# canact
> Probe an LLM and return host policy: max tools, edit format, XML fallback, JSON repair.
canact is a Rust crate plus a `canact` CLI. A host that already has this
URL should read this file, then the linked pages that match the task.
## Install
```bash
cargo install canact --locked --features cli
```
The `canact` binary needs `--features cli`. Default features stay empty so
a library pin does not pull clap. GitHub Releases also ship archives and
a shell installer. Extra taps (`brew install canact/tap/canact`, Scoop
`canact/scoop-bucket`) update after those zips exist.
## Docs
- [README](https://github.com/canact/canact/blob/main/README.md): install, `canact probe`, library sketch
- [examples](https://github.com/canact/canact/tree/main/examples): no-network host-policy JSON and Aider/Cline overlays
- [SECURITY](https://github.com/canact/canact/blob/main/SECURITY.md): private vulnerability reports
## Host contract
- Library entry: `ProbeRunner::new` (paid) or `ProbeRunner::new_throttled` / `.cheap()` (free or local). Feature `runtime`. Call `run()` or `run_detailed()`. Persist only with `ProbeRun::persist` / `ProbeRunner::persist` when the run is cacheable.
- Disk cache (`probes.json`) is `ProbeCache`: pretty JSON, 30-day TTL, key includes model, provider, effort, and `PROBE_SUITE_VERSION`. That file is not the CLI envelope.
- CLI `canact probe --json` prints a host-policy envelope (`maxTools`, `fromCache`, `cacheable`, `recommendedContextTokens`, per-probe `status`). `fromCache` is a cache hit. `cacheable` is persist-for-30-days.
- `maxTools` follows completed `tool_selection` only: Strong unlimited (`null`), Medium 20, Weak 10. Transient or skipped cores do not collapse overall and do not force JSON repair.
- Auth, missing model, and connect failures abort the suite. Timeouts and 429/5xx are Transient and must not be stored as a 30-day Weak or Medium card.
## Optional
- [AGENTS.md](https://github.com/canact/canact/blob/main/AGENTS.md): clone-local build and DCO notes
- [CONTRIBUTING.md](https://github.com/canact/canact/blob/main/CONTRIBUTING.md)
- [CHANGELOG](https://github.com/canact/canact/blob/main/CHANGELOG.md)