diff --git a/src/tools/fuzzing/heap-types.cpp b/src/tools/fuzzing/heap-types.cpp
index 589244bb2dd..4c065628382 100644
--- a/src/tools/fuzzing/heap-types.cpp
+++ b/src/tools/fuzzing/heap-types.cpp
@@ -263,23 +263,16 @@ struct HeapTypeGeneratorImpl {
     // by a described type. Only structs may have descriptor chains.
     if (!isDescriptor && std::get_if<StructKind>(&typeKinds.back()) &&
         remainingUncommitted && features.hasCustomDescriptors()) {
-      if (super) {
-        // If we have a supertype, our descriptor chain must be at least as
-        // long as the supertype's descriptor chain.
-        size_t length = descriptorChainLengths[*super];
-        if (rand.oneIn(2)) {
-          length += rand.upToSquared(remainingUncommitted - length);
-        }
-        descriptorChainLengths[i] = length;
-        numPlannedDescriptors += length;
-      } else {
-        // We can choose to start a brand new chain at this type.
-        if (rand.oneIn(2)) {
-          size_t length = rand.upToSquared(remainingUncommitted);
-          descriptorChainLengths[i] = length;
-          numPlannedDescriptors += length;
-        }
+      // If we have a supertype, our descriptor chain must be at least as
+      // long as the supertype's descriptor chain.
+      size_t length = super ? descriptorChainLengths[*super] : 0;
+      // If we have space, usually add at least one descriptor.
+      if (remainingUncommitted > length && !rand.oneIn(4)) {
+        length += 1 + rand.upToSquared(remainingUncommitted - length);
       }
+      assert(length <= remainingUncommitted);
+      descriptorChainLengths[i] = length;
+      numPlannedDescriptors += length;
     }
     // If this type has a descriptor chain, then we need to be able to
     // choose to generate the next type in the chain in the future.
diff --git a/test/lit/fuzz-types.test b/test/lit/fuzz-types.test
index b3683141c96..c164e32aaac 100644
--- a/test/lit/fuzz-types.test
+++ b/test/lit/fuzz-types.test
@@ -3,62 +3,58 @@
 ;; CHECK:      Running with seed 3
 ;; CHECK-NEXT: Built 20 types:
 ;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $0 (sub (shared (func (result (ref $3) i64)))))
-;; CHECK-NEXT:  (type $1 (sub (shared (struct (field (mut (ref null (shared extern)))) (field (ref null $3)) (field (mut v128)) (field v128) (field (mut (ref (shared any)))) (field (ref (shared i31)))))))
-;; CHECK-NEXT:  (type $2 (sub (func (param (ref $1)))))
-;; CHECK-NEXT:  (type $3 (shared (struct (field f32) (field (mut (ref null (shared eq)))) (field (ref (shared extern))) (field (mut (ref null (shared struct)))) (field (mut f32)) (field (mut (ref null $0))))))
-;; CHECK-NEXT:  (type $4 (sub (func (result i64))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $5 (struct (field (mut (ref $0))) (field i8) (field i31ref) (field (ref func)) (field f32)))
-;; CHECK-NEXT:  (type $6 (sub (func (param f64 (ref $7) (ref null $5) f32) (result i32))))
-;; CHECK-NEXT:  (type $7 (sub (shared (func (param (ref null $4) (ref null $6))))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $8 (struct (field (mut v128)) (field (mut (ref $5))) (field (mut v128)) (field (mut f64)) (field (mut i8))))
-;; CHECK-NEXT:  (type $9 (shared (struct (field i32) (field (mut i32)) (field (mut i16)))))
-;; CHECK-NEXT:  (type $10 (sub (func (param f32 (ref null $4) f64) (result (ref (shared struct))))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $11 (cont $16))
-;; CHECK-NEXT:  (type $12 (sub final $10 (func (param f32 funcref f64) (result (ref $9)))))
-;; CHECK-NEXT:  (type $13 (cont $19))
