feat: implement daily trading mode with batch decisions (issue #57)

Add API-efficient daily trading mode for Gemini Free tier compatibility:

## Features

- **Batch Decisions**: GeminiClient.decide_batch() analyzes multiple stocks
  in a single API call using compressed JSON format
- **Daily Trading Mode**: run_daily_session() executes N sessions per day
  at configurable intervals (default: 4 sessions, 6 hours apart)
- **Mode Selection**: TRADE_MODE env var switches between daily (batch)
  and realtime (per-stock) modes
- **Requirements Log**: docs/requirements-log.md tracks user feedback
  chronologically for project evolution

## Configuration

- TRADE_MODE: "daily" (default) | "realtime"
- DAILY_SESSIONS: 1-10 (default: 4)
- SESSION_INTERVAL_HOURS: 1-24 (default: 6)

## API Efficiency

- 2 markets × 4 sessions = 8 API calls/day (within Free tier 20 calls)
- 3 markets × 4 sessions = 12 API calls/day (within Free tier 20 calls)

## Testing

- 9 new batch decision tests (all passing)
- All existing tests maintained (298 passed)

## Documentation

- docs/architecture.md: Trading Modes section with daily vs realtime
- CLAUDE.md: Requirements Management section
- docs/requirements-log.md: Initial entries for API efficiency needs

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.env.example

@@ -16,8 +16,9 @@ CONFIDENCE_THRESHOLD=80
 # Database
 DB_PATH=data/trade_logs.db
 
-# Rate Limiting
+# Rate Limiting (requests per second for KIS API)
-RATE_LIMIT_RPS=10.0
+# Reduced to 5.0 to avoid "초당 거래건수 초과" errors (EGW00201)
+RATE_LIMIT_RPS=5.0
 
 # Trading Mode (paper / live)
 MODE=paper

CLAUDE.md

@@ -53,6 +53,7 @@ Get real-time alerts for trades, circuit breakers, and system events via Telegra
 - **[Context Tree](docs/context-tree.md)** — L1-L7 hierarchical memory system
 - **[Testing](docs/testing.md)** — Test structure, coverage requirements, writing tests
 - **[Agent Policies](docs/agents.md)** — Prime directives, constraints, prohibited actions
+- **[Requirements Log](docs/requirements-log.md)** — User requirements and feedback tracking
 
 ## Core Principles
 
@@ -61,6 +62,15 @@ Get real-time alerts for trades, circuit breakers, and system events via Telegra
 3. **Issue-Driven Development** — All work goes through Gitea issues → feature branches → PRs
 4. **Agent Specialization** — Use dedicated agents for design, coding, testing, docs, review
 
