Environment variables

Variables meow reads

Set these to change meow’s behavior.

Variable	Effect
`MEOW_HOME`	Relocate the global `~/.meow` tree (cache, bin, global installs). Child runtimes inherit it.
`MEOW_TRUST_ALL`	`=1` grants full host access on every run — equivalent to `--trust` (clock, random, env, and the fs/network sandbox off). Replaces `MEOW_DANGEROUSLY_DISABLE_SECURITY`, which still works as an alias.
`MEOW_SANDBOX`	`=1` forces the fs/network sandbox on for every `meow run` — equivalent to `--sandbox`. An explicit `--trust` / `MEOW_TRUST_ALL` overrides it.
`MEOW_NO_SHIM`	`=1` makes the `node`/`npm`/… shims exec the real system binary instead of re-entering meow.
`MEOW_METADATA_MAX_AGE_SECS`	Freshness window (seconds) for cached registry metadata. Default `300`. `0` always revalidates; a large value stays effectively offline.
`MEOW_INSTALL_TRACE`	When set, prints per-phase install timings (resolve, lockfile, materialize) to stderr.
`MEOW_TSC`	Path to a specific `tsc` binary for `meow types` (the contributor type-gen command).
`NODE_OPTIONS`	meow reads `--max-old-space-size=<MiB>` from it, for drop-in compatibility.

The UI engine resolves its rendering from standard terminal signals — so meow plays well with CI and pipelines automatically.

Variable	Effect
`NO_COLOR`	Disable all color.
`FORCE_COLOR`	Force color depth (`0` off, `1`/`2`/`3` for 16/256/truecolor).
`CLICOLOR_FORCE`	Non-`0` forces color even when not a TTY.
`CI`	When set, meow assumes a non-interactive environment (no animations).
`TERM`, `COLORTERM`, `TERM_PROGRAM`	Detect color/Unicode capabilities.
`COLUMNS`	Width hint for layout.
`LANG`, `LC_ALL`, `LC_CTYPE`	UTF-8 detection for glyphs.

In a pipe or CI, meow drops spinners, animations, and ANSI automatically — output stays clean and greppable. You rarely need to set these by hand.

When meow runs your code, it injects a few variables so Node-style tooling finds its bearings:

Variable	Value
`MEOW_NODE_SHIM`	`1` while running through meow, so re-entrant `node` calls route correctly.
`MEOW_EXEC_PATH`	Path to the meow binary.
`MEOW_NODE_PLATFORM` / `MEOW_NODE_ARCH`	Normalized platform/arch (`darwin`/`win32`/`linux`, `arm64`/`x64`).
`NODE` / `npm_node_execpath`	Path to the shimmed `node`, so tools spawn “the current Node” back into meow.
`INIT_CWD`	The directory a `package.json` script was invoked from.
`npm_lifecycle_event` / `npm_lifecycle_script`	The script name and body, npm-style.
`npm_package_json`	Absolute path to the project `package.json`.

For deterministic runs, meow also pins TZ=UTC and a fixed locale before creating the isolate — see Determinism.

process.env exists only in node-compat (there is no process global in strict-web at all). What it contains depends on your grant:

process.env is populated from the full host environment, like Node.

meow run app.ts          # process.env has everything

Narrow it for a more reproducible run:

meow run app.ts --allow-env=API_BASE,LOG_LEVEL

The host environment is invisible — there is no process global, and the hermetic env seam returns nothing. Grant access explicitly:

meow run app.ts --allow-env=API_BASE      # only API_BASE resolves
meow run app.ts --allow-env                # everything visible

The full grant model for env, clock, randomness, and the fs/network sandbox.