Here’s a little script I created to check free-threading support in dependencies. It reads pyproject.toml and uv.lock and checks each package’s PyPI metadata for either the free-threading trove classifiers or free-threading compatible wheels. You can specify overrides in [tool.free-threading-check.overrides] in your pyproject.toml.
Just run uv run check-freethreading-support.py in your project directory.