Development record

2026-09-25 — The layered configuration resolver has one home, `internal/core/layered`, and two file families; every later consumer reads through it rather than opening a file of its own (lane implementer, autonomous run A, on spc-2609180535002478 part 1). Precedence is flag, then repository, then machine, then bundled, and every value comes back with the layer and the origin that supplied it. The families are `layered.Config`, which is `.abcd/config.json` in the checkout the session resolved and `~/.abcd/config.json` on the machine, and `layered.OracleRouting`, which is `.abcd/config/oracle-routing.json` and `~/.abcd/oracle-routing.json`, the files itd-2609170822093401 names. Scalar keys go in `Config` under a namespace: `pace.*` (itd-2609201925079472), `oracle.review` (itd-6), `roles.<role>.runner` (itd-2609201916056194) and `match.threshold` (itd-2609212137116617). The per-agent routing table keeps its own file, as its intent names, and no new file family is added without an entry here. Loudness: an absent file is an absent layer; a present file that is malformed, symlinked, carries a key twice, trails content, declares the wrong `schema_version`, or (machine layer) is not the caller's own owner-only-writable file is an error naming it; a consumer claims its namespace and every key in it (`Stack.Claim`, with `*` for an open segment such as the role name), and an unknown key under a claimed namespace is refused. Because ahoy writes `oracle.backend` into the shared file, whoever claims `oracle` lists `backend` too. A winning value that does not decode or fails its check is refused, and nothing falls through to a lower layer or to the default.