The RAG layer can only retrieve what is in the index. Mulesoft and Apigee documentation is comprehensive for standard use but does not cover undocumented runtime behaviour: quirks in how specific connector versions handle edge cases, deprecated policy parameters that still work but are not documented, or platform-specific behaviours that are only known to developers who have been burned by them.
These gaps are not fixable at build time. The mitigation is a supplemental knowledge base: a curated set of known platform quirks, migration gotchas, and edge-case policies, maintained by the team and added to the pgvector index alongside the official docs. This base starts empty and grows as migrations surface unknown behaviour. The human review gate is the primary discovery mechanism: a flagged migration that the reviewer corrects because of a runtime quirk is a new entry for the supplemental base.