The corpus is the product
Every capability in this cursus depends on retrieval finding the right document, which means the deployment's quality ceiling is set by the documentation, not by the model.
This is the finding most operations make late and painfully. A support assistant performs badly, the team investigates the model, tunes the prompts, considers a different vendor, and eventually discovers that the answers it was retrieving were wrong, outdated or absent. The model was working correctly on bad input.
Three specific problems, all covered in the company brain cursus and all acute here.
Staleness. Support documentation is written when a feature ships and rarely revised, so a corpus contains policies superseded twice. Semantic similarity is blind to time, so the 2023 refund policy retrieves as readily as the current one.
Contradiction. The knowledge base says one thing, the help centre another, and the macro a third. All three are in the corpus.
And absence. The most common questions frequently have no documented answer, because agents learned to handle them and nobody wrote it down. The corpus covers what someone thought to document rather than what customers ask.
The practical consequence for planning: budget for documentation work as the substantial part of the project. An operation that treats the corpus as an input already available will build something that answers confidently from the wrong page.

