feat(market): Taiwan (台股) suffix-only market detection + routing (#1773)

Per the maintainer review on #1772/#1773, scope this PR to market detection
and data routing only — no Taiwan stock-index / seed / pool-resolution, so a
bare code can never be silently rewritten to a .TW suffix (the index path is a
deferred follow-up with the jp/kr-style honest doc + entry-point tests).

- data_provider/base.py: _is_tw_market / _is_tw_suffix_stock, _market_tag,
  normalize_stock_code, get_daily_data + get_realtime_quote routing,
  _DAILY_MARKET_FETCHER_SUPPORT (YfinanceFetcher only), offshore fundamental path
- data_provider/yfinance_fetcher.py: _get_tw_main_indices (^TWII / ^TWOII) +
  .TW/.TWO suffix passthrough
- src/core/trading_calendar.py: XTAI / Asia/Taipei + get_market_for_stock
- src/market_context.py: detect_market + Taiwan prompt guidelines
- src/{market_phase_summary, services/stock_code_utils, core/pipeline}: tw plumbing
  (stock_code_utils only recognizes .TW/.TWO codes; no bare->suffix rewrite)
- src/services/decision_signal_extractor.py: gracefully skip tw (recognized by
  the data layer but not yet supported by the signal service) — no swallowed
  ValueError + traceback
- tests: test_tw_market_support.py + test_decision_signal_extractor.py
  (test_build_payload_skips_tw_market_gracefully — real tw skip regression)
- docs/market-support.md + CHANGELOG

Deferred follow-ups: stock index/seed + autocomplete + frontend, API market
enums + api_spec, and the service-layer market enums.

Bare numeric codes keep A-share semantics; only an explicit .TW/.TWO suffix
opts into Taiwan.

Refs #1772

data_provider/base.py

@@ -86,6 +86,8 @@ def normalize_stock_code(stock_code: str) -> str:
     - '1810.HK'     -> 'HK01810'  (normalize HK suffix to canonical prefix form)
     - '7203.T'      -> '7203.T'   (keep Japan Yahoo suffix form)
     - '005930.KS'   -> '005930.KS' (keep Korea Yahoo suffix form)
+    - '2330.TW'     -> '2330.TW'  (keep Taiwan TWSE Yahoo suffix form)
+    - '6505.TWO'    -> '6505.TWO' (keep Taiwan TPEx Yahoo suffix form)
     - 'AAPL'        -> 'AAPL'     (keep US stock ticker as-is)
 
     This function is applied at the DataProviderManager layer so that
@@ -126,13 +128,15 @@ def normalize_stock_code(stock_code: str) -> str:
             return candidate
 
     # Strip .SH/.SZ/.BJ suffix (e.g. 600519.SH -> 600519, 920748.BJ -> 920748)
-    # while preserving explicit Yahoo suffix forms for JP/KR.
+    # while preserving explicit Yahoo suffix forms for JP/KR/TW.
     if '.' in code:
         base, suffix = code.rsplit('.', 1)
         if suffix.upper() == 'T' and base.isdigit() and len(base) in (4, 5):
             return f"{base}.{suffix.upper()}"
         if suffix.upper() in ('KS', 'KQ') and base.isdigit() and len(base) == 6:
             return f"{base}.{suffix.upper()}"
+        if suffix.upper() in ('TW', 'TWO') and base.isdigit() and 4 <= len(base) <= 6:
+            return f"{base}.{suffix.upper()}"
         if suffix.upper() == 'HK' and base.isdigit() and 1 <= len(base) <= 5:
             return f"HK{base.zfill(5)}"
         if base.upper() in ('SH', 'SS', 'SZ', 'BJ') and suffix.isdigit():
@@ -190,6 +194,19 @@ def _is_kr_market(code: str) -> bool:
     return base.isdigit() and len(base) == 6
 