+## Requirements Management
+
+User requirements and feedback are tracked in [docs/requirements-log.md](docs/requirements-log.md):
+
+- New requirements are added chronologically with dates
+- Code changes should reference related requirements
+- Helps maintain project evolution aligned with user needs
+- Preserves context across conversations and development cycles
+
 ## Project Structure
 
 ```

docs/architecture.md

@@ -2,7 +2,42 @@
 
 ## Overview
 
-Self-evolving AI trading agent for global stock markets via KIS (Korea Investment & Securities) API. The main loop in `src/main.py` orchestrates four components in a 60-second cycle per stock across multiple markets.
+Self-evolving AI trading agent for global stock markets via KIS (Korea Investment & Securities) API. The main loop in `src/main.py` orchestrates four components across multiple markets with two trading modes: daily (batch API calls) or realtime (per-stock decisions).
+
+## Trading Modes
+
+The system supports two trading frequency modes controlled by the `TRADE_MODE` environment variable:
+
+### Daily Mode (default)
+
+Optimized for Gemini Free tier API limits (20 calls/day):
+
+- **Batch decisions**: 1 API call per market per session
+- **Fixed schedule**: 4 sessions per day at 6-hour intervals (configurable)
+- **API efficiency**: Processes all stocks in a market simultaneously
+- **Use case**: Free tier users, cost-conscious deployments
+- **Configuration**:
+  ```bash
+  TRADE_MODE=daily
+  DAILY_SESSIONS=4        # Sessions per day (1-10)
+  SESSION_INTERVAL_HOURS=6  # Hours between sessions (1-24)
+  ```
+
+**Example**: With 2 markets (US, KR) and 4 sessions/day = 8 API calls/day (within 20 call limit)
+
+### Realtime Mode
+
+High-frequency trading with individual stock analysis:
+
+- **Per-stock decisions**: 1 API call per stock per cycle
+- **60-second interval**: Continuous monitoring
+- **Use case**: Production deployments with Gemini paid tier
+- **Configuration**:
+  ```bash
+  TRADE_MODE=realtime
+  ```
+
+**Note**: Realtime mode requires Gemini API subscription due to high call volume.
 
 ## Core Components
 
@@ -192,6 +227,11 @@ MAX_LOSS_PCT=3.0
 MAX_ORDER_PCT=30.0
 ENABLED_MARKETS=KR,US_NASDAQ  # Comma-separated market codes
 
+# Trading Mode (API efficiency)
+TRADE_MODE=daily              # daily | realtime
+DAILY_SESSIONS=4              # Sessions per day (daily mode only)
+SESSION_INTERVAL_HOURS=6      # Hours between sessions (daily mode only)
+
 # Telegram Notifications (optional)
 TELEGRAM_BOT_TOKEN=1234567890:ABCdefGHIjklMNOpqrsTUVwxyz
 TELEGRAM_CHAT_ID=123456789

docs/requirements-log.md

@@ -0,0 +1,28 @@
+# Requirements Log
+
+프로젝트 진화를 위한 사용자 요구사항 기록.
+
+이 문서는 시간순으로 사용자와의 대화에서 나온 요구사항과 피드백을 기록합니다.
+새로운 요구사항이 있으면 날짜와 함께 추가하세요.
+
+---
+
+## 2026-02-05
+
+### API 효율화
+- Gemini API는 귀중한 자원. 종목별 개별 호출 대신 배치 호출 필요
+- Free tier 한도(20 calls/day) 고려하여 일일 몇 차례 거래 모드로 전환
+- 배치 API 호출로 여러 종목을 한 번에 분석
+
+### 거래 모드
+- **Daily Mode**: 하루 4회 거래 세션 (6시간 간격) - Free tier 호환
+- **Realtime Mode**: 60초 간격 실시간 거래 - 유료 구독 필요
+- `TRADE_MODE` 환경변수로 모드 선택
+
+### 진화 시스템
+- 사용자 대화 내용을 문서로 기록하여 향후에도 의도 반영
+- 프롬프트 품질 검증은 별도 이슈로 다룰 예정
+
+### 문서화
+- 시스템 구조, 기능별 설명 등 코드 문서화 항상 신경쓸 것
+- 새로운 기능 추가 시 관련 문서 업데이트 필수

src/analysis/scanner.py

@@ -42,6 +42,7 @@ class MarketScanner:
         volatility_analyzer: VolatilityAnalyzer,
         context_store: ContextStore,
         top_n: int = 5,
+        max_concurrent_scans: int = 1,
     ) -> None:
         """Initialize the market scanner.
 
@@ -51,12 +52,14 @@ class MarketScanner:
             volatility_analyzer: Volatility analyzer instance
             context_store: Context store for L7 real-time data
             top_n: Number of top movers to return per market (default 5)
+            max_concurrent_scans: Max concurrent stock scans (default 1, fully serialized)
         """
         self.broker = broker
         self.overseas_broker = overseas_broker
         self.analyzer = volatility_analyzer
         self.context_store = context_store
         self.top_n = top_n
+        self._scan_semaphore = asyncio.Semaphore(max_concurrent_scans)
 
     async def scan_stock(
         self,
@@ -83,8 +86,8 @@ class MarketScanner:
                 # Convert to orderbook-like structure
                 orderbook = {
                     "output1": {
-                        "stck_prpr": price_data.get("output", {}).get("last", "0"),
+                        "stck_prpr": price_data.get("output", {}).get("last", "0") or "0",
-                        "acml_vol": price_data.get("output", {}).get("tvol", "0"),
+                        "acml_vol": price_data.get("output", {}).get("tvol", "0") or "0",
                     }
                 }
 
@@ -139,8 +142,12 @@ class MarketScanner:
 
         logger.info("Scanning %s market (%d stocks)", market.name, len(stock_codes))
 
-        # Scan all stocks concurrently (with rate limiting handled by broker)
+        # Scan stocks with bounded concurrency to prevent API rate limit burst
-        tasks = [self.scan_stock(code, market) for code in stock_codes]
+        async def _bounded_scan(code: str) -> VolatilityMetrics | None:
+            async with self._scan_semaphore:
+                return await self.scan_stock(code, market)
+
+        tasks = [_bounded_scan(code) for code in stock_codes]
         results = await asyncio.gather(*tasks)
 
         # Filter out failures and sort by momentum score

src/brain/gemini_client.py

@@ -525,3 +525,233 @@ class GeminiClient:
             DecisionCache instance or None if caching disabled
         """
         return self._cache
+
+    # ------------------------------------------------------------------
+    # Batch Decision Making (for daily trading mode)
+    # ------------------------------------------------------------------
+
+    async def decide_batch(
+        self, stocks_data: list[dict[str, Any]]
+    ) -> dict[str, TradeDecision]:
+        """Make decisions for multiple stocks in a single API call.
+
+        This is designed for daily trading mode to minimize API usage
+        when working with Gemini Free tier (20 calls/day limit).
+
+        Args:
+            stocks_data: List of market data dictionaries, each with:
+                - stock_code: Stock ticker
+                - current_price: Current price
+                - market_name: Market name (optional)
+                - foreigner_net: Foreigner net buy/sell (optional)
+
+        Returns:
+            Dictionary mapping stock_code to TradeDecision
+
+        Example:
+            >>> stocks_data = [
+            ...     {"stock_code": "AAPL", "current_price": 185.5},
+            ...     {"stock_code": "MSFT", "current_price": 420.0},
+            ... ]
+            >>> decisions = await client.decide_batch(stocks_data)
+            >>> decisions["AAPL"].action
+            'BUY'
+        """
+        if not stocks_data:
+            return {}
+
+        # Build compressed batch prompt
+        market_name = stocks_data[0].get("market_name", "stock market")
+
+        # Format stock data as compact JSON array
+        compact_stocks = []
+        for stock in stocks_data:
+            compact = {
+                "code": stock["stock_code"],
+                "price": stock["current_price"],
+            }
+            if stock.get("foreigner_net", 0) != 0:
+                compact["frgn"] = stock["foreigner_net"]
+            compact_stocks.append(compact)
+
+        data_str = json.dumps(compact_stocks, ensure_ascii=False)
+
+        prompt = (
+            f"You are a professional {market_name} trading analyst.\n"
+            "Analyze the following stocks and decide whether to BUY, SELL, or HOLD each one.\n\n"
+            f"Stock Data: {data_str}\n\n"
+            "You MUST respond with ONLY a valid JSON array in this format:\n"
+            '[{"code": "AAPL", "action": "BUY", "confidence": 85, "rationale": "..."},\n'
+            ' {"code": "MSFT", "action": "HOLD", "confidence": 50, "rationale": "..."}, ...]\n\n'
+            "Rules:\n"
+            "- Return one decision object per stock\n"
+            "- action must be exactly: BUY, SELL, or HOLD\n"
+            "- confidence must be 0-100\n"
+            "- rationale should be concise (1-2 sentences)\n"
+            "- Do NOT wrap JSON in markdown code blocks\n"
+        )
+
+        # Estimate tokens
+        token_count = self._optimizer.estimate_tokens(prompt)
+        self._total_tokens_used += token_count
+
+        logger.info(
+            "Requesting batch decision for %d stocks from Gemini",
+            len(stocks_data),
+            extra={"estimated_tokens": token_count},
+        )
+
+        try:
+            response = await self._client.aio.models.generate_content(
+                model=self._model_name,
+                contents=prompt,
+            )
+            raw = response.text
+        except Exception as exc:
+            logger.error("Gemini API error in batch decision: %s", exc)
+            # Return HOLD for all stocks on API error
+            return {
+                stock["stock_code"]: TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale=f"API error: {exc}",
+                    token_count=token_count,
+                    cached=False,
+                )
+                for stock in stocks_data
+            }
+
+        # Parse batch response
+        return self._parse_batch_response(raw, stocks_data, token_count)
+
+    def _parse_batch_response(
+        self, raw: str, stocks_data: list[dict[str, Any]], token_count: int
+    ) -> dict[str, TradeDecision]:
+        """Parse batch response into a dictionary of decisions.
+
+        Args:
+            raw: Raw response from Gemini
+            stocks_data: Original stock data list
+            token_count: Token count for the request
+
+        Returns:
+            Dictionary mapping stock_code to TradeDecision
+        """
+        if not raw or not raw.strip():
