diff --git a/src/protobin.gleam b/src/protobin.gleam
index f1227fb..32f7bb5 100644
--- a/src/protobin.gleam
+++ b/src/protobin.gleam
@@ -190,9 +190,10 @@ fn parse_varint_acc(bits: BitArray, acc: BitArray, pos: BytePos) -> ValueResult
   }
 }
 
-/// Size must be a multiple of 8.
+/// Size is in bits, usually either 32 or 64.
+///
+/// Size must be a multiple of 8, or the returned position will be incorrect.
 pub fn read_fixed(size: Int) -> ValueParser {
-  assert size % 8 == 0
   fn(bits: BitArray, pos: BytePos) -> ValueResult {
     case bits {
       <<num:bits-size(size), rest:bytes>> ->
@@ -211,9 +212,6 @@ fn read_len(bits: BitArray, len_pos: BytePos) -> ValueResult {
   ))
   let len = util.bit_array_to_uint(len)
 
-  // Just decoded a uint, so should be safe
-  assert len > 0
-
   use value <- result.try(
     bit_array.slice(from: bits, at: 0, take: len)
     |> result.map_error(fn(_) {
diff --git a/src/protobin/internal/util.gleam b/src/protobin/internal/util.gleam
index 8d91e7c..a958a15 100644
--- a/src/protobin/internal/util.gleam
+++ b/src/protobin/internal/util.gleam
@@ -3,6 +3,7 @@ import gleam/bit_array
 pub fn bit_array_to_uint(bits: BitArray) -> Int {
   let size = bit_array.bit_size(bits)
   // Interpert the entire bit array as an unsigned int
+  // It is impossible for this to crash, it interperts the entire bit array
   let assert <<n:unsigned-big-size(size)>> = bits
   n
 }