 
+def _is_tw_market(code: str) -> bool:
+    """判定是否为台湾 Yahoo Finance suffix 代码（TWSE 上市 2330.TW / TPEx 上柜 6505.TWO）。
+
+    台股 base 为 4-6 位（普通股 4 位，ETF/其他至 6 位，如 00878 / 006208）。
+    仅带 .TW/.TWO 后缀的代码才识别为台股，裸 6 位代码仍按 A 股语义处理。
+    """
+    normalized = (code or "").strip().upper()
+    if not normalized.endswith((".TW", ".TWO")):
+        return False
+    base = normalized.rsplit(".", 1)[0]
+    return base.isdigit() and 4 <= len(base) <= 6
+
+
 def _is_etf_code(code: str) -> bool:
     """判定 A 股 ETF 基金代码（保守规则）。"""
     normalized = normalize_stock_code(code)
@@ -230,7 +247,7 @@ def _is_meaningful_chip_distribution(chip: Any) -> bool:
 
 
 def _market_tag(code: str) -> str:
-    """返回市场标签: cn/us/hk/jp/kr."""
+    """返回市场标签: cn/us/hk/jp/kr/tw."""
     if _is_us_market(code):
         return "us"
     if _is_hk_market(code):
@@ -239,6 +256,8 @@ def _market_tag(code: str) -> str:
         return "jp"
     if _is_kr_market(code):
         return "kr"
+    if _is_tw_market(code):
+        return "tw"
     return "cn"
 
 
@@ -610,7 +629,7 @@ class DataFetcherManager:
         "TushareFetcher": {"cn", "hk"},
         "PytdxFetcher": {"cn"},
         "BaostockFetcher": {"cn"},
-        "YfinanceFetcher": {"cn", "hk", "us", "jp", "kr"},
+        "YfinanceFetcher": {"cn", "hk", "us", "jp", "kr", "tw"},
         "LongbridgeFetcher": {"hk", "us"},
         "FinnhubFetcher": {"us"},
         "AlphaVantageFetcher": {"us"},
@@ -1247,14 +1266,15 @@ class DataFetcherManager:
         is_hk = (not is_us) and _is_hk_market(stock_code)
         is_jp = (not is_us) and (not is_hk) and _is_jp_market(stock_code)
         is_kr = (not is_us) and (not is_hk) and _is_kr_market(stock_code)
-        market = "us" if is_us else "hk" if is_hk else "jp" if is_jp else "kr" if is_kr else "cn"
+        is_tw = (not is_us) and (not is_hk) and _is_tw_market(stock_code)
+        market = "us" if is_us else "hk" if is_hk else "jp" if is_jp else "kr" if is_kr else "tw" if is_tw else "cn"
         if market != "cn":
             fetchers = self._filter_daily_fetchers_for_market(fetchers, market)
         fetchers = self._filter_fetchers_by_capability(fetchers, capability="daily_data")
         total_fetchers = len(fetchers)
 
         if total_fetchers == 0:
-            market_label = "美股指数" if is_us_index else "美股" if is_us else "港股" if is_hk else "A股"
+            market_label = "美股指数" if is_us_index else "美股" if is_us else "港股" if is_hk else "台股" if is_tw else "A股"
             error_summary = f"{market_label} {stock_code} 获取失败:\n暂无可用数据源"
             logger.error(f"[数据源终止] {stock_code} 获取失败: {error_summary}")
             raise DataFetchError(error_summary)
@@ -1683,9 +1703,10 @@ class DataFetcherManager:
         is_hk = (not is_us) and _is_hk_market(stock_code)
         is_jp = (not is_us) and (not is_hk) and _is_jp_market(stock_code)
         is_kr = (not is_us) and (not is_hk) and _is_kr_market(stock_code)
+        is_tw = (not is_us) and (not is_hk) and _is_tw_market(stock_code)
 
