# macstate
macOS system signals as JSON — a CLI and a Rust library.
Surfaces signals that aren't directly readable from the shell:
- **Network** — Low Data Mode (`constrained`), expensive link (cellular/hotspot), interface kind
- **Power** — AC vs battery, battery percent, Low Power Mode, Energy Mode (automatic/low/high)
`low_power_mode` reports the *currently active* state (via
`NSProcessInfo.isLowPowerModeEnabled`); `energy_mode` reports the
*configured preference* for the current power source (AC or Battery)
read from IOKit's active PM preferences — the same source `pmset` uses.
macOS only.
## Install
From crates.io (requires a Rust toolchain):
```sh
cargo install macstate
```
Prebuilt binary via [`cargo-binstall`](https://github.com/cargo-bins/cargo-binstall) (no toolchain needed):
```sh
cargo binstall macstate
```
Or pin to the bleeding edge from git:
```sh
cargo install --git https://github.com/DaveDev42/macstate macstate
```
Update any of the above with `--force`.
## Usage
Default: print everything as JSON and exit.
```sh
$ macstate
{
"network": {
"constrained": false,
"expensive": false,
"interface": "wifi"
},
"power": {
"source": "ac",
"battery_percent": 87,
"low_power_mode": false,
"energy_mode": "automatic"
}
}
```
Subsets:
```sh
macstate --network
macstate --power
```
Single value at a dotted path:
```sh
$ macstate -q network.constrained
false
$ macstate -q power.battery_percent
87
```
Shell guard via exit code (true → 0, false → 1):
```sh
macstate --check network.constrained && echo "low data mode on"
```
JSON Schema for the output (useful for AI agents and downstream tools):
```sh
macstate --schema # print to stdout
macstate --schema > schema.json
```
The schema is generated from the Rust types at runtime via
[`schemars`](https://crates.io/crates/schemars), so it always matches
what the CLI actually emits.
## Library
```toml
[dependencies]
macstate-core = "0.0"
```
```rust
let state = macstate_core::State::collect();
println!("{}", state.power.battery_percent.unwrap_or(0));
```
## License
BSD 3-Clause. See [LICENSE](LICENSE).