# docs/ai — index

Subsystem truth, split out so a session pays only for what its task touches. `ai.md` routes here;
`AGENTS.md` carries the invariants that hold across every subsystem.

| File | Covers | Read when |
|---|---|---|
| [`environment.md`](environment.md) | Hosts, ports, paths, build/run/test commands, test map | building, running, adding a test |
| [`decisions.md`](decisions.md) | Retired paths with cause of death; the permanent out-of-scope list | about to re-open a settled decision |
| <topic>.md | <subsystem> | <trigger> |