-        if is_jp or is_kr:
-            market_label = "日股" if is_jp else "韩股"
+        if is_jp or is_kr or is_tw:
+            market_label = "日股" if is_jp else "韩股" if is_kr else "台股"
             quote = self._try_fetcher_quote(stock_code, "YfinanceFetcher")
             if quote is not None:
                 logger.info(f"[实时行情] {market_label} {stock_code} 成功获取 (来源: YfinanceFetcher)")
@@ -2947,7 +2968,7 @@ class DataFetcherManager:
         stock_code = normalize_stock_code(stock_code)
         market = _market_tag(stock_code)
         is_etf = _is_etf_code(stock_code)
-        if market in {"us", "hk", "jp", "kr"}:
+        if market in {"us", "hk", "jp", "kr", "tw"}:
             return self._build_offshore_fundamental_context(
                 stock_code,
                 market=market,

data_provider/yfinance_fetcher.py

@@ -90,6 +90,19 @@ class YfinanceFetcher(BaseFetcher):
             return base.isdigit() and len(base) == 6
         return False
 
+    @staticmethod
+    def _is_tw_suffix_stock(stock_code: str) -> bool:
+        """Return True for supported Taiwan suffix-only Yahoo symbols (TWSE `.TW` / TPEx `.TWO`).
+
+        Taiwan base codes are 4-6 digits (common stocks 4, ETFs/others up to 6,
+        e.g. 00878 / 006208), wider than the JP `.T` range.
+        """
+        code = (stock_code or "").strip().upper()
+        if code.endswith((".TW", ".TWO")):
+            base = code.rsplit(".", 1)[0]
+            return base.isdigit() and 4 <= len(base) <= 6
+        return False
+
     def _convert_stock_code(self, stock_code: str) -> str:
         """
         转换股票代码为 Yahoo Finance 格式
@@ -127,9 +140,9 @@ class YfinanceFetcher(BaseFetcher):
             logger.debug(f"识别为美股代码: {code}")
             return code
 
-        # 日股/韩股 MVP：显式 Yahoo Finance suffix-only 代码，原样传给 Yahoo。
-        if self._is_jp_kr_suffix_stock(code):
-            logger.debug(f"识别为日韩 Yahoo suffix 代码: {code}")
+        # 日股/韩股/台股 MVP：显式 Yahoo Finance suffix-only 代码，原样传给 Yahoo。
+        if self._is_jp_kr_suffix_stock(code) or self._is_tw_suffix_stock(code):
+            logger.debug(f"识别为日韩台 Yahoo suffix 代码: {code}")
             return code
 
         # 港股：hk前缀 -> .HK后缀
@@ -350,6 +363,8 @@ class YfinanceFetcher(BaseFetcher):
             return self._get_jp_main_indices(yf)
         if region == "kr":
             return self._get_kr_main_indices(yf)
+        if region == "tw":
+            return self._get_tw_main_indices(yf)
 
         # A 股指数：akshare 代码 -> (yfinance 代码, 显示名称)
         yf_mapping = {
@@ -486,6 +501,29 @@ class YfinanceFetcher(BaseFetcher):
             logger.error(f"[Yfinance] 获取韩国指数行情失败: {e}")
         return None
 
+    def _get_tw_main_indices(self, yf) -> Optional[List[Dict[str, Any]]]:
+        """获取台湾主要指数行情（加权指数 ^TWII、柜买指数 ^TWOII），复用 _fetch_yf_ticker_data。"""
+        tw_indices = {
+            'TWII': ('^TWII', '台湾加权指数'),
+            'TWOII': ('^TWOII', '台湾柜买指数'),
+        }
+        results = []
+        try:
+            for code, (yf_symbol, name) in tw_indices.items():
+                try:
+                    item = self._fetch_yf_ticker_data(yf, yf_symbol, name, code)
+                    if item:
+                        results.append(item)
+                        logger.debug(f"[Yfinance] 获取台湾指数 {name} 成功")
+                except Exception as e:
+                    logger.warning(f"[Yfinance] 获取台湾指数 {name} 失败: {e}")
+            if results:
+                logger.info(f"[Yfinance] 成功获取 {len(results)} 个台湾指数行情")
+                return results
+        except Exception as e:
+            logger.error(f"[Yfinance] 获取台湾指数行情失败: {e}")
+        return None
+
     def _is_us_stock(self, stock_code: str) -> bool:
         """
         判断代码是否为美股股票（排除美股指数）。
@@ -754,8 +792,12 @@ class YfinanceFetcher(BaseFetcher):
                 index_name=index_name,
             )
 
