diff --git a/crates/fj-kernel/src/algorithms/cast_ray/mod.rs b/crates/fj-kernel/src/algorithms/cast_ray/mod.rs
index 7324ff289..707355d13 100644
--- a/crates/fj-kernel/src/algorithms/cast_ray/mod.rs
+++ b/crates/fj-kernel/src/algorithms/cast_ray/mod.rs
@@ -8,6 +8,14 @@ pub use self::segment::RaySegmentHit;
 use fj_math::Point;
 
 /// Implemented by types that support ray casting
+///
+/// # Implementation Note
+///
+/// This is basically a more limited version of [`Intersect`]. It probably makes
+/// sense to migrate all of this trait's implementations to [`Intersect`] and
+/// remove this trait.
+///
+/// [`Intersect`]: super::intersect::Intersect
 pub trait CastRay<const D: usize> {
     /// The type that describes a hit of the ray on the implementing type
     type Hit;
diff --git a/crates/fj-kernel/src/algorithms/contains/mod.rs b/crates/fj-kernel/src/algorithms/contains/mod.rs
index e7ed67a27..8f986342a 100644
--- a/crates/fj-kernel/src/algorithms/contains/mod.rs
+++ b/crates/fj-kernel/src/algorithms/contains/mod.rs
@@ -1,6 +1,14 @@
 mod face_point;
 
 /// Test whether an object or shape contains another
+///
+/// # Implementation Note
+///
+/// This is basically a more limited version of [`Intersect`]. It probably makes
+/// sense to migrate all of this trait's implementations to [`Intersect`] and
+/// remove this trait.
+///
+/// [`Intersect`]: super::intersect::Intersect
 pub trait Contains<T> {
     /// Test whether an object or shape contains another
     ///