diff --git a/crates/aura-engine/src/sweep.rs b/crates/aura-engine/src/sweep.rs
index f23c1ec..b419627 100644
--- a/crates/aura-engine/src/sweep.rs
+++ b/crates/aura-engine/src/sweep.rs
@@ -1,8 +1,11 @@
-//! Grid param-sweep (C12.1): enumerate a cartesian grid over a blueprint's
-//! param-space and run each point disjointly (C1). This module owns enumeration
-//! (`GridSpace`), execution (`sweep`), and collection (`SweepFamily`); the
-//! per-point run-to-metrics closure is the author's (harness-specific sink glue
-//! the engine cannot generically own — C8/C18).
+//! Param-sweep (C12.1): enumerate a blueprint's param-space — either a cartesian
+//! `GridSpace` (a discrete per-slot lattice) or a seeded `RandomSpace` (`N` draws
+//! over typed continuous ranges) — and run each point disjointly (C1). Both
+//! enumerations implement the `Space` trait that `sweep` is generic over, so
+//! either runs through one execution path. This module owns enumeration
+//! (`GridSpace` / `RandomSpace` / the `Space` trait), execution (`sweep`), and
+//! collection (`SweepFamily`); the per-point run-to-metrics closure is the
+//! author's (harness-specific sink glue the engine cannot generically own — C8/C18).
 
 use aura_core::{zip_params, Cell, ParamSpec, Scalar, ScalarKind};
 use crate::RunReport;
diff --git a/docs/design/INDEX.md b/docs/design/INDEX.md
index 8f3bcfe..c8e989c 100644
--- a/docs/design/INDEX.md
+++ b/docs/design/INDEX.md
@@ -568,6 +568,16 @@ a streaming path *existing*, not by deleting the eager one). **Still open:**
 cross-*sim* `Arc<[T]>` sharing — one window shared zero-copy across many disjoint
 sweep sims — has no consumer until the orchestration families (axes 2–4 above:
 #66/#68/#69) are built, and remains the target for those cycles.
+**Realization (cycles 0028, 0049).** Axis 1 (param-sweep) is built. `GridSpace`
+(0028) enumerates a cartesian lattice over discrete per-slot value-lists;
+`RandomSpace` (0049) draws `N` seeded points over typed continuous `ParamRange`s
+(I64 inclusive `[lo,hi]`, F64 half-open `[lo,hi)`), validated against the
+param-space before any run. Both implement the `Space` trait the disjoint
+`sweep` / `run_indexed` core is generic over, so either enumeration runs through
+one execution path (C1: results in enumeration order, not completion order). The
+seeded sampler reuses the bit-stable `SplitMix64` as a **code-path-disjoint**
+instance from the data-edge seed RNG (the source-seam firewall, #52/#71: they
+share only the `u64` type, never a path).
 **Forbids.** Baking a specific search strategy (Bayesian/genetic) into the
 primitive — those are pluggable policies atop the atomic unit; recompiling on a
 param change.