-        # 仅处理美股股票或 JP/KR suffix-only 股票
-        if not (self._is_us_stock(stock_code) or self._is_jp_kr_suffix_stock(stock_code)):
+        # 仅处理美股股票或 JP/KR/TW suffix-only 股票
+        if not (
+            self._is_us_stock(stock_code)
+            or self._is_jp_kr_suffix_stock(stock_code)
+            or self._is_tw_suffix_stock(stock_code)
+        ):
             logger.debug(f"[Yfinance] {stock_code} 不是美股或日韩 suffix 代码，跳过")
             return None
 

docs/CHANGELOG.md

@@ -14,6 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 - [改进] #1595 P1 新增 prompt cache telemetry / analysis-path hints / diagnostics 最小配置，默认不改变 provider 请求 shape，并复用 LLM usage HMAC secret 做 domain-separated cache hint 派生。
 - [改进] 将 Docker Compose 默认内存建议从 512M 提升到 1G，并补充低配部署说明。
 - [改进] 每日分析 workflow 兼容误将 `STOCK_LIST` 配到同名 Environment variables 的场景，同时保留 Repository variables 作为推荐配置入口。
+- [新功能] #1772 新增台湾（台股）suffix-only 个股分析 MVP（**市场识别与数据路由层**）：手输 `.TW`（TWSE 上市）/ `.TWO`（TPEx 上柜）代码可走 YFinance 日线与近实时行情，补充市场识别、交易日历（XTAI / Asia/Taipei）、Prompt 语义与能力边界文档；加权指数 `^TWII`、柜买指数 `^TWOII`。台股股票索引/种子、Web 自动补全、API 市场枚举与 Portfolio/DecisionSignal 服务层放行作为后续 PR。
+- [文档] #1772 明确本次为台股 suffix 仅路由兼容改造，对齐 #1718 日韩模式；不涉及 provider/model/base URL/运行时配置变更；DecisionSignal 抽取对 `tw` 优雅跳过；回退方式为 revert 本次改动或移除 tw 入口恢复既有行为。
 <!-- 新条目格式：- [类型] 描述（类型取值：新功能/改进/修复/文档/测试/chore）-->
 <!-- 每条独立一行追加到本段末尾，无需分类标题，合并时冲突最小 -->
 

docs/market-support.md

@@ -26,3 +26,31 @@
 - 不补齐 Portfolio 的 JPY/KRW 汇率、成本、市值完整口径；相关字段仅放开市场类型以避免前后端校验拒绝。
 
