diff --git a/crates/aura-engine/src/lib.rs b/crates/aura-engine/src/lib.rs
index 9b7f934..0d7e313 100644
--- a/crates/aura-engine/src/lib.rs
+++ b/crates/aura-engine/src/lib.rs
@@ -26,7 +26,10 @@
 //! position-event output and downstream broker nodes (C10), and the param
 //! injection + orchestration axes of the atomic sim unit
 //! (`(topology + params + data-window + seed)`, swept by optimize / walk-forward
-//! / Monte-Carlo) — its `-> metrics` reduction now ships via [`summarize`].
+//! / Monte-Carlo). The **seed** axis now ships: [`SyntheticSpec`] is a seeded
+//! `Source` producer (`Fn(u64) -> impl Source`, C12 seed-as-input) whose stream
+//! is fully seed-determined, making [`RunManifest`]'s seed a live captured input;
+//! the atomic unit's `-> metrics` reduction ships via [`summarize`].
 //!
 //! Visualization is never here: it is a downstream consumer node on the streams.