diff --git a/pyproject.toml b/pyproject.toml
index cb6a203..0c30ae7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,7 @@ Issues = "https://github.com/nonannet/copapy/issues"
 requires = ["setuptools>=61.0", "wheel"]
 build-backend = "setuptools.build_meta"
 
-tool.setuptools]
+[tool.setuptools]
 license-files = []
 
 [tool.setuptools.packages.find]