 回滚方式：移除 `jp/kr` 市场识别、交易日历注册、YFinance 路由扩展、Web/API 类型放行、`scripts/stock_index_seeds/` 日韩种子索引，并删除本文档中的能力声明。
+
+## 台湾个股 suffix-only MVP（Issue #1772，Refs #1772）
+
+当前阶段支持手动输入台湾股票的 Yahoo Finance 后缀代码，进入既有个股分析、历史保存和基础报告展示链路。TWSE 上市股票使用 `.TW` 后缀，TPEx 上柜（柜买）股票使用 `.TWO` 后缀，二者折叠为同一 `tw` 市场标签。**本次仅覆盖市场识别（detection）与数据路由层**；台股股票索引/种子、Web 自动补全、前端市场类型、API 市场枚举与 Portfolio/DecisionSignal 服务层均作为后续 PR。对齐 #1718 日韩 MVP 模式。
+
+支持格式：
+
+- 上市（TWSE）：`2330.TW`、`0050.TW`
+- 上柜（TPEx / 柜买）：`6488.TWO`、`5483.TWO`
+- 代码 base 为 4-6 位数字（普通股 4 位，ETF/其他至 6 位，如 `00878.TW`、`006208.TW`），较日股 `.T` 的 4-5 位更宽。
+
+约束与边界：
+
+- **严格 suffix-only**：裸 `2330`、`00878` 等不带后缀的代码不会进入台股语义（`detect_market` / `get_market_for_stock` 仅在显式 `.TW`/`.TWO` 后缀时返回 `tw`）。本次**不引入任何台股股票索引/种子解析**，故裸码不可能经本地/远程股票池被改写为台股 suffix；该索引解析（与 jp/kr 同款的裸码命中行为）属后续 PR。
+- 台股日线和基础实时/近实时行情只走 `YfinanceFetcher`，不尝试 AkShare、Tushare、Efinance、Pytdx、Baostock 等 A 股专属数据源。
+- 基本面复用既有 offshore yfinance 轻量路径；A 股专属资金流、龙虎榜、板块等能力按 `not_supported` 降级。
+- 报告 Prompt 已增加台股市场语义（新台币、三大法人、TWSE/TPEx ±10% 涨跌停），避免套用 A 股北向资金、龙虎榜等概念。
+- 交易日历注册 `tw: XTAI / Asia/Taipei`。TWSE 为 09:00–13:30 连续交易、无午休；收盘集合竞价暂不建模，与 jp/kr 一致。若本地 `exchange-calendars` 版本缺少对应日历，既有 fail-open/fail-closed 语义保持不变。
+- 主要指数提供加权指数 `^TWII` 与柜买指数 `^TWOII`。
+
+不承诺项：
+
+- 不承诺实时行情；Yahoo Finance 数据可能延迟或字段缺失。
+- 不承诺完整基本面、行业/板块、市场宽度、涨跌家数或台股大盘复盘。
+- 本次未包含台股股票索引/种子、Web 自动补全、前端市场类型、API 市场枚举与 Portfolio/DecisionSignal 服务层放行，均作为后续 PR；数据层已识别 `tw`，DecisionSignal 抽取对 `tw` 优雅跳过（不产出信号、也不报错或刷 traceback）。
+- 不补齐 Portfolio 的 TWD 汇率、成本、市值完整口径（属上述后续 PR 范围）。
+
+回滚方式：移除 `tw` 市场识别、交易日历注册与 YFinance 路由扩展，并删除本文档中的能力声明。

src/core/pipeline.py

@@ -1462,13 +1462,13 @@ class StockAnalysisPipeline:
         }
 
     def _get_analysis_context_with_market_fallback(self, code: str) -> Optional[Dict[str, Any]]:
-        """Load analysis context, fetching JP/KR daily bars when DB has no context."""
+        """Load analysis context, fetching JP/KR/TW daily bars when DB has no context."""
         context = self.db.get_analysis_context(code)
         if isinstance(context, dict) and context:
             return context
 
         market = get_market_for_stock(normalize_stock_code(code))
-        if market not in {"jp", "kr"}:
+        if market not in {"jp", "kr", "tw"}:
             return context
 
         try:

src/core/trading_calendar.py

@@ -36,7 +36,7 @@ except ImportError:
     )
 
 # Market -> exchange code (exchange-calendars)
-MARKET_EXCHANGE = {"cn": "XSHG", "hk": "XHKG", "us": "XNYS", "jp": "XTKS", "kr": "XKRX"}
+MARKET_EXCHANGE = {"cn": "XSHG", "hk": "XHKG", "us": "XNYS", "jp": "XTKS", "kr": "XKRX", "tw": "XTAI"}
 
 # Market -> IANA timezone for "today"
 MARKET_TIMEZONE = {
@@ -45,6 +45,7 @@ MARKET_TIMEZONE = {
     "us": "America/New_York",
     "jp": "Asia/Tokyo",
     "kr": "Asia/Seoul",
+    "tw": "Asia/Taipei",
 }
 
 # P0 market phase baseline (Issue #1386). This is an intentionally small
@@ -113,7 +114,7 @@ def get_market_for_stock(code: str) -> Optional[str]:
     Infer market region for a stock code.
 
