> ## Documentation Index
> Fetch the complete documentation index at: https://docs.solved.gg/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment variables

> RUSTY_* and cargo-compatible variables rusty sets or honors.

## Primary

| Variable                    | Default / notes                                                  |
| --------------------------- | ---------------------------------------------------------------- |
| `RUSTY_HOME`                | Data root; default `~/.rusty`                                    |
| `RUSTY_PROJECT_ROOT`        | Set during build to the workspace root                           |
| `RUSTY_TOOLCHAIN`           | Override active toolchain name                                   |
| `RUSTY_JOBS`                | Parallel jobs for build/test (also `-j`)                         |
| `RUSTY_BUILD_CACHE`         | Set to `0` to disable native build unit CAS cache                |
| `RUSTY_TEST_CACHE`          | Set to `0` to disable test binary cache                          |
| `RUSTY_NO_SCRIPTS`          | Set to `1` to skip lifecycle script hooks                        |
| `RUSTY_INSTALL_ALLOW_CARGO` | Set to `1` to allow `cargo install` after prebuilt + native miss |
| `RUSTY_INSTALL_NO_CARGO`    | Force no cargo install path even if allow is set                 |
| `RUSTY_AUTH_CLIENT_ID`      | Clerk OAuth client for `rusty auth`                              |
| `RUSTY_AUTH_ISSUER`         | Clerk / OIDC issuer for `rusty auth`                             |

## Cargo-compatible (often set by rusty)

| Variable           | Role under rusty                                                                                       |
| ------------------ | ------------------------------------------------------------------------------------------------------ |
| `CARGO_HOME`       | Points at `$RUSTY_HOME/cargo-home` during prepared builds/interop                                      |
| `CARGO_TARGET_DIR` | `<workspace>/.rusty/target`                                                                            |
| `CARGO_PROFILE`    | `debug` or `release`                                                                                   |
| `RUSTC_WRAPPER`    | `$RUSTY_HOME/bin/rusty-wrapper` for layer caching                                                      |
| `CARGO`            | May point at toolchain cargo sibling of rustc for build-script env (not a substitute for the resolver) |

## Project paths

| Path                     | Purpose                                          |
| ------------------------ | ------------------------------------------------ |
| `$RUSTY_HOME`            | Toolchains, store, auth, bin shims               |
| `$RUSTY_HOME/bin`        | Proxies after `env use`                          |
| `$RUSTY_HOME/cargo-home` | Managed cargo-home layout                        |
| `$RUSTY_HOME/auth.db`    | Product auth session                             |
| `<root>/.rusty/`         | Format marker, target, layer index, graph caches |
| `<root>/.rusty/format`   | `rusty` or `cargo`                               |
| `<root>/.rusty/target`   | Build outputs                                    |

## Interop notes

* Default toolchain install does **not** include cargo.
* Interop verbs without cargo fail with exit **127**.
* Doc/bench prep may append `--offline` when the offline prep path ran.


## Related topics

- [Toolchains](/rusty/0.0.1-dev/concepts/toolchains.md)
- [Store and cache](/rusty/0.0.1-dev/concepts/store-and-cache.md)
- [Introduction](/pyppi/0.0.1-dev/index.md)
- [How rusty works](/rusty/0.0.1-dev/concepts/overview.md)
- [Install](/rusty/0.0.1-dev/install.md)