| Their bet | What they claimed | What HiKEY does instead |
|---|
| RAPTOR · generated summary pyramid | multi-level summaries make retrieval smarter | uses the hierarchy the document already has · nothing generated on the retrieval path |
| TreeRAG · bidirectional traversal | traversing upward recovers the lost context | context is restored at PACK: ancestor headings ship with the evidence, no traversal needed |
| MemWalker · PageIndex · LLM navigation | reasoning picks the right branch | same coarse-to-fine narrowing by plain scores · zero LLM calls per query |
| RDR2 · learned routing | training makes the traversal accurate | no training · works out of the box on a new corpus |
| left open by all of them | tables and figures as evidence | first-class multimodal units + budget-aware packing · the genuinely new part |
Every ingredient looks simple because it is borrowed. The contribution is where the pieces sit: structure enters at BUILD and PACK instead of a smarter TRAVERSAL, and the whole system runs on one reader call. The experiments have to show the combination wins.