-;; CHECK-NEXT:  (type $14 (sub $2 (func (param (ref null (shared struct))))))
-;; CHECK-NEXT:  (type $15 (sub (struct (field (mut (ref $7))) (field (mut i8)) (field (mut v128)) (field f64) (field f64) (field i64))))
-;; CHECK-NEXT:  (type $16 (sub final $14 (func (param (ref null (shared eq))))))
-;; CHECK-NEXT:  (type $17 (sub (func (param f32 v128 (ref $13)) (result (ref $5)))))
-;; CHECK-NEXT:  (type $18 (struct (field (ref null $6)) (field (ref $17)) (field (mut f64)) (field (mut i64))))
-;; CHECK-NEXT:  (type $19 (sub $4 (func (result i64))))
+;; CHECK-NEXT:  (type $0 (shared (func (param i32 (ref null $3)) (result (ref null $3) f32 f32 i64))))
+;; CHECK-NEXT:  (type $1 (sub (shared (descriptor $2) (struct))))
+;; CHECK-NEXT:  (type $2 (sub (shared (describes $1) (descriptor $4) (struct))))
+;; CHECK-NEXT:  (type $3 (sub (array (mut f32))))
+;; CHECK-NEXT:  (type $4 (shared (describes $2) (struct)))
+;; CHECK-NEXT: )
+;; CHECK-NEXT: (rec
+;; CHECK-NEXT:  (type $5 (sub (shared (descriptor $6) (struct (field (ref null $1)) (field (ref null (shared func))) (field (mut f32)) (field i8) (field (mut i8))))))
+;; CHECK-NEXT:  (type $6 (shared (describes $5) (descriptor $7) (struct (field (mut (ref null $2))) (field (mut i8)) (field f32) (field (mut (ref $11))) (field f32))))
+;; CHECK-NEXT:  (type $7 (shared (describes $6) (descriptor $9) (struct (field i32) (field v128) (field (ref null $11)) (field (mut (ref $6))) (field (mut f64)) (field (ref (shared extern))))))
+;; CHECK-NEXT:  (type $8 (sub (struct (field (ref null $7)) (field i8) (field (mut (ref $6))) (field (mut externref)))))
+;; CHECK-NEXT:  (type $9 (shared (describes $7) (descriptor $11) (struct)))
+;; CHECK-NEXT:  (type $10 (sub (func (param f64 i32) (result f32))))
+;; CHECK-NEXT:  (type $11 (sub (shared (describes $9) (struct (field (mut i8)) (field (mut (ref $6))) (field f32) (field (ref null $2))))))
+;; CHECK-NEXT:  (type $12 (sub (descriptor $13) (struct (field i32) (field (ref null $9)) (field (mut f32)) (field (mut i16)) (field f64))))
+;; CHECK-NEXT:  (type $13 (describes $12) (struct (field externref) (field (ref $2)) (field (mut (ref $6))) (field (mut f32))))
+;; CHECK-NEXT:  (type $14 (sub final $8 (struct (field (ref $7)) (field i8) (field (mut (ref $6))) (field (mut externref)) (field (mut (ref $1))))))
+;; CHECK-NEXT: )
+;; CHECK-NEXT: (rec
+;; CHECK-NEXT:  (type $15 (sub final $8 (struct (field (ref $7)) (field i8) (field (mut (ref $6))) (field (mut externref)))))
+;; CHECK-NEXT:  (type $16 (descriptor $18) (struct (field (ref null $2)) (field i16) (field i64) (field (ref $9)) (field (mut (ref $3)))))
+;; CHECK-NEXT:  (type $17 (sub (func (param f64) (result (ref null $19)))))
+;; CHECK-NEXT:  (type $18 (describes $16) (struct))
+;; CHECK-NEXT:  (type $19 (cont $17))
 ;; CHECK-NEXT: )
 ;; CHECK-NEXT: 
 ;; CHECK-NEXT: Inhabitable types:
 ;; CHECK-NEXT: 
 ;; CHECK-NEXT: Built 20 types:
 ;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $0 (sub (shared (func (result (ref $3) i64)))))
-;; CHECK-NEXT:  (type $1 (sub (shared (struct (field (mut (ref null (shared extern)))) (field (ref null $3)) (field (mut v128)) (field v128) (field (mut (ref (shared any)))) (field (ref (shared i31)))))))
-;; CHECK-NEXT:  (type $2 (sub (func (param (ref $1)))))
-;; CHECK-NEXT:  (type $3 (shared (struct (field f32) (field (mut (ref null (shared eq)))) (field (ref null (shared extern))) (field (mut (ref null (shared struct)))) (field (mut f32)) (field (mut (ref null $0))))))
-;; CHECK-NEXT:  (type $4 (sub (func (result i64))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $5 (struct (field (mut (ref $0))) (field i8) (field i31ref) (field (ref func)) (field f32)))
