D109 — Engine never talks to a model; advice files

Decision

The engine never talks to a model. A language model is one possible writer of an advice file (--advice FILE: typed hints, strictly checked, that change only the order of connections, the cost of a layer and where some nets may not go), run by an out-of-process advisor (--advisor CMD: stuck report on stdin, advice on stdout) that is consulted only when the plain route leaves connections open. Advice never contains copper or rule values; unknown keys, wrong types and unknown names are errors

Alternatives

An HTTP/TLS client and API keys inside the C++ engine; a separate orchestrator program; letting a model place copper

Reason

The tree has no HTTP client, and a non-repeatable call inside a run that must be byte-identical breaks N3 and rule 2. The model's answer is frozen in a file, so board + options + seed + advice is repeatable. Two tools for one job would leave the report and hint interface, the real work, in the engine anyway (doc 17 §1–§2)