diff --git a/plonky2/src/plonk/circuit_builder.rs b/plonky2/src/plonk/circuit_builder.rs
index c9f2edf0..6bad9296 100644
--- a/plonky2/src/plonk/circuit_builder.rs
+++ b/plonky2/src/plonk/circuit_builder.rs
@@ -248,9 +248,10 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     /// Add a virtual verifier data, register it as a public input and set it to `self.verifier_data_public_input`.
     /// WARNING: Do not register any public input after calling this! TODO: relax this
     pub fn add_verifier_data_public_inputs(&mut self) {
-        if self.verifier_data_public_input.is_some() {
-            return;
-        }
+        assert!(
+            self.verifier_data_public_input.is_none(),
+            "add_verifier_data_public_inputs only needs to be called once"
+        );
 
         let verifier_data = VerifierCircuitTarget {
             constants_sigmas_cap: self.add_virtual_cap(self.config.fri_config.cap_height),
diff --git a/plonky2/src/recursion/cyclic_recursion.rs b/plonky2/src/recursion/cyclic_recursion.rs
index b466c034..807445d7 100644
--- a/plonky2/src/recursion/cyclic_recursion.rs
+++ b/plonky2/src/recursion/cyclic_recursion.rs
@@ -177,6 +177,8 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
 }
 
 /// Set the targets in a `CyclicRecursionTarget` to their corresponding values in a `CyclicRecursionData`.
+/// The `public_inputs` parameter let the caller specify certain public inputs (identified by their
+/// indices) which should be given specific values. The rest will default to zero.
 pub fn set_cyclic_recursion_data_target<
     F: RichField + Extendable<D>,
     C: GenericConfig<D, F = F>,