-;; CHECK-NEXT:  (type $6 (sub (func (param f64 (ref $7) (ref null $5) f32) (result i32))))
-;; CHECK-NEXT:  (type $7 (sub (shared (func (param (ref null $4) (ref null $6))))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $8 (struct (field (mut v128)) (field (mut (ref $5))) (field (mut v128)) (field (mut f64)) (field (mut i8))))
-;; CHECK-NEXT:  (type $9 (shared (struct (field i32) (field (mut i32)) (field (mut i16)))))
-;; CHECK-NEXT:  (type $10 (sub (func (param f32 (ref null $4) f64) (result (ref (shared struct))))))
-;; CHECK-NEXT: )
-;; CHECK-NEXT: (rec
-;; CHECK-NEXT:  (type $11 (cont $16))
-;; CHECK-NEXT:  (type $12 (sub final $10 (func (param f32 funcref f64) (result (ref $9)))))
-;; CHECK-NEXT:  (type $13 (cont $19))
-;; CHECK-NEXT:  (type $14 (sub $2 (func (param (ref null (shared struct))))))
-;; CHECK-NEXT:  (type $15 (sub (struct (field (mut (ref $7))) (field (mut i8)) (field (mut v128)) (field f64) (field f64) (field i64))))
-;; CHECK-NEXT:  (type $16 (sub final $14 (func (param (ref null (shared eq))))))
-;; CHECK-NEXT:  (type $17 (sub (func (param f32 v128 (ref $13)) (result (ref $5)))))
-;; CHECK-NEXT:  (type $18 (struct (field (ref null $6)) (field (ref $17)) (field (mut f64)) (field (mut i64))))
-;; CHECK-NEXT:  (type $19 (sub $4 (func (result i64))))
+;; CHECK-NEXT:  (type $0 (shared (func (param i32 (ref null $3)) (result (ref null $3) f32 f32 i64))))
+;; CHECK-NEXT:  (type $1 (sub (shared (descriptor $2) (struct))))
+;; CHECK-NEXT:  (type $2 (sub (shared (describes $1) (descriptor $4) (struct))))
+;; CHECK-NEXT:  (type $3 (sub (array (mut f32))))
+;; CHECK-NEXT:  (type $4 (shared (describes $2) (struct)))
+;; CHECK-NEXT: )
+;; CHECK-NEXT: (rec
+;; CHECK-NEXT:  (type $5 (sub (shared (descriptor $6) (struct (field (ref null $1)) (field (ref null (shared func))) (field (mut f32)) (field i8) (field (mut i8))))))
+;; CHECK-NEXT:  (type $6 (shared (describes $5) (descriptor $7) (struct (field (mut (ref null $2))) (field (mut i8)) (field f32) (field (mut (ref $11))) (field f32))))
+;; CHECK-NEXT:  (type $7 (shared (describes $6) (descriptor $9) (struct (field i32) (field v128) (field (ref null $11)) (field (mut (ref null $6))) (field (mut f64)) (field (ref null (shared extern))))))
+;; CHECK-NEXT:  (type $8 (sub (struct (field (ref null $7)) (field i8) (field (mut (ref $6))) (field (mut externref)))))
+;; CHECK-NEXT:  (type $9 (shared (describes $7) (descriptor $11) (struct)))
+;; CHECK-NEXT:  (type $10 (sub (func (param f64 i32) (result f32))))
+;; CHECK-NEXT:  (type $11 (sub (shared (describes $9) (struct (field (mut i8)) (field (mut (ref null $6))) (field f32) (field (ref null $2))))))
+;; CHECK-NEXT:  (type $12 (sub (descriptor $13) (struct (field i32) (field (ref null $9)) (field (mut f32)) (field (mut i16)) (field f64))))
+;; CHECK-NEXT:  (type $13 (describes $12) (struct (field externref) (field (ref $2)) (field (mut (ref $6))) (field (mut f32))))
+;; CHECK-NEXT:  (type $14 (sub final $8 (struct (field (ref $7)) (field i8) (field (mut (ref $6))) (field (mut externref)) (field (mut (ref $1))))))
+;; CHECK-NEXT: )
+;; CHECK-NEXT: (rec
+;; CHECK-NEXT:  (type $15 (sub final $8 (struct (field (ref $7)) (field i8) (field (mut (ref $6))) (field (mut externref)))))
+;; CHECK-NEXT:  (type $16 (descriptor $18) (struct (field (ref null $2)) (field i16) (field i64) (field (ref $9)) (field (mut (ref $3)))))
+;; CHECK-NEXT:  (type $17 (sub (func (param f64) (result (ref null $19)))))
+;; CHECK-NEXT:  (type $18 (describes $16) (struct))
+;; CHECK-NEXT:  (type $19 (cont $17))
 ;; CHECK-NEXT: )