 @@
 > Make this a pytest compatible test, and make it just a function test, do not make it a class.
 
 """
+import os
 
 import pytest
 
@@ -28,6 +29,20 @@ def test_get_changed_files_and_contents():
     assert "file_text" in files[0]
 
 
+def test_get_changed_files_and_contents_with_input_token():
+    pull_number = 4
+
+    access_token = os.environ.get("GITHUB_TOKEN")
+    files = get_changed_files_and_contents(OWNER, REPO, pull_number, access_token)
+
+    assert isinstance(files, list)
+    assert len(files) > 0
+    assert isinstance(files[0], dict)
+    assert "filename" in files[0]
+    assert "status" in files[0]
+    assert "file_text" in files[0]
+
+
 def test_get_changed_files_and_contents_raises_runtime_error():
     pull_number = 999999  # this is an issue