+            logger.warning("Empty batch response from Gemini — defaulting all to HOLD")
+            return {
+                stock["stock_code"]: TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale="Empty response",
+                    token_count=0,
+                    cached=False,
+                )
+                for stock in stocks_data
+            }
+
+        # Strip markdown code fences if present
+        cleaned = raw.strip()
+        match = re.search(r"```(?:json)?\s*\n?(.*?)\n?```", cleaned, re.DOTALL)
+        if match:
+            cleaned = match.group(1).strip()
+
+        try:
+            data = json.loads(cleaned)
+        except json.JSONDecodeError:
+            logger.warning("Malformed JSON in batch response — defaulting all to HOLD")
+            return {
+                stock["stock_code"]: TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale="Malformed JSON response",
+                    token_count=0,
+                    cached=False,
+                )
+                for stock in stocks_data
+            }
+
+        if not isinstance(data, list):
+            logger.warning("Batch response is not a JSON array — defaulting all to HOLD")
+            return {
+                stock["stock_code"]: TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale="Invalid response format",
+                    token_count=0,
+                    cached=False,
+                )
+                for stock in stocks_data
+            }
+
+        # Build decision map
+        decisions: dict[str, TradeDecision] = {}
+        stock_codes = {stock["stock_code"] for stock in stocks_data}
+
+        for item in data:
+            if not isinstance(item, dict):
+                continue
+
+            code = item.get("code")
+            if not code or code not in stock_codes:
+                continue
+
+            # Validate required fields
+            if not all(k in item for k in ("action", "confidence", "rationale")):
+                logger.warning("Missing fields for %s — using HOLD", code)
+                decisions[code] = TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale="Missing required fields",
+                    token_count=0,
+                    cached=False,
+                )
+                continue
+
+            action = str(item["action"]).upper()
+            if action not in VALID_ACTIONS:
+                logger.warning("Invalid action '%s' for %s — forcing HOLD", action, code)
+                action = "HOLD"
+
+            confidence = int(item["confidence"])
+            rationale = str(item["rationale"])
+
+            # Enforce confidence threshold
+            if confidence < self._confidence_threshold:
+                logger.info(
+                    "Confidence %d < threshold %d for %s — forcing HOLD",
+                    confidence,
+                    self._confidence_threshold,
+                    code,
+                )
+                action = "HOLD"
+
+            decisions[code] = TradeDecision(
+                action=action,
+                confidence=confidence,
+                rationale=rationale,
+                token_count=token_count // len(stocks_data),  # Split token cost
+                cached=False,
+            )
+            self._total_decisions += 1
+
+        # Fill in missing stocks with HOLD
+        for stock in stocks_data:
+            code = stock["stock_code"]
+            if code not in decisions:
+                logger.warning("No decision for %s in batch response — using HOLD", code)
+                decisions[code] = TradeDecision(
+                    action="HOLD",
+                    confidence=0,
+                    rationale="Not found in batch response",
+                    token_count=0,
+                    cached=False,
+                )
+
+        logger.info(
+            "Batch decision completed for %d stocks",
+            len(decisions),
+            extra={"tokens": token_count},
+        )
+
+        return decisions

src/broker/kis_api.py

@@ -55,6 +55,9 @@ class KISBroker:
         self._session: aiohttp.ClientSession | None = None
         self._access_token: str | None = None
         self._token_expires_at: float = 0.0
+        self._token_lock = asyncio.Lock()
+        self._last_refresh_attempt: float = 0.0
+        self._refresh_cooldown: float = 60.0  # Seconds (matches KIS 1/minute limit)
         self._rate_limiter = LeakyBucket(settings.RATE_LIMIT_RPS)
 
     def _get_session(self) -> aiohttp.ClientSession:
@@ -80,30 +83,54 @@ class KISBroker:
     # ------------------------------------------------------------------
 
     async def _ensure_token(self) -> str:
-        """Return a valid access token, refreshing if expired."""
+        """Return a valid access token, refreshing if expired.
+
+        Uses a lock to prevent concurrent token refresh attempts that would
+        hit the API's 1-per-minute rate limit (EGW00133).
+        """
+        # Fast path: check without lock
         now = asyncio.get_event_loop().time()
         if self._access_token and now < self._token_expires_at:
             return self._access_token
 
-        logger.info("Refreshing KIS access token")
+        # Slow path: acquire lock and refresh
-        session = self._get_session()
+        async with self._token_lock:
-        url = f"{self._base_url}/oauth2/tokenP"
+            # Re-check after acquiring lock (another coroutine may have refreshed)
-        body = {
+            now = asyncio.get_event_loop().time()
-            "grant_type": "client_credentials",
+            if self._access_token and now < self._token_expires_at:
-            "appkey": self._app_key,
+                return self._access_token
-            "appsecret": self._app_secret,
-        }
 
-        async with session.post(url, json=body) as resp:
+            # Check cooldown period (prevents hitting EGW00133: 1/minute limit)
-            if resp.status != 200:
+            time_since_last_attempt = now - self._last_refresh_attempt
-                text = await resp.text()
+            if time_since_last_attempt < self._refresh_cooldown:
-                raise ConnectionError(f"Token refresh failed ({resp.status}): {text}")
+                remaining = self._refresh_cooldown - time_since_last_attempt
-            data = await resp.json()
+                error_msg = (
+                    f"Token refresh on cooldown. "
+                    f"Retry in {remaining:.1f}s (KIS allows 1/minute)"
+                )
+                logger.warning(error_msg)
+                raise ConnectionError(error_msg)
 
-        self._access_token = data["access_token"]
+            logger.info("Refreshing KIS access token")
-        self._token_expires_at = now + data.get("expires_in", 86400) - 60  # 1-min buffer
+            self._last_refresh_attempt = now
-        logger.info("Token refreshed successfully")
+            session = self._get_session()
-        return self._access_token
+            url = f"{self._base_url}/oauth2/tokenP"
+            body = {
+                "grant_type": "client_credentials",
+                "appkey": self._app_key,
+                "appsecret": self._app_secret,
+            }
+
+            async with session.post(url, json=body) as resp:
+                if resp.status != 200:
+                    text = await resp.text()
+                    raise ConnectionError(f"Token refresh failed ({resp.status}): {text}")
+                data = await resp.json()
+
+            self._access_token = data["access_token"]
+            self._token_expires_at = now + data.get("expires_in", 86400) - 60  # 1-min buffer
+            logger.info("Token refreshed successfully")
+            return self._access_token
 
     # ------------------------------------------------------------------
     # Hash Key (required for POST bodies)
@@ -111,6 +138,7 @@ class KISBroker:
 
     async def _get_hash_key(self, body: dict[str, Any]) -> str:
         """Request a hash key from KIS for POST request body signing."""
+        await self._rate_limiter.acquire()
         session = self._get_session()
         url = f"{self._base_url}/uapi/hashkey"
         headers = {

src/config.py

@@ -37,11 +37,18 @@ class Settings(BaseSettings):
     DB_PATH: str = "data/trade_logs.db"
 
     # Rate Limiting (requests per second for KIS API)
-    RATE_LIMIT_RPS: float = 10.0
+    # Conservative limit to avoid EGW00201 "초당 거래건수 초과" errors.
+    # KIS API real limit is ~2 RPS; 2.0 provides maximum safety.
+    RATE_LIMIT_RPS: float = 2.0
 
     # Trading mode
     MODE: str = Field(default="paper", pattern="^(paper|live)$")
 
+    # Trading frequency mode (daily = batch API calls, realtime = per-stock calls)
+    TRADE_MODE: str = Field(default="daily", pattern="^(daily|realtime)$")
+    DAILY_SESSIONS: int = Field(default=4, ge=1, le=10)
+    SESSION_INTERVAL_HOURS: int = Field(default=6, ge=1, le=24)
+
     # Market selection (comma-separated market codes)
     ENABLED_MARKETS: str = "KR"
 

src/main.py

@@ -33,6 +33,35 @@ from src.notifications.telegram_client import TelegramClient
 
 logger = logging.getLogger(__name__)
 
+
+def safe_float(value: str | float | None, default: float = 0.0) -> float:
+    """Convert to float, handling empty strings and None.
+
+    Args:
+        value: Value to convert (string, float, or None)
+        default: Default value if conversion fails
+
+    Returns:
+        Converted float or default value
+
+    Examples:
+        >>> safe_float("123.45")
+        123.45
+        >>> safe_float("")
+        0.0
+        >>> safe_float(None)
+        0.0
+        >>> safe_float("invalid", 99.0)
+        99.0
+    """
+    if value is None or value == "":
+        return default
+    try:
+        return float(value)
+    except (ValueError, TypeError):
+        return default
+
+
 # Target stock codes to monitor per market
 WATCHLISTS = {
