The review fork's entire job is to emit `memory` / `skill_manage` tool calls,
and by default it inherits the parent's live runtime. A provider that IS an
autonomous agent reaches Hermes through a client shim; if that shim cannot
carry Hermes tool calls back, the fork is a guaranteed no-op that still pays
for a full agent spawn — a whole CLI process, sometimes a JVM — on every
review cadence.
A client declares `SUPPORTS_HERMES_TOOL_CALLS = False` and the fork is
skipped with a warning naming the `auxiliary.background_review.{provider,model}`
override that routes the review to a normal model instead. Anything that says
nothing is assumed capable, so ordinary providers are untouched.
The check runs before the thread-scoped silence so the warning is not
swallowed, and only resolves the review runtime once the cheap capability
test has already failed, so the normal path does not resolve it twice.
Alexander Prendota