Environment variables

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`

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)

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