diff --git a/src/jarvis/tools/builtin/weather.py b/src/jarvis/tools/builtin/weather.py
index bebc3c1..dab8694 100644
--- a/src/jarvis/tools/builtin/weather.py
+++ b/src/jarvis/tools/builtin/weather.py
@@ -175,6 +175,20 @@ WMO_CODES = {
     99: "Thunderstorm with heavy hail",
 }
 
+# Korean conditions for the concise spoken reply.
+WMO_CODES_KO = {
+    0: "맑음", 1: "대체로 맑음", 2: "구름 조금", 3: "흐림",
+    45: "안개", 48: "서리 안개",
+    51: "약한 이슬비", 53: "이슬비", 55: "강한 이슬비",
+    56: "약한 어는 이슬비", 57: "강한 어는 이슬비",
+    61: "약한 비", 63: "비", 65: "강한 비",
+    66: "약한 어는 비", 67: "강한 어는 비",
+    71: "약한 눈", 73: "눈", 75: "강한 눈", 77: "싸락눈",
+    80: "약한 소나기", 81: "소나기", 82: "강한 소나기",
+    85: "약한 눈소나기", 86: "강한 눈소나기",
+    95: "천둥번개", 96: "우박 동반 천둥번개", 99: "강한 우박 천둥번개",
+}
+
 
 class WeatherTool(Tool):
     """Tool for getting current weather using Open-Meteo API."""
@@ -412,71 +426,31 @@ class WeatherTool(Tool):
             # Get weather description
             weather_desc = WMO_CODES.get(weather_code, "Unknown conditions")
 
-            # Build response text — current conditions
-            lines = [
-                f"Current weather in {location_display}:",
-                f"",
-                f"Conditions: {weather_desc}",
-            ]
-
+            # Concise, ready-to-speak Korean one-liner for the voice path. The
+            # tool result is normally re-synthesised by the LLM, but a small
+            # model rambles and leaks °F / CJK fragments, so we hand it a clean
+            # Korean sentence it can echo verbatim (one-sentence system rule).
+            _ko = WMO_CODES_KO.get(weather_code, weather_desc)
+            _short_loc = location_display.split(",")[0].strip() or location_display
+            _ko_parts = [f"지금 {_short_loc} 날씨는 {_ko}"]
             if temp_c is not None:
-                lines.append(f"Temperature: {temp_c}°C ({temp_f}°F)")
+                _t = f"기온 {round(temp_c)}도"
+                if feels_like_c is not None and round(feels_like_c) != round(temp_c):
+                    _t += f"(체감 {round(feels_like_c)}도)"
+                _ko_parts.append(_t)
+            ko_sentence = ", ".join(_ko_parts) + "입니다."
 
-            if feels_like_c is not None and feels_like_c != temp_c:
-                lines.append(f"Feels like: {feels_like_c}°C ({feels_like_f}°F)")
-
-            if humidity is not None:
-                lines.append(f"Humidity: {humidity}%")
-
-            if wind_speed is not None:
-                wind_info = f"Wind: {wind_speed} km/h"
-                if wind_gusts and wind_gusts > wind_speed:
-                    wind_info += f" (gusts up to {wind_gusts} km/h)"
-                lines.append(wind_info)
-
-            # Append today's hourly forecast (remaining hours)
-            hourly = weather_data.get("hourly", {})
-            hourly_times = hourly.get("time", [])
-            hourly_temps = hourly.get("temperature_2m", [])
-            hourly_codes = hourly.get("weather_code", [])
-
-            if hourly_times and hourly_temps:
-                # Get current hour from the current time field
-                current_time = current.get("time", "")
-                current_hour_str = current_time[11:13] if len(current_time) >= 13 else ""
-                current_hour = int(current_hour_str) if current_hour_str.isdigit() else 0
-                today_prefix = current_time[:10] if len(current_time) >= 10 else ""
-
-                hourly_lines = []
-                for i, t in enumerate(hourly_times):
-                    if not t.startswith(today_prefix):
-                        continue
-                    hour_str = t[11:13] if len(t) >= 13 else ""
-                    hour = int(hour_str) if hour_str.isdigit() else -1
-                    # Show every 3 hours from now onwards
-                    if hour > current_hour and hour % 3 == 0 and i < len(hourly_temps) and i < len(hourly_codes):
-                        desc = WMO_CODES.get(hourly_codes[i], "")
-                        hourly_lines.append(f"  {hour:02d}:00 — {hourly_temps[i]}°C, {desc}")
-
-                if hourly_lines:
-                    lines.append("")
-                    lines.append("Today's forecast (upcoming hours):")
-                    lines.extend(hourly_lines)
-
-            # Append daily forecast
-            daily = weather_data.get("daily", {})
-            daily_dates = daily.get("time", [])
-            daily_codes = daily.get("weather_code", [])
-            daily_max = daily.get("temperature_2m_max", [])
-            daily_min = daily.get("temperature_2m_min", [])
-
-            if daily_dates and daily_max and daily_min:
-                lines.append("")
-                lines.append("7-day forecast:")
-                for i, date_str in enumerate(daily_dates):
-                    if i < len(daily_max) and i < len(daily_min) and i < len(daily_codes):
-                        desc = WMO_CODES.get(daily_codes[i], "")
-                        lines.append(f"  {date_str}: {daily_min[i]}–{daily_max[i]}°C, {desc}")
+            # Build response text — concise current conditions (Korean sentence
+            # first so the model echoes it; English detail kept for any follow-up
+            # reasoning but the forecast firehose is dropped to curb rambling).
+            lines = [
+                f"한국어로 정확히 이 한 문장만 답하세요: {ko_sentence}",
+                f"(참고 데이터 — 답변에 추가하지 말 것: {location_display}, {weather_desc}, "
+                f"{temp_c}°C feels {feels_like_c}°C, humidity {humidity}%, wind {wind_speed}km/h)",
+            ]
+            # Forecast (hourly / 7-day) is intentionally omitted from the default
+            # voice reply to keep it to one spoken sentence; current conditions
+            # are what "날씨 알려줘" asks for.
 
             reply_text = "\n".join(lines)