CI’s pytest dependency image is built from the published Flox toolchain image. GitHub Actions publishes both arm64 and amd64 variants with immutable tags in this form:
The integration workflow selects the arm64 tag because it runs on ubuntu-24.04-arm. Other consumers must select the tag matching their runner architecture; tests must not use latest.
The image contains the locked Python environment plus the Flox runtime tools used by CI (uv, git, gh, and time). The runtime contract is UID 1000, with /opt/venv and /home/runner/.cache/uv writable by that user. Publication validates that the image’s uv version matches the version recorded in flox/toolchain/.flox/env/manifest.lock.
Image publication is a GitHub Actions responsibility. Local setup and review workflows consume an already-published immutable image and do not build or push the pytest image. Last modified on August 4, 2026
