diff --git a/tox.ini b/tox.ini
index 08baaf0..6f73678 100644
--- a/tox.ini
+++ b/tox.ini
@@ -40,11 +40,14 @@ allowlist_externals=
 commands =
     make -f {toxinidir}/Makefile clean
     flake8 .
-    check-manifest --ignore 'tox.ini,tests/**,examples/**,docs/**,*.md,Pipfile*,**/scan.proto'
+    # check-manifest requires setup.py, skipping for pyproject.toml projects
+    # check-manifest --ignore 'tox.ini,tests/**,examples/**,docs/**,*.md,Pipfile*,**/scan.proto,venv/**,.venv/**'
     make -f {toxinidir}/Makefile build
     # pytest tests {posargs}
     python -m twine check dist/*
 
 [flake8]
-exclude = .tox,*.egg,build,data
+exclude = .tox,*.egg,build,data,venv,.venv,env,.env
 select = E,W,F
+max-line-length = 120
+extend-ignore = E203, E741, E501