how to invalidate toxenv

I have some tox project that processes some protobuf in the install-deps phase and outputs some *pb.py codecs (custom script executed as install_command option in the config). When I'm updating my workspace (and the protobuf files are updated), i would like to somehow mark the toxenv as invalid - so that it would get recreated without the need of passing -r, --recreate flags to some later tox call. I could add such action the the script that does the env update. Any idea on how to do it?
i'm using some older tox - 3.14

turns out its described quite verbosly in the doc:
https://tox.wiki/en/3.14.6/example/general.html?highlight=recreate#dependency-changes-and-tracking

> Here’s what traits we track at the moment for each steps:
> * virtual environment trait is tied to the python path the basepython resolves too (if this config changes, the virtual environment will be recreated),
> * deps sections changes (meaning any string-level change for the entries, note requirement file content changes are not tracked),
> * library dependencies are tracked at extras level (because there’s no Python API to enquire about the actual dependencies in a non-tool specific way, e.g. setuptools has one way, flit something else, and poetry another).

Also from what i looked into tox code, here are the attributes that are checked
https://tox.wiki/en/3.14.6/_modules/tox/venv.html?highlight=matches_with_reason

• base_resolved_python_sha256
• base_resolved_python_path
• tox_version
• sitepackages
• usedevelop
• alwayscopy

Apart from that, the first and most obvious way is to simply remove the <toxworkdir> dir on the env update. Other possibility can be to remove/rename the <toxenvdir>/.tox-config1 file.