diff --git a/quantinuum-hugr/src/builder.rs b/quantinuum-hugr/src/builder.rs
index 7b8cd06bb..dec7c0b61 100644
--- a/quantinuum-hugr/src/builder.rs
+++ b/quantinuum-hugr/src/builder.rs
@@ -119,7 +119,7 @@ mod conditional;
 pub use conditional::{CaseBuilder, ConditionalBuilder};
 
 mod circuit;
-pub use circuit::CircuitBuilder;
+pub use circuit::{CircuitBuildError, CircuitBuilder};
 
 #[derive(Debug, Clone, PartialEq, Error)]
 /// Error while building the HUGR.
diff --git a/quantinuum-hugr/src/builder/circuit.rs b/quantinuum-hugr/src/builder/circuit.rs
index c3be6e15b..5cce92a85 100644
--- a/quantinuum-hugr/src/builder/circuit.rs
+++ b/quantinuum-hugr/src/builder/circuit.rs
@@ -23,6 +23,7 @@ pub struct CircuitBuilder<'a, T: ?Sized> {
 
 #[derive(Debug, Clone, PartialEq, Error)]
 /// Error in [`CircuitBuilder`]
+#[non_exhaustive]
 pub enum CircuitBuildError {
     /// Invalid index for stored wires.
     #[error("Invalid wire index {invalid_index} while attempting to add operation {}.", .op.as_ref().map(|o| o.name()).unwrap_or_default())]