diff --git a/crates/aura-std/src/add.rs b/crates/aura-std/src/add.rs
index 2e58cca..cc1fac2 100644
--- a/crates/aura-std/src/add.rs
+++ b/crates/aura-std/src/add.rs
@@ -6,6 +6,16 @@ use aura_core::{Ctx, FieldSpec, Firing, InputSpec, Node, NodeSchema, Scalar, Sca
 
 /// Two-input f64 sum: input 0 plus input 1. Emits `None` until both inputs
 /// have a value.
+///
+/// # Firing and warm-up
+///
+/// Both inputs are [`Firing::Any`](aura_core::Firing::Any) — a *mode-A as-of
+/// join*: the node fires on every cycle in which either leg is fresh (once both
+/// have produced a value), pairing the fresh leg with the held value of the
+/// other. Until both legs have a value it emits `None` (no cold-leg-as-`0.0`).
+/// With heterogeneous sources sharing a timestamp (same `ts` from two sources =
+/// two distinct cycles, C4), a fired node emits one row per *cycle*, so a
+/// recorded combined stream may carry more than one row per timestamp.
 pub struct Add {
     out: [Scalar; 1],
 }
diff --git a/crates/aura-std/src/lincomb.rs b/crates/aura-std/src/lincomb.rs
index 8134016..ad2baad 100644
--- a/crates/aura-std/src/lincomb.rs
+++ b/crates/aura-std/src/lincomb.rs
@@ -13,6 +13,16 @@ use aura_core::{Ctx, FieldSpec, Firing, InputSpec, Node, NodeSchema, Scalar, Sca
 /// construction parameters that configure the node and fix its arity
 /// (`weights.len()` inputs, in slot order). Emits `None` until *all* inputs
 /// have a value.
+///
+/// # Firing and warm-up
+///
+/// Every input is [`Firing::Any`](aura_core::Firing::Any) — a *mode-A as-of
+/// join*: the node fires on every cycle in which any leg is fresh (once all
+/// legs have produced a value), pairing each fresh leg with the held value of
+/// the others. Until every leg has a value it emits `None` (no cold-leg-as-
+/// `0.0`). With heterogeneous sources sharing a timestamp (same `ts` from two
+/// sources = two distinct cycles, C4), a fired node emits one row per *cycle*,
+/// so a recorded combined stream may carry more than one row per timestamp.
 pub struct LinComb {
     weights: Vec<f64>,
     out: [Scalar; 1],