Architecture

canact is one crate: a library plus an optional canact binary.

src/lib.rs          public types and re-exports
  cache             probes.json (30-day TTL, not the CLI envelope)
  endpoint          provider URL and host-family hints
  types             CapabilityProfile, levels, host-policy fields
  error             Auth / NotFound abort; Transient stays session-local
                    a window rejection keeps the last ladder rung
                    a safety stop is Transient and is not cached
                    a malformed tool call is a completed Weak
  runtime           ProbeClient, ProbeRunner, graders
  adapters/openai   OpenAI-compat, Anthropic, Ollama, xAI
src/bin/canact.rs   CLI, export, and `canact mcp` (feature `cli`)
  export            Aider / Cline overlays

Default features are empty. A library pin uses default-features = false plus runtime. The binary needs --features cli.

The host-policy card is the product: max_tools, edit-format ladder, XML fallback, and JSON repair. Graders live next to the probes they score. Types and CLI goldens are the source of truth.

Tests: cargo test --locked --features runtime --lib. Local gate: make check.