     "KR": ["005930", "000660", "035420"],  # Samsung, SK Hynix, NAVER
@@ -45,6 +74,10 @@ TRADE_INTERVAL_SECONDS = 60
 SCAN_INTERVAL_SECONDS = 60  # Scan markets every 60 seconds
 MAX_CONNECTION_RETRIES = 3
 
+# Daily trading mode constants (for Free tier API efficiency)
+DAILY_TRADE_SESSIONS = 4  # Number of trading sessions per day
+TRADE_SESSION_INTERVAL_HOURS = 6  # Hours between sessions
+
 # Full stock universe per market (for scanning)
 # In production, this would be loaded from a database or API
 STOCK_UNIVERSE = {
@@ -77,16 +110,16 @@ async def trading_cycle(
         balance_data = await broker.get_balance()
 
         output2 = balance_data.get("output2", [{}])
-        total_eval = float(output2[0].get("tot_evlu_amt", "0")) if output2 else 0
+        total_eval = safe_float(output2[0].get("tot_evlu_amt", "0")) if output2 else 0
-        total_cash = float(
+        total_cash = safe_float(
             balance_data.get("output2", [{}])[0].get("dnca_tot_amt", "0")
             if output2
             else "0"
         )
-        purchase_total = float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
+        purchase_total = safe_float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
 
-        current_price = float(orderbook.get("output1", {}).get("stck_prpr", "0"))
+        current_price = safe_float(orderbook.get("output1", {}).get("stck_prpr", "0"))
-        foreigner_net = float(orderbook.get("output1", {}).get("frgn_ntby_qty", "0"))
+        foreigner_net = safe_float(orderbook.get("output1", {}).get("frgn_ntby_qty", "0"))
     else:
         # Overseas market
         price_data = await overseas_broker.get_overseas_price(
@@ -103,11 +136,11 @@ async def trading_cycle(
         else:
             balance_info = {}
 
-        total_eval = float(balance_info.get("frcr_evlu_tota", "0") or "0")
+        total_eval = safe_float(balance_info.get("frcr_evlu_tota", "0") or "0")
-        total_cash = float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
+        total_cash = safe_float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
-        purchase_total = float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
+        purchase_total = safe_float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
 
-        current_price = float(price_data.get("output", {}).get("last", "0"))
+        current_price = safe_float(price_data.get("output", {}).get("last", "0"))
         foreigner_net = 0.0  # Not available for overseas
 
     # Calculate daily P&L %
@@ -292,6 +325,239 @@ async def trading_cycle(
         )
 
 
+async def run_daily_session(
+    broker: KISBroker,
+    overseas_broker: OverseasBroker,
+    brain: GeminiClient,
+    risk: RiskManager,
+    db_conn: Any,
+    decision_logger: DecisionLogger,
+    context_store: ContextStore,
+    criticality_assessor: CriticalityAssessor,
+    telegram: TelegramClient,
+    settings: Settings,
+) -> None:
+    """Execute one daily trading session.
+
+    Designed for API efficiency with Gemini Free tier:
+    - Batch decision making (1 API call per market)
+    - Runs N times per day at fixed intervals
+    - Minimizes API usage while maintaining trading capability
+    """
+    # Get currently open markets
+    open_markets = get_open_markets(settings.enabled_market_list)
+
+    if not open_markets:
+        logger.info("No markets open for this session")
+        return
+
+    logger.info("Starting daily trading session for %d markets", len(open_markets))
+
+    # Process each open market
+    for market in open_markets:
+        # Get watchlist for this market
+        watchlist = WATCHLISTS.get(market.code, [])
+        if not watchlist:
+            logger.debug("No watchlist for market %s", market.code)
+            continue
+
+        logger.info("Processing market: %s (%d stocks)", market.name, len(watchlist))
+
+        # Collect market data for all stocks in the watchlist
+        stocks_data = []
+        for stock_code in watchlist:
+            try:
+                if market.is_domestic:
+                    orderbook = await broker.get_orderbook(stock_code)
+                    current_price = safe_float(orderbook.get("output1", {}).get("stck_prpr", "0"))
+                    foreigner_net = safe_float(
+                        orderbook.get("output1", {}).get("frgn_ntby_qty", "0")
+                    )
+                else:
+                    price_data = await overseas_broker.get_overseas_price(
+                        market.exchange_code, stock_code
+                    )
+                    current_price = safe_float(price_data.get("output", {}).get("last", "0"))
+                    foreigner_net = 0.0
+
+                stocks_data.append(
+                    {
+                        "stock_code": stock_code,
+                        "market_name": market.name,
+                        "current_price": current_price,
+                        "foreigner_net": foreigner_net,
+                    }
+                )
+            except Exception as exc:
+                logger.error("Failed to fetch data for %s: %s", stock_code, exc)
+                continue
+
+        if not stocks_data:
+            logger.warning("No valid stock data for market %s", market.code)
+            continue
+
+        # Get batch decisions (1 API call for all stocks in this market)
+        logger.info("Requesting batch decision for %d stocks in %s", len(stocks_data), market.name)
+        decisions = await brain.decide_batch(stocks_data)
+
+        # Get balance data once for the market
+        if market.is_domestic:
+            balance_data = await broker.get_balance()
+            output2 = balance_data.get("output2", [{}])
+            total_eval = safe_float(output2[0].get("tot_evlu_amt", "0")) if output2 else 0
+            total_cash = safe_float(output2[0].get("dnca_tot_amt", "0")) if output2 else 0
+            purchase_total = safe_float(output2[0].get("pchs_amt_smtl_amt", "0")) if output2 else 0
+        else:
+            balance_data = await overseas_broker.get_overseas_balance(market.exchange_code)
+            output2 = balance_data.get("output2", [{}])
+            if isinstance(output2, list) and output2:
+                balance_info = output2[0]
+            elif isinstance(output2, dict):
+                balance_info = output2
+            else:
+                balance_info = {}
+
+            total_eval = safe_float(balance_info.get("frcr_evlu_tota", "0") or "0")
+            total_cash = safe_float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
+            purchase_total = safe_float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
+
+        # Calculate daily P&L %
+        pnl_pct = (
+            ((total_eval - purchase_total) / purchase_total * 100) if purchase_total > 0 else 0.0
+        )
+
+        # Execute decisions for each stock
+        for stock_data in stocks_data:
+            stock_code = stock_data["stock_code"]
+            decision = decisions.get(stock_code)
+
+            if not decision:
+                logger.warning("No decision for %s — skipping", stock_code)
+                continue
+
+            logger.info(
+                "Decision for %s (%s): %s (confidence=%d)",
+                stock_code,
+                market.name,
+                decision.action,
+                decision.confidence,
+            )
+
+            # Log decision
+            context_snapshot = {
+                "L1": {
+                    "current_price": stock_data["current_price"],
+                    "foreigner_net": stock_data["foreigner_net"],
+                },
+                "L2": {
+                    "total_eval": total_eval,
+                    "total_cash": total_cash,
+                    "purchase_total": purchase_total,
+                    "pnl_pct": pnl_pct,
+                },
+            }
+            input_data = {
+                "current_price": stock_data["current_price"],
+                "foreigner_net": stock_data["foreigner_net"],
+                "total_eval": total_eval,
+                "total_cash": total_cash,
+                "pnl_pct": pnl_pct,
+            }
+
+            decision_logger.log_decision(
+                stock_code=stock_code,
+                market=market.code,
+                exchange_code=market.exchange_code,
+                action=decision.action,
+                confidence=decision.confidence,
+                rationale=decision.rationale,
+                context_snapshot=context_snapshot,
+                input_data=input_data,
+            )
+
+            # Execute if actionable
+            if decision.action in ("BUY", "SELL"):
+                quantity = 1
+                order_amount = stock_data["current_price"] * quantity
+
+                # Risk check
+                try:
+                    risk.validate_order(
+                        current_pnl_pct=pnl_pct,
+                        order_amount=order_amount,
+                        total_cash=total_cash,
+                    )
+                except FatFingerRejected as exc:
+                    try:
+                        await telegram.notify_fat_finger(
+                            stock_code=stock_code,
+                            order_amount=exc.order_amount,
+                            total_cash=exc.total_cash,
+                            max_pct=exc.max_pct,
+                        )
+                    except Exception as notify_exc:
+                        logger.warning("Fat finger notification failed: %s", notify_exc)
+                    continue  # Skip this order
+                except CircuitBreakerTripped as exc:
+                    logger.critical("Circuit breaker tripped — stopping session")
+                    try:
+                        await telegram.notify_circuit_breaker(
+                            pnl_pct=exc.pnl_pct,
