diff --git a/.librarian/generator-input/noxfile.py b/.librarian/generator-input/noxfile.py
index 16dca84d..7d1fed58 100644
--- a/.librarian/generator-input/noxfile.py
+++ b/.librarian/generator-input/noxfile.py
@@ -116,7 +116,7 @@ def lint(session):
     session.run("flake8", "google", "tests")
 
 
-@nox.session(python="3.13")
+@nox.session(python="3.14")
 def blacken(session):
     """Run black. Format code to uniform standard."""
     session.install(BLACK_VERSION)
diff --git a/noxfile.py b/noxfile.py
index 3331fd35..51d0c48b 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -120,7 +120,7 @@ def lint(session):
     session.run("flake8", "google", "tests")
 
 
-@nox.session(python="3.13")
+@nox.session(python=DEFAULT_PYTHON_VERSION)
 def blacken(session):
     """Run black. Format code to uniform standard."""
     session.install(BLACK_VERSION)