diff --git a/future-plans.md b/future-plans.md
index 4879ea5..2292ace 100644
--- a/future-plans.md
+++ b/future-plans.md
@@ -7,6 +7,14 @@
 `fs-views`, `publication-tool`). Should live in its own Gitea repo as an installable
 npm package (`npm install git+https://...`) so changes propagate rather than drift.
 
+### Hierarchical storage structure
+The current store is a flat string→value map with prefixed keys (`f:`, `c:`, `bin:`,
+etc.) as a manual namespacing convention. This should be replaced with a proper tree:
+collections as top-level keys whose values are `Record<id, object>`. Eliminates the
+prefix convention, makes collection access direct and self-documenting, and removes
+the full-scan `startsWith` pattern from every `list_*` function. Requires a one-time
+migration of existing NDJSON data. Best done as part of the shared library rewrite.
+
 ### Delta / revision tracking
 Add a delta log alongside the main snapshot file (e.g. `inventory.ndjson.deltas`)
 that records every `set`/`delete` as a timestamped entry. The main file stays a