+                            threshold=exc.threshold,
+                        )
+                    except Exception as notify_exc:
+                        logger.warning("Circuit breaker notification failed: %s", notify_exc)
+                    raise
+
+                # Send order
+                try:
+                    if market.is_domestic:
+                        result = await broker.send_order(
+                            stock_code=stock_code,
+                            order_type=decision.action,
+                            quantity=quantity,
+                            price=0,  # market order
+                        )
+                    else:
+                        result = await overseas_broker.send_overseas_order(
+                            exchange_code=market.exchange_code,
+                            stock_code=stock_code,
+                            order_type=decision.action,
+                            quantity=quantity,
+                            price=0.0,  # market order
+                        )
+                    logger.info("Order result: %s", result.get("msg1", "OK"))
+
+                    # Notify trade execution
+                    try:
+                        await telegram.notify_trade_execution(
+                            stock_code=stock_code,
+                            market=market.name,
+                            action=decision.action,
+                            quantity=quantity,
+                            price=stock_data["current_price"],
+                            confidence=decision.confidence,
+                        )
+                    except Exception as exc:
+                        logger.warning("Telegram notification failed: %s", exc)
+                except Exception as exc:
+                    logger.error("Order execution failed for %s: %s", stock_code, exc)
+                    continue
+
+            # Log trade
+            log_trade(
+                conn=db_conn,
+                stock_code=stock_code,
+                action=decision.action,
+                confidence=decision.confidence,
+                rationale=decision.rationale,
+                market=market.code,
+                exchange_code=market.exchange_code,
+            )
+
+    logger.info("Daily trading session completed")
+
+
 async def run(settings: Settings) -> None:
     """Main async loop — iterate over open markets on a timer."""
     broker = KISBroker(settings)
@@ -317,6 +583,7 @@ async def run(settings: Settings) -> None:
         volatility_analyzer=volatility_analyzer,
         context_store=context_store,
         top_n=5,
+        max_concurrent_scans=1,  # Fully serialized to avoid EGW00201
     )
 
     # Initialize latency control system
@@ -345,7 +612,7 @@ async def run(settings: Settings) -> None:
     for sig in (signal.SIGINT, signal.SIGTERM):
         loop.add_signal_handler(sig, _signal_handler)
 
-    logger.info("The Ouroboros is alive. Mode: %s", settings.MODE)
+    logger.info("The Ouroboros is alive. Mode: %s, Trading: %s", settings.MODE, settings.TRADE_MODE)
     logger.info("Enabled markets: %s", settings.enabled_market_list)
 
     # Notify system startup
@@ -355,172 +622,217 @@ async def run(settings: Settings) -> None:
         logger.warning("System startup notification failed: %s", exc)
 
     try:
-        while not shutdown.is_set():
+        # Branch based on trading mode
-            # Get currently open markets
+        if settings.TRADE_MODE == "daily":
-            open_markets = get_open_markets(settings.enabled_market_list)
+            # Daily trading mode: batch decisions at fixed intervals
+            logger.info(
+                "Daily trading mode: %d sessions every %d hours",
+                settings.DAILY_SESSIONS,
+                settings.SESSION_INTERVAL_HOURS,
+            )
 
-            if not open_markets:
+            session_interval = settings.SESSION_INTERVAL_HOURS * 3600  # Convert to seconds
-                # Notify market close for any markets that were open
-                for market_code, is_open in list(_market_states.items()):
-                    if is_open:
-                        try:
-                            from src.markets.schedule import MARKETS
 
-                            market_info = MARKETS.get(market_code)
+            while not shutdown.is_set():
-                            if market_info:
-                                await telegram.notify_market_close(market_info.name, 0.0)
-                        except Exception as exc:
-                            logger.warning("Market close notification failed: %s", exc)
-                        _market_states[market_code] = False
-
-                # No markets open — wait until next market opens
                 try:
-                    next_market, next_open_time = get_next_market_open(
+                    await run_daily_session(
-                        settings.enabled_market_list
+                        broker,
+                        overseas_broker,
+                        brain,
+                        risk,
+                        db_conn,
+                        decision_logger,
+                        context_store,
+                        criticality_assessor,
+                        telegram,
+                        settings,
                     )
-                    now = datetime.now(UTC)
+                except CircuitBreakerTripped:
-                    wait_seconds = (next_open_time - now).total_seconds()
+                    logger.critical("Circuit breaker tripped — shutting down")
-                    logger.info(
+                    shutdown.set()
-                        "No markets open. Next market: %s, opens in %.1f hours",
-                        next_market.name,
-                        wait_seconds / 3600,
-                    )
-                    await asyncio.wait_for(shutdown.wait(), timeout=wait_seconds)
-                except TimeoutError:
-                    continue  # Market should be open now
-                except ValueError as exc:
-                    logger.error("Failed to find next market open: %s", exc)
-                    await asyncio.sleep(TRADE_INTERVAL_SECONDS)
-                continue
-
-            # Process each open market
-            for market in open_markets:
-                if shutdown.is_set():
                     break
+                except Exception as exc:
+                    logger.exception("Daily session error: %s", exc)
 
-                # Notify market open if it just opened
+                # Wait for next session or shutdown
-                if not _market_states.get(market.code, False):
+                logger.info("Next session in %.1f hours", session_interval / 3600)
+                try:
+                    await asyncio.wait_for(shutdown.wait(), timeout=session_interval)
+                except TimeoutError:
+                    pass  # Normal — time for next session
+
+        else:
+            # Realtime trading mode: original per-stock loop
+            logger.info("Realtime trading mode: 60s interval per stock")
+
+            while not shutdown.is_set():
+                # Get currently open markets
+                open_markets = get_open_markets(settings.enabled_market_list)
+
+                if not open_markets:
+                    # Notify market close for any markets that were open
+                    for market_code, is_open in list(_market_states.items()):
+                        if is_open:
+                            try:
+                                from src.markets.schedule import MARKETS
+
+                                market_info = MARKETS.get(market_code)
+                                if market_info:
+                                    await telegram.notify_market_close(market_info.name, 0.0)
+                            except Exception as exc:
+                                logger.warning("Market close notification failed: %s", exc)
+                            _market_states[market_code] = False
+
+                    # No markets open — wait until next market opens
                     try:
-                        await telegram.notify_market_open(market.name)
+                        next_market, next_open_time = get_next_market_open(
-                    except Exception as exc:
+                            settings.enabled_market_list
-                        logger.warning("Market open notification failed: %s", exc)
+                        )
-                    _market_states[market.code] = True
+                        now = datetime.now(UTC)
-
+                        wait_seconds = (next_open_time - now).total_seconds()
-                # Volatility Hunter: Scan market periodically to update watchlist
+                        logger.info(
-                now_timestamp = asyncio.get_event_loop().time()
+                            "No markets open. Next market: %s, opens in %.1f hours",
-                last_scan = last_scan_time.get(market.code, 0.0)
+                            next_market.name,
-                if now_timestamp - last_scan >= SCAN_INTERVAL_SECONDS:
+                            wait_seconds / 3600,
-                    try:
+                        )
-                        # Scan all stocks in the universe
+                        await asyncio.wait_for(shutdown.wait(), timeout=wait_seconds)
-                        stock_universe = STOCK_UNIVERSE.get(market.code, [])
+                    except TimeoutError:
-                        if stock_universe:
+                        continue  # Market should be open now
-                            logger.info("Volatility Hunter: Scanning %s market", market.name)
+                    except ValueError as exc:
-                            scan_result = await market_scanner.scan_market(
