diff --git a/scripts/execute.py b/scripts/execute.py
index 953a7a6..e5219c2 100644
--- a/scripts/execute.py
+++ b/scripts/execute.py
@@ -26,6 +26,14 @@ class CodexEnvironmentError(RuntimeError):
     """재시도로 해결할 수 없는 Codex CLI 환경 오류."""
 
 
+def _configure_utf8_stdio():
+    """Windows 콘솔에서도 Harness 진행 문자를 안정적으로 출력한다."""
+    for stream in (sys.stdout, sys.stderr):
+        reconfigure = getattr(stream, "reconfigure", None)
+        if reconfigure is not None:
+            reconfigure(encoding="utf-8")
+
+
 @contextlib.contextmanager
 def progress_indicator(label: str):
     """터미널 진행 표시기. with 문으로 사용하며 .elapsed 로 경과 시간을 읽는다."""
@@ -468,6 +476,7 @@ class StepExecutor:
 
 
 def main():
+    _configure_utf8_stdio()
     parser = argparse.ArgumentParser(description="Harness Step Executor")
     parser.add_argument("phase_dir", help="Phase directory name (e.g. 0-mvp)")
     parser.add_argument("--push", action="store_true", help="Push branch after completion")
diff --git a/tests/test_execute.py b/tests/test_execute.py
index de9d7c1..108354b 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -59,3 +59,22 @@ def test_feature_commit_message_is_windows_console_safe():
     )
 
     message.encode("cp949")
+
+
+def test_configure_utf8_stdio_reconfigures_both_streams(monkeypatch):
+    class ReconfigurableStream:
+        def __init__(self):
+            self.encodings = []
+
+        def reconfigure(self, *, encoding):
+            self.encodings.append(encoding)
+
+    stdout = ReconfigurableStream()
+    stderr = ReconfigurableStream()
+    monkeypatch.setattr(execute.sys, "stdout", stdout)
+    monkeypatch.setattr(execute.sys, "stderr", stderr)
+
+    execute._configure_utf8_stdio()
+
+    assert stdout.encodings == ["utf-8"]
+    assert stderr.encodings == ["utf-8"]