| `backtrace` | The setting for [`RUST_BACKTRACE`][backtrace] | string | |
| `extra-args` | Extra arguments to pass to the planner (prefer using structured `with:` arguments unless using a custom [planner]!) | string | |
| `extra-conf` | Extra configuration lines for `/etc/nix/nix.conf` (includes `access-tokens` with `secrets.GITHUB_TOKEN` automatically if `github-token` is set) | string | |
| `flakehub` | Log in to FlakeHub to pull private flakes using the GitHub Actions [JSON Web Token](https://jwt.io) (JWT), which is bound to the `api.flakehub.com` audience. | Boolean | `false` |
| `github-token` | A [GitHub token] for making authenticated requests (which have a higher rate-limit quota than unauthenticated requests) | string | `${{ github.token }}` |
| `init` | The init system to configure (requires `planner: linux-multi`) | enum (`none` or `systemd`) | |
| `local-root` | A local `nix-installer` binary root. Overrides the `nix-installer-url` setting (a `nix-installer.sh` should exist, binaries should be named `nix-installer-$ARCH`, eg. `nix-installer-x86_64-linux`). | Boolean | `false` |
| `log-directives` | A list of [tracing directives], comma separated with `-`s replaced with `_` (eg. `nix_installer=trace`) | string | |
| `logger` | The logger to use during installation | enum (`pretty`, `json`, `full`, `compact`) | |
| `mac-case-sensitive` | Use a case-sensitive volume (`planner: macos` only) | Boolean | `false` |
| `mac-encrypt` | Force encryption on the volume (`planner: macos` only) | Boolean | `false` |
| `mac-root-disk` | The root disk of the target (`planner: macos` only) | string | |
| `mac-volume-label` | The label for the created [APFS] volume (`planner: macos` only) | string | |
| `modify-profile` | Modify the user [profile] to automatically load Nix | Boolean | `false` |
| `nix-build-group-id` | The Nix build group GID | integer | |
| `nix-build-group-name` | The Nix build group name | string | |
| `nix-build-user-base` | The Nix build user base UID (ascending) | integer | |
| `nix-build-user-count` | The number of build users to create | integer | 32 |
| `nix-build-user-prefix` | The Nix build user prefix (user numbers will be postfixed) | string | |
| `nix-installer-branch` | The branch of `nix-installer` to use (conflicts with the `nix-installer-tag`, `nix-installer-revision`, and `nix-installer-branch`) | string | |
| `nix-installer-pr` | The pull request of `nix-installer` to use (conflicts with `nix-installer-tag`, `nix-installer-revision`, and `nix-installer-branch`) | integer | |
| `nix-installer-revision` | The revision of `nix-installer` to use (conflicts with `nix-installer-tag`, `nix-installer-branch`, and `nix-installer-pr`) | string | |
| `nix-installer-tag` | The tag of `nix-installer` to use (conflicts with `nix-installer-revision`, `nix-installer-branch`, `nix-installer-pr`) | string | |
| `nix-installer-url` | A URL pointing to a `nix-installer.sh` script | URL | `https://install.determinate.systems/nix` |
| `diagnostic-endpoint` | Diagnostic endpoint url where the installer sends install [diagnostic reports](https://github.com/DeterminateSystems/nix-installer#diagnostics) to, to disable set this to an empty string | string | `https://install.determinate.systems/nix/diagnostic` |
| `proxy` | The proxy to use (if any), valid proxy bases are `https://$URL`, `http://$URL` and `socks5://$URL` | string | |
| `ssl-cert-file` | An SSL cert to use (if any), used for fetching Nix and sets `NIX_SSL_CERT_FILE` for Nix | string | |