diff --git a/crates/tinyflows/src/lib.rs b/crates/tinyflows/src/lib.rs
index 6cfeca86..b2572d29 100644
--- a/crates/tinyflows/src/lib.rs
+++ b/crates/tinyflows/src/lib.rs
@@ -24,6 +24,9 @@
 pub mod bindings;
 pub mod caps;
 pub mod catalog;
+/// Topologies this engine's fan-in lowering cannot execute safely, refused
+/// before a run rather than surfacing as dropped data or a hung barrier.
+pub mod compat;
 pub mod compiler;
 pub mod data;
 /// Reading a run's steps for the failures a green outcome hides: null bindings,
@@ -54,6 +57,14 @@ pub mod migrate;
 pub mod model;
 pub mod nodes;
 pub mod observability;
+/// Proving a graph's outbound arguments can resolve, by running it against
+/// mocks before an author is allowed to save it.
+///
+/// Behind `mock` because that is where the schema-aware doubles it runs on
+/// live — the check *is* a mock run, so there is nothing to compile without
+/// them.
+#[cfg(any(test, feature = "mock"))]
+pub mod preflight;
 /// Stored workflows and their run history: the durable model around a graph,
 /// and a file-backed store for it. Behind the `store` feature.
 #[cfg(any(test, feature = "store"))]