diff --git a/quantinuum-hugr/src/ops/leaf.rs b/quantinuum-hugr/src/ops/leaf.rs
index a5e0e6046..07476ff7a 100644
--- a/quantinuum-hugr/src/ops/leaf.rs
+++ b/quantinuum-hugr/src/ops/leaf.rs
@@ -120,6 +120,21 @@ impl TypeApplication {
             })
         }
     }
+
+    /// Returns the type of the input function.
+    pub fn input(&self) -> &PolyFuncType {
+        &self.input
+    }
+
+    /// Returns the args applied to the input function.
+    pub fn args(&self) -> &[TypeArg] {
+        &self.args
+    }
+
+    /// Returns the type of the output function.
+    pub fn output(&self) -> &PolyFuncType {
+        &self.output
+    }
 }
 
 impl Default for LeafOp {
diff --git a/quantinuum-hugr/src/types/type_param.rs b/quantinuum-hugr/src/types/type_param.rs
index e10285ae3..e6d90a249 100644
--- a/quantinuum-hugr/src/types/type_param.rs
+++ b/quantinuum-hugr/src/types/type_param.rs
@@ -36,6 +36,11 @@ impl UpperBound {
             _ => false,
         }
     }
+
+    /// Returns the value of the upper bound.
+    pub fn value(&self) -> &Option<NonZeroU64> {
+        &self.0
+    }
 }
 
 /// A *kind* of [TypeArg]. Thus, a parameter declared by a [PolyFuncType] (e.g. [OpDef]),
@@ -246,6 +251,13 @@ impl TypeArg {
     }
 }
 
+impl TypeArgVariable {
+    /// Return the index.
+    pub fn index(&self) -> usize {
+        self.idx
+    }
+}
+
 /// A serialized representation of a value of a [CustomType]
 /// restricted to equatable types.
 #[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
diff --git a/quantinuum-hugr/src/values.rs b/quantinuum-hugr/src/values.rs
index 778dffff9..cdc7058bc 100644
--- a/quantinuum-hugr/src/values.rs
+++ b/quantinuum-hugr/src/values.rs
@@ -206,6 +206,11 @@ impl CustomSerialized {
             extensions,
         }
     }
+
+    /// Returns the inner value.
+    pub fn value(&self) -> &serde_yaml::Value {
+        &self.value
+    }
 }
 
 #[typetag::serde]