+                        logger.error("Failed to find next market open: %s", exc)
-                                market, stock_universe
+                        await asyncio.sleep(TRADE_INTERVAL_SECONDS)
-                            )
-
-                            # Update watchlist with top movers
-                            current_watchlist = WATCHLISTS.get(market.code, [])
-                            updated_watchlist = market_scanner.get_updated_watchlist(
-                                current_watchlist,
-                                scan_result,
-                                max_replacements=2,
-                            )
-                            WATCHLISTS[market.code] = updated_watchlist
-
-                            logger.info(
-                                "Volatility Hunter: Watchlist updated for %s (%d top movers, %d breakouts)",
-                                market.name,
-                                len(scan_result.top_movers),
-                                len(scan_result.breakouts),
-                            )
-
-                        last_scan_time[market.code] = now_timestamp
-                    except Exception as exc:
-                        logger.error("Volatility Hunter scan failed for %s: %s", market.name, exc)
-
-                # Get watchlist for this market
-                watchlist = WATCHLISTS.get(market.code, [])
-                if not watchlist:
-                    logger.debug("No watchlist for market %s", market.code)
                     continue
 
-                logger.info("Processing market: %s (%d stocks)", market.name, len(watchlist))
+                # Process each open market
-
+                for market in open_markets:
-                # Process each stock in the watchlist
-                for stock_code in watchlist:
                     if shutdown.is_set():
                         break
 
-                    # Retry logic for connection errors
+                    # Notify market open if it just opened
-                    for attempt in range(1, MAX_CONNECTION_RETRIES + 1):
+                    if not _market_states.get(market.code, False):
                         try:
-                            await trading_cycle(
+                            await telegram.notify_market_open(market.name)
-                                broker,
-                                overseas_broker,
-                                brain,
-                                risk,
-                                db_conn,
-                                decision_logger,
-                                context_store,
-                                criticality_assessor,
-                                telegram,
-                                market,
-                                stock_code,
-                            )
-                            break  # Success — exit retry loop
-                        except CircuitBreakerTripped as exc:
-                            logger.critical("Circuit breaker tripped — shutting down")
-                            try:
-                                await telegram.notify_circuit_breaker(
-                                    pnl_pct=exc.pnl_pct,
-                                    threshold=exc.threshold,
-                                )
-                            except Exception as notify_exc:
-                                logger.warning(
-                                    "Circuit breaker notification failed: %s", notify_exc
-                                )
-                            raise
-                        except ConnectionError as exc:
-                            if attempt < MAX_CONNECTION_RETRIES:
-                                logger.warning(
-                                    "Connection error for %s (attempt %d/%d): %s",
-                                    stock_code,
-                                    attempt,
-                                    MAX_CONNECTION_RETRIES,
-                                    exc,
-                                )
-                                await asyncio.sleep(2**attempt)  # Exponential backoff
-                            else:
-                                logger.error(
-                                    "Connection error for %s (all retries exhausted): %s",
-                                    stock_code,
-                                    exc,
-                                )
-                                break  # Give up on this stock
                         except Exception as exc:
-                            logger.exception("Unexpected error for %s: %s", stock_code, exc)
+                            logger.warning("Market open notification failed: %s", exc)
-                            break  # Don't retry on unexpected errors
+                        _market_states[market.code] = True
 
-            # Log priority queue metrics periodically
+                    # Volatility Hunter: Scan market periodically to update watchlist
-            metrics = await priority_queue.get_metrics()
+                    now_timestamp = asyncio.get_event_loop().time()
-            if metrics.total_enqueued > 0:
+                    last_scan = last_scan_time.get(market.code, 0.0)
-                logger.info(
+                    if now_timestamp - last_scan >= SCAN_INTERVAL_SECONDS:
-                    "Priority queue metrics: enqueued=%d, dequeued=%d, size=%d, timeouts=%d, errors=%d",
+                        try:
-                    metrics.total_enqueued,
+                            # Scan all stocks in the universe
-                    metrics.total_dequeued,
+                            stock_universe = STOCK_UNIVERSE.get(market.code, [])
-                    metrics.current_size,
+                            if stock_universe:
-                    metrics.total_timeouts,
+                                logger.info("Volatility Hunter: Scanning %s market", market.name)
-                    metrics.total_errors,
+                                scan_result = await market_scanner.scan_market(
-                )
+                                    market, stock_universe
+                                )
 
-            # Wait for next cycle or shutdown
+                                # Update watchlist with top movers
-            try:
+                                current_watchlist = WATCHLISTS.get(market.code, [])
-                await asyncio.wait_for(shutdown.wait(), timeout=TRADE_INTERVAL_SECONDS)
+                                updated_watchlist = market_scanner.get_updated_watchlist(
-            except TimeoutError:
+                                    current_watchlist,
-                pass  # Normal — timeout means it's time for next cycle
+                                    scan_result,
+                                    max_replacements=2,
+                                )
+                                WATCHLISTS[market.code] = updated_watchlist
+
+                                logger.info(
+                                    "Volatility Hunter: Watchlist updated for %s (%d top movers, %d breakouts)",
+                                    market.name,
+                                    len(scan_result.top_movers),
+                                    len(scan_result.breakouts),
+                                )
+
+                            last_scan_time[market.code] = now_timestamp
+                        except Exception as exc:
+                            logger.error("Volatility Hunter scan failed for %s: %s", market.name, exc)
+
+                    # Get watchlist for this market
+                    watchlist = WATCHLISTS.get(market.code, [])
+                    if not watchlist:
+                        logger.debug("No watchlist for market %s", market.code)
+                        continue
+
+                    logger.info("Processing market: %s (%d stocks)", market.name, len(watchlist))
+
+                    # Process each stock in the watchlist
+                    for stock_code in watchlist:
+                        if shutdown.is_set():
+                            break
+
+                        # Retry logic for connection errors
+                        for attempt in range(1, MAX_CONNECTION_RETRIES + 1):
+                            try:
+                                await trading_cycle(
+                                    broker,
+                                    overseas_broker,
+                                    brain,
+                                    risk,
+                                    db_conn,
+                                    decision_logger,
+                                    context_store,
+                                    criticality_assessor,
+                                    telegram,
+                                    market,
+                                    stock_code,
+                                )
+                                break  # Success — exit retry loop
+                            except CircuitBreakerTripped as exc:
+                                logger.critical("Circuit breaker tripped — shutting down")
+                                try:
+                                    await telegram.notify_circuit_breaker(
+                                        pnl_pct=exc.pnl_pct,
+                                        threshold=exc.threshold,
+                                    )
+                                except Exception as notify_exc:
+                                    logger.warning(
+                                        "Circuit breaker notification failed: %s", notify_exc
+                                    )
+                                raise
+                            except ConnectionError as exc:
+                                if attempt < MAX_CONNECTION_RETRIES:
+                                    logger.warning(
