diff --git a/docs/design/INDEX.md b/docs/design/INDEX.md
index 43dda53..8cb712f 100644
--- a/docs/design/INDEX.md
+++ b/docs/design/INDEX.md
@@ -654,6 +654,36 @@ has no home in git/Gitea; determinism makes a structured registry cheap.
 Sequencing: the walking skeleton emits a manifest + metrics per run from day
 one; the registry/index is a later milestone over manifests that already exist.
 
+**Realization (cycle 0029 — the flat run registry).** The experiments-&-results
+plane shipped as `aura-registry`: an append-only JSONL store (`runs/runs.jsonl`),
+one serde_json `RunReport` (`RunManifest{commit, params, window, seed, broker}` +
+`RunMetrics`) per line, with a typed read-path (`load`) and best-first ranking
+(`rank_by`/`optimize`). C9 holds — the registry depends on `aura-engine`, never
+the reverse.
+
+**Realization (cycle 0045 — lineage as related records, #70).** The *lineage*
+depth is now realized as a **family store**: a sweep / Monte-Carlo / walk-forward
+run (the C12 axes) is persisted as a *set of related records* — each a
+`FamilyRunRecord` (a `RunReport` stamped with a shared `family_id` + `kind` +
+`ordinal`) — in a sibling JSONL (`families.jsonl`), leaving the flat `runs.jsonl`
+path and its `append`/`load`/`rank_by`/`optimize` API byte-for-byte unchanged.
+`family_id = "{name}-{counter}"` (an author-supplied name plus a per-name
+generate-and-check run index — not a content hash; re-running the same family
+mints a fresh id). `group_families` is the round-trip that re-derives a family
+from the stored links (re-listable / rankable as a unit — C21). The manifest *is*
+the re-derivation recipe (#71): no input-stream blob / path / payload enters a
+record, and a member's window is **producer-supplied** via
+`Source::bounds()`/`window_of` (eager or streamed → byte-identical lineage),
+never a materialized-`Vec` scan at the call site. CLI surface: `aura mc`,
+`aura runs families`, `aura runs family <id> [rank <metric>]`; `aura sweep` /
+`walkforward` / `mc` persist via `append_family` with an optional `--name`.
+Deferred (Non-goals): content-addressed identity + replay-dedup; the "run-diff"
+depth and ranking families against each other (cross-family, vs. within-family);
+and a live producer for the flat `runs.jsonl` standalone-run path — after this
+cycle no CLI command writes it (sweep/walkforward moved to the family store, and
+`aura run` does not persist), so `aura runs list` / `rank` await either a
+persisting `aura run` or retirement (forward-queue follow-up).
+
 ### C19 — Bootstrap: blueprint → instance (recursive)
 **Guarantee.** Construction is a distinct phase, recursive at every level. Each
 node type has a **factory** `params → sized concrete node` (e.g. `SMA(length)`