diff --git a/packages/kiri/lib/kiri/input_text/normalize.ex b/packages/kiri/lib/kiri/input_text/normalize.ex
index 3ee85ec..cbf3f3d 100644
--- a/packages/kiri/lib/kiri/input_text/normalize.ex
+++ b/packages/kiri/lib/kiri/input_text/normalize.ex
@@ -47,10 +47,8 @@ defmodule Kiri.InputText.Normalize do
 
   @spec rewrite(InputText.t(), t()) :: InputText.t()
   def rewrite(builder, rules) do
-    text = InputText.get_text(builder)
-    chars = String.to_charlist(text)
-    text_len = length(chars)
-    do_rewrite(builder, rules, chars, 0, 0, text, text_len)
+    chars = builder |> InputText.get_text() |> String.to_charlist()
+    do_rewrite(builder, rules, chars, 0, 0, length(chars))
   end
 
   # --- Parsing helpers ---
@@ -82,13 +80,13 @@ defmodule Kiri.InputText.Normalize do
   end
 
   # --- Rewrite loop ---
-  # `text` is threaded through as a parameter and only recomputed after
-  # actual replacements, avoiding the O(n²) cost of rebuilding the string
-  # on every character iteration.
+  # Iteration is driven by the original charlist (`[cp | rest]`), not the
+  # modified text. `offset` tracks the cumulative length delta so that
+  # `InputText.replace` receives correct positions.
 
-  defp do_rewrite(builder, _rules, [], _i, _offset, _text, _text_len), do: builder
+  defp do_rewrite(builder, _rules, [], _i, _offset, _text_len), do: builder
 
-  defp do_rewrite(builder, rules, [cp | rest] = chars, i, offset, text, text_len) do
+  defp do_rewrite(builder, rules, [cp | rest] = chars, i, offset, text_len) do
     max_key_len = Map.get(rules.key_lengths, cp, 0)
     remaining = text_len - (i + offset)
 
@@ -97,7 +95,6 @@ defmodule Kiri.InputText.Normalize do
         builder = InputText.replace(builder, i + offset, i + match_len + offset, replacement)
         rep_len = count_codepoints_fast(replacement)
         new_text_len = text_len + rep_len - match_len
-        text = InputText.get_text(builder)
 
         do_rewrite(
           builder,
@@ -105,34 +102,31 @@ defmodule Kiri.InputText.Normalize do
           Enum.drop(rest, match_len - 1),
           i + match_len,
           offset + rep_len - match_len,
-          text,
           new_text_len
         )
 
       :not_replaced ->
-        normalize_char(builder, rules, cp, rest, i, offset, text, text_len)
+        normalize_char(builder, rules, cp, rest, i, offset, text_len)
     end
   end
 
-  defp normalize_char(builder, rules, cp, rest, i, offset, text, text_len) do
+  defp normalize_char(builder, rules, cp, rest, i, offset, text_len) do
     nfkc = nfkc_replacement(cp, rules.ignore_normalize_set)
 
     case nfkc do
       nil ->
-        do_rewrite(builder, rules, rest, i + 1, offset, text, text_len)
+        do_rewrite(builder, rules, rest, i + 1, offset, text_len)
 
       <<^cp::utf8>> ->
-        do_rewrite(builder, rules, rest, i + 1, offset, text, text_len)
+        do_rewrite(builder, rules, rest, i + 1, offset, text_len)
 
       <<_single_cp::utf8>> ->
         builder = InputText.replace(builder, i + offset, i + 1 + offset, nfkc)
-        text = InputText.get_text(builder)
-        do_rewrite(builder, rules, rest, i + 1, offset, text, text_len)
+        do_rewrite(builder, rules, rest, i + 1, offset, text_len)
 
       _ ->
         rep_len = count_codepoints_fast(nfkc)
         builder = InputText.replace(builder, i + offset, i + 1 + offset, nfkc)
-        text = InputText.get_text(builder)
 
         do_rewrite(
           builder,
@@ -140,7 +134,6 @@ defmodule Kiri.InputText.Normalize do
           rest,
           i + 1,
           offset + rep_len - 1,
-          text,
           text_len + rep_len - 1
         )
     end
diff --git a/packages/kiri/lib/mix/tasks/kiri.convert.ex b/packages/kiri/lib/mix/tasks/kiri.convert.ex
index b044f4e..32cba10 100644
--- a/packages/kiri/lib/mix/tasks/kiri.convert.ex
+++ b/packages/kiri/lib/mix/tasks/kiri.convert.ex
@@ -18,6 +18,8 @@ defmodule Mix.Tasks.Kiri.Convert do
 
   use Mix.Task
 
+  alias Kiri.Dictionary.Converter
+
   @shortdoc "Convert a Sudachi .dic to .kiri format"
 
   @impl Mix.Task
@@ -40,7 +42,7 @@ defmodule Mix.Tasks.Kiri.Convert do
 
         Mix.shell().info("Converting #{dic_path} -> #{output_dir}")
 
-        case Kiri.Dictionary.Converter.convert(dic_path, output_dir, convert_opts) do
+        case Converter.convert(dic_path, output_dir, convert_opts) do
           :ok ->
             Mix.shell().info("Done. Output written to #{output_dir}/")