+                                        "Connection error for %s (attempt %d/%d): %s",
+                                        stock_code,
+                                        attempt,
+                                        MAX_CONNECTION_RETRIES,
+                                        exc,
+                                    )
+                                    await asyncio.sleep(2**attempt)  # Exponential backoff
+                                else:
+                                    logger.error(
+                                        "Connection error for %s (all retries exhausted): %s",
+                                        stock_code,
+                                        exc,
+                                    )
+                                    break  # Give up on this stock
+                            except Exception as exc:
+                                logger.exception("Unexpected error for %s: %s", stock_code, exc)
+                                break  # Don't retry on unexpected errors
+
+                # Log priority queue metrics periodically
+                metrics = await priority_queue.get_metrics()
+                if metrics.total_enqueued > 0:
+                    logger.info(
+                        "Priority queue metrics: enqueued=%d, dequeued=%d, size=%d, timeouts=%d, errors=%d",
+                        metrics.total_enqueued,
+                        metrics.total_dequeued,
+                        metrics.current_size,
+                        metrics.total_timeouts,
+                        metrics.total_errors,
+                    )
+
+                # Wait for next cycle or shutdown
+                try:
+                    await asyncio.wait_for(shutdown.wait(), timeout=TRADE_INTERVAL_SECONDS)
+                except TimeoutError:
+                    pass  # Normal — timeout means it's time for next cycle
     finally:
+        # Clean up resources
         await broker.close()
+        await telegram.close()
         db_conn.close()
         logger.info("The Ouroboros rests.")
 

tests/test_brain.py

@@ -152,3 +152,121 @@ class TestPromptConstruction:
         assert "JSON" in prompt
         assert "action" in prompt
         assert "confidence" in prompt
+
+
+# ---------------------------------------------------------------------------
+# Batch Decision Making
+# ---------------------------------------------------------------------------
+
+
+class TestBatchDecisionParsing:
+    """Batch response parser must handle JSON arrays correctly."""
+
+    def test_parse_valid_batch_response(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [
+            {"stock_code": "AAPL", "current_price": 185.5},
+            {"stock_code": "MSFT", "current_price": 420.0},
+        ]
+        raw = """[
+            {"code": "AAPL", "action": "BUY", "confidence": 85, "rationale": "Strong momentum"},
+            {"code": "MSFT", "action": "HOLD", "confidence": 50, "rationale": "Wait for earnings"}
+        ]"""
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert len(decisions) == 2
+        assert decisions["AAPL"].action == "BUY"
+        assert decisions["AAPL"].confidence == 85
+        assert decisions["MSFT"].action == "HOLD"
+        assert decisions["MSFT"].confidence == 50
+
+    def test_parse_batch_with_markdown_wrapper(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = """```json
+[{"code": "AAPL", "action": "BUY", "confidence": 90, "rationale": "Good"}]
+```"""
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "BUY"
+        assert decisions["AAPL"].confidence == 90
+
+    def test_parse_batch_empty_response_returns_hold_for_all(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [
+            {"stock_code": "AAPL", "current_price": 185.5},
+            {"stock_code": "MSFT", "current_price": 420.0},
+        ]
+
+        decisions = client._parse_batch_response("", stocks_data, token_count=100)
+
+        assert len(decisions) == 2
+        assert decisions["AAPL"].action == "HOLD"
+        assert decisions["AAPL"].confidence == 0
+        assert decisions["MSFT"].action == "HOLD"
+
+    def test_parse_batch_malformed_json_returns_hold_for_all(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = "This is not JSON"
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "HOLD"
+        assert decisions["AAPL"].confidence == 0
+
+    def test_parse_batch_not_array_returns_hold_for_all(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = '{"code": "AAPL", "action": "BUY", "confidence": 90, "rationale": "Good"}'
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "HOLD"
+        assert decisions["AAPL"].confidence == 0
+
+    def test_parse_batch_missing_stock_gets_hold(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [
+            {"stock_code": "AAPL", "current_price": 185.5},
+            {"stock_code": "MSFT", "current_price": 420.0},
+        ]
+        # Response only has AAPL, MSFT is missing
+        raw = '[{"code": "AAPL", "action": "BUY", "confidence": 85, "rationale": "Good"}]'
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "BUY"
+        assert decisions["MSFT"].action == "HOLD"
+        assert decisions["MSFT"].confidence == 0
+
+    def test_parse_batch_invalid_action_becomes_hold(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = '[{"code": "AAPL", "action": "YOLO", "confidence": 90, "rationale": "Moon"}]'
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "HOLD"
+
+    def test_parse_batch_low_confidence_becomes_hold(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = '[{"code": "AAPL", "action": "BUY", "confidence": 65, "rationale": "Weak"}]'
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "HOLD"
+        assert decisions["AAPL"].confidence == 65
+
+    def test_parse_batch_missing_fields_gets_hold(self, settings):
+        client = GeminiClient(settings)
+        stocks_data = [{"stock_code": "AAPL", "current_price": 185.5}]
+        raw = '[{"code": "AAPL", "action": "BUY"}]'  # Missing confidence and rationale
+
+        decisions = client._parse_batch_response(raw, stocks_data, token_count=100)
+
+        assert decisions["AAPL"].action == "HOLD"
+        assert decisions["AAPL"].confidence == 0

tests/test_broker.py

@@ -49,6 +49,110 @@ class TestTokenManagement:
 
         await broker.close()
 
+    @pytest.mark.asyncio
+    async def test_concurrent_token_refresh_calls_api_once(self, settings):
+        """Multiple concurrent token requests should only call API once."""
+        broker = KISBroker(settings)
+
+        # Track how many times the mock API is called
+        call_count = [0]
+
+        def create_mock_resp():
+            call_count[0] += 1
+            mock_resp = AsyncMock()
+            mock_resp.status = 200
+            mock_resp.json = AsyncMock(
+                return_value={
+                    "access_token": "tok_concurrent",
+                    "token_type": "Bearer",
+                    "expires_in": 86400,
+                }
+            )
+            mock_resp.__aenter__ = AsyncMock(return_value=mock_resp)
+            mock_resp.__aexit__ = AsyncMock(return_value=False)
+            return mock_resp
+
+        with patch("aiohttp.ClientSession.post", return_value=create_mock_resp()):
+            # Launch 5 concurrent token requests
+            tokens = await asyncio.gather(
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+            )
+
+            # All should get the same token
+            assert all(t == "tok_concurrent" for t in tokens)
+            # API should be called only once (due to lock)
+            assert call_count[0] == 1
+
+        await broker.close()
+
+    @pytest.mark.asyncio
+    async def test_token_refresh_cooldown_prevents_rapid_retries(self, settings):
+        """Token refresh should enforce cooldown after failure (issue #54)."""
+        broker = KISBroker(settings)
+        broker._refresh_cooldown = 2.0  # Short cooldown for testing
+
+        # First refresh attempt fails with 403 (EGW00133)
+        mock_resp_403 = AsyncMock()
+        mock_resp_403.status = 403
+        mock_resp_403.text = AsyncMock(
+            return_value='{"error_code":"EGW00133","error_description":"접근토큰 발급 잠시 후 다시 시도하세요(1분당 1회)"}'
+        )
+        mock_resp_403.__aenter__ = AsyncMock(return_value=mock_resp_403)
+        mock_resp_403.__aexit__ = AsyncMock(return_value=False)
+
+        with patch("aiohttp.ClientSession.post", return_value=mock_resp_403):
+            # First attempt should fail with 403
+            with pytest.raises(ConnectionError, match="Token refresh failed"):
+                await broker._ensure_token()
+
+            # Second attempt within cooldown should fail with cooldown error
+            with pytest.raises(ConnectionError, match="Token refresh on cooldown"):
+                await broker._ensure_token()
+
+        await broker.close()
+
+    @pytest.mark.asyncio
+    async def test_token_refresh_allowed_after_cooldown(self, settings):
+        """Token refresh should be allowed after cooldown period expires."""
+        broker = KISBroker(settings)
+        broker._refresh_cooldown = 0.1  # Very short cooldown for testing
+
+        # First attempt fails
+        mock_resp_403 = AsyncMock()
+        mock_resp_403.status = 403
+        mock_resp_403.text = AsyncMock(return_value='{"error_code":"EGW00133"}')
+        mock_resp_403.__aenter__ = AsyncMock(return_value=mock_resp_403)
+        mock_resp_403.__aexit__ = AsyncMock(return_value=False)
+
+        # Second attempt succeeds
+        mock_resp_200 = AsyncMock()
+        mock_resp_200.status = 200
+        mock_resp_200.json = AsyncMock(
+            return_value={
+                "access_token": "tok_after_cooldown",
+                "expires_in": 86400,
+            }
+        )
+        mock_resp_200.__aenter__ = AsyncMock(return_value=mock_resp_200)
