A request naming collections in X-Llmgw-Knowledge has its last question
embedded on the caller's account, the best passages found and added to the
system message, numbered, with an instruction to cite them and to say when
they do not hold the answer; x-llmgw-sources says which were given. Done
before the guardrails judge the request, never served from the answer cache,
and a collection the key may not read is answered as one that does not
exist. Metrics llmgw_kb_retrievals_total and llmgw_kb_retrieval_seconds.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