+        mock_resp_200.__aexit__ = AsyncMock(return_value=False)
+
+        with patch("aiohttp.ClientSession.post", return_value=mock_resp_403):
+            with pytest.raises(ConnectionError, match="Token refresh failed"):
+                await broker._ensure_token()
+
+        # Wait for cooldown to expire
+        await asyncio.sleep(0.15)
+
+        with patch("aiohttp.ClientSession.post", return_value=mock_resp_200):
+            token = await broker._ensure_token()
+            assert token == "tok_after_cooldown"
+
+        await broker.close()
+
 
 # ---------------------------------------------------------------------------
 # Network Error Handling
@@ -107,6 +211,38 @@ class TestRateLimiter:
         await broker._rate_limiter.acquire()
         await broker.close()
 
+    @pytest.mark.asyncio
+    async def test_send_order_acquires_rate_limiter_twice(self, settings):
+        """send_order must acquire rate limiter for both hash key and order call."""
+        broker = KISBroker(settings)
+        broker._access_token = "tok"
+        broker._token_expires_at = asyncio.get_event_loop().time() + 3600
+
+        # Mock hash key response
+        mock_hash_resp = AsyncMock()
+        mock_hash_resp.status = 200
+        mock_hash_resp.json = AsyncMock(return_value={"HASH": "abc123"})
+        mock_hash_resp.__aenter__ = AsyncMock(return_value=mock_hash_resp)
+        mock_hash_resp.__aexit__ = AsyncMock(return_value=False)
+
+        # Mock order response
+        mock_order_resp = AsyncMock()
+        mock_order_resp.status = 200
+        mock_order_resp.json = AsyncMock(return_value={"rt_cd": "0"})
+        mock_order_resp.__aenter__ = AsyncMock(return_value=mock_order_resp)
+        mock_order_resp.__aexit__ = AsyncMock(return_value=False)
+
+        with patch(
+            "aiohttp.ClientSession.post", side_effect=[mock_hash_resp, mock_order_resp]
+        ):
+            with patch.object(
+                broker._rate_limiter, "acquire", new_callable=AsyncMock
+            ) as mock_acquire:
+                await broker.send_order("005930", "BUY", 1, 50000)
+                assert mock_acquire.call_count == 2
+
+        await broker.close()
+
 
 # ---------------------------------------------------------------------------
 # Hash Key Generation
@@ -136,3 +272,27 @@ class TestHashKey:
             assert len(hash_key) > 0
 
         await broker.close()
+
+    @pytest.mark.asyncio
+    async def test_hash_key_acquires_rate_limiter(self, settings):
+        """_get_hash_key must go through the rate limiter to prevent burst."""
+        broker = KISBroker(settings)
+        broker._access_token = "tok"
+        broker._token_expires_at = asyncio.get_event_loop().time() + 3600
+
+        body = {"CANO": "12345678", "ACNT_PRDT_CD": "01"}
+
+        mock_resp = AsyncMock()
+        mock_resp.status = 200
+        mock_resp.json = AsyncMock(return_value={"HASH": "abc123hash"})
+        mock_resp.__aenter__ = AsyncMock(return_value=mock_resp)
+        mock_resp.__aexit__ = AsyncMock(return_value=False)
+
+        with patch("aiohttp.ClientSession.post", return_value=mock_resp):
+            with patch.object(
+                broker._rate_limiter, "acquire", new_callable=AsyncMock
+            ) as mock_acquire:
+                await broker._get_hash_key(body)
+                mock_acquire.assert_called_once()
+
+        await broker.close()

tests/test_main.py

@@ -6,7 +6,43 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 
 from src.core.risk_manager import CircuitBreakerTripped, FatFingerRejected
-from src.main import trading_cycle
+from src.main import safe_float, trading_cycle
+
+
+class TestSafeFloat:
+    """Test safe_float() helper function."""
+
+    def test_converts_valid_string(self):
+        """Test conversion of valid numeric string."""
+        assert safe_float("123.45") == 123.45
+        assert safe_float("0") == 0.0
+        assert safe_float("-99.9") == -99.9
+
+    def test_handles_empty_string(self):
+        """Test empty string returns default."""
+        assert safe_float("") == 0.0
+        assert safe_float("", 99.0) == 99.0
+
+    def test_handles_none(self):
+        """Test None returns default."""
+        assert safe_float(None) == 0.0
+        assert safe_float(None, 42.0) == 42.0
+
+    def test_handles_invalid_string(self):
+        """Test invalid string returns default."""
+        assert safe_float("invalid") == 0.0
+        assert safe_float("not_a_number", 100.0) == 100.0
+        assert safe_float("12.34.56") == 0.0
+
+    def test_handles_float_input(self):
+        """Test float input passes through."""
+        assert safe_float(123.45) == 123.45
+        assert safe_float(0.0) == 0.0
+
+    def test_custom_default(self):
+        """Test custom default value."""
+        assert safe_float("", -1.0) == -1.0
+        assert safe_float(None, 999.0) == 999.0
 
 
 class TestTradingCycleTelegramIntegration:
@@ -394,6 +430,26 @@ class TestOverseasBalanceParsing:
         broker.get_overseas_balance = AsyncMock(return_value={"output2": []})
         return broker
 
+    @pytest.fixture
+    def mock_overseas_broker_with_empty_price(self) -> MagicMock:
+        """Create mock overseas broker returning empty string for price."""
+        broker = MagicMock()
+        broker.get_overseas_price = AsyncMock(
+            return_value={"output": {"last": ""}}  # Empty string
+        )
+        broker.get_overseas_balance = AsyncMock(
+            return_value={
+                "output2": [
+                    {
+                        "frcr_evlu_tota": "10000.00",
+                        "frcr_dncl_amt_2": "5000.00",
+                        "frcr_buy_amt_smtl": "4500.00",
+                    }
+                ]
+            }
+        )
+        return broker
+
     @pytest.fixture
     def mock_domestic_broker(self) -> MagicMock:
         """Create minimal mock domestic broker."""
@@ -559,3 +615,37 @@ class TestOverseasBalanceParsing:
 
         # Verify balance API was called
         mock_overseas_broker_with_empty.get_overseas_balance.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_overseas_price_empty_string(
+        self,
+        mock_domestic_broker: MagicMock,
+        mock_overseas_broker_with_empty_price: MagicMock,
+        mock_brain_hold: MagicMock,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_overseas_market: MagicMock,
+    ) -> None:
+        """Test overseas price parsing with empty string (issue #49)."""
+        with patch("src.main.log_trade"):
+            # Should not raise ValueError, should default to 0.0
+            await trading_cycle(
+                broker=mock_domestic_broker,
+                overseas_broker=mock_overseas_broker_with_empty_price,
+                brain=mock_brain_hold,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_overseas_market,
+                stock_code="AAPL",
+            )
+
+        # Verify price API was called
+        mock_overseas_broker_with_empty_price.get_overseas_price.assert_called_once()

tests/test_volatility.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import sqlite3
 from typing import Any
 from unittest.mock import AsyncMock
@@ -338,6 +339,28 @@ class TestMarketScanner:
         assert metrics.stock_code == "AAPL"
         assert metrics.current_price == 150.50
 
+    @pytest.mark.asyncio
+    async def test_scan_stock_overseas_empty_price(
+        self,
+        scanner: MarketScanner,
+        mock_overseas_broker: OverseasBroker,
+        context_store: ContextStore,
+    ) -> None:
+        """Test scanning overseas stock with empty price string (issue #49)."""
+        mock_overseas_broker.get_overseas_price.return_value = {
+            "output": {
+                "last": "",  # Empty string
+                "tvol": "",  # Empty string
+            }
+        }
+
+        market = MARKETS["US_NASDAQ"]
+        metrics = await scanner.scan_stock("AAPL", market)
+
+        assert metrics is not None
+        assert metrics.stock_code == "AAPL"
+        assert metrics.current_price == 0.0  # Should default to 0.0
+
     @pytest.mark.asyncio
     async def test_scan_stock_error_handling(
         self,
@@ -509,3 +532,45 @@ class TestMarketScanner:
         new_additions = [code for code in updated if code not in current_watchlist]
         assert len(new_additions) <= 1
         assert len(updated) == len(current_watchlist)
+
+    @pytest.mark.asyncio
+    async def test_scan_market_respects_concurrency_limit(
+        self,
+        mock_broker: KISBroker,
+        mock_overseas_broker: OverseasBroker,
+        volatility_analyzer: VolatilityAnalyzer,
+        context_store: ContextStore,
+    ) -> None:
+        """scan_market should limit concurrent scans to max_concurrent_scans."""
+        max_concurrent = 2
+        scanner = MarketScanner(
+            broker=mock_broker,
+            overseas_broker=mock_overseas_broker,
+            volatility_analyzer=volatility_analyzer,
+            context_store=context_store,
+            top_n=5,
+            max_concurrent_scans=max_concurrent,
+        )
+
+        # Track peak concurrency
+        active_count = 0
+        peak_count = 0
+
+        original_scan = scanner.scan_stock
+
+        async def tracking_scan(code: str, market: Any) -> VolatilityMetrics:
+            nonlocal active_count, peak_count
+            active_count += 1
+            peak_count = max(peak_count, active_count)
+            await asyncio.sleep(0.05)  # Simulate API call duration
+            active_count -= 1
+            return VolatilityMetrics(code, 50000, 500, 1.0, 1.0, 1.0, 1.0, 10.0, 50.0)
+
+        scanner.scan_stock = tracking_scan  # type: ignore[method-assign]
+
+        market = MARKETS["KR"]
+        stock_codes = ["001", "002", "003", "004", "005", "006"]
+
+        await scanner.scan_market(market, stock_codes)
+
+        assert peak_count <= max_concurrent