     Returns:
-        'cn' | 'hk' | 'us' | 'jp' | 'kr' | None (None = unrecognized, fail-open: treat as open)
+        'cn' | 'hk' | 'us' | 'jp' | 'kr' | 'tw' | None (None = unrecognized, fail-open: treat as open)
     """
     if not code or not isinstance(code, str):
         return None
@@ -133,6 +134,16 @@ def get_market_for_stock(code: str) -> Optional[str]:
         base = code.rsplit(".", 1)[0]
         if base.isdigit() and len(base) == 6:
             return "kr"
+    # Taiwan: TWSE `.TW` / TPEx `.TWO`, base 4-6 digits. Checked before the
+    # bare 6-digit A-share fallback so only the explicit suffix opts into TW.
+    if code.endswith(".TWO"):
+        base = code[:-4]
+        if base.isdigit() and len(base) in (4, 5, 6):
+            return "tw"
+    if code.endswith(".TW"):
+        base = code[:-3]
+        if base.isdigit() and len(base) in (4, 5, 6):
+            return "tw"
     # A-share: 6-digit numeric
     if code.isdigit() and len(code) == 6:
         return "cn"

src/market_context.py

@@ -41,6 +41,15 @@ def detect_market(stock_code: Optional[str]) -> str:
     if re.match(r'^\d{6}\.(KS|KQ)$', code):
         return "kr"
 
+    # Taiwan suffix-only symbols supported by Yahoo Finance (TWSE `.TW`, TPEx `.TWO`).
+    # Base is 4-6 digits (common stocks 4, ETFs/others up to 6, e.g. 00878, 006208).
+    # Bare 4-digit codes remain A-share fallback to avoid collision; only the
+    # explicit `.TW`/`.TWO` suffix opts a code into the Taiwan market.
+    if re.match(r'^\d{4,6}\.TWO$', code):
+        return "tw"
+    if re.match(r'^\d{4,6}\.TW$', code):
+        return "tw"
+
     # US stocks: 1-5 uppercase letters (AAPL, TSLA, GOOGL)
     # Also handles suffixed forms like BRK.B
     if re.match(r'^[A-Z]{1,5}(\.[A-Z]{1,2})?$', code):
@@ -73,6 +82,10 @@ _MARKET_ROLES = {
         "zh": "韩股",
         "en": "Korea stock",
     },
+    "tw": {
+        "zh": "台股",
+        "en": "Taiwan stock",
+    },
 }
 
 _MARKET_GUIDELINES = {
@@ -126,6 +139,21 @@ _MARKET_GUIDELINES = {
             "- Use Korea-market context: KRW FX, Bank of Korea policy, semiconductor/internet cycles, and local trading rules; do not apply China A-share concepts such as daily price-limit boards, Northbound flows, Dragon Tiger lists, or margin-financing narratives."
         ),
     },
+    "tw": {
+        "zh": (
+            "- 本次分析对象为 **台股**（台湾证券交易所上市 `.TW`，或台湾柜买中心上柜 `.TWO`）。\n"
+            "- 请按台湾市场语境分析，关注新台币（TWD）汇率、台湾央行政策、半导体/电子代工产业链、"
+            "三大法人（外资／投信／自营商）买卖超、融资融券与当冲，以及 TWSE/TPEx ±10% 涨跌停制度；"
+            "不要套用 A 股专属的北向资金、龙虎榜等概念（台股的法人结构与资金流口径与 A 股不同）。"
+        ),
+        "en": (
+            "- This analysis covers a **Taiwan stock** (TWSE-listed `.TW`, or TPEx/OTC `.TWO`).\n"
+            "- Use Taiwan-market context: TWD FX, Central Bank of the ROC policy, the semiconductor/"
+            "electronics-foundry supply chain, the three institutional investor groups (foreign / "
+            "investment-trust / dealer), margin trading and day trading, and the TWSE/TPEx ±10% daily "
+            "price limit; do not apply China A-share-specific concepts such as Northbound flows or Dragon Tiger lists."
+        ),
+    },
 }
 
 

src/market_phase_summary.py

@@ -56,11 +56,13 @@ _MARKET_LABELS_ZH = {
     "cn": "A股",
     "hk": "港股",
     "us": "美股",
+    "tw": "台股",
 }
 _MARKET_LABELS_EN = {
     "cn": "A-shares",
     "hk": "Hong Kong",
     "us": "US",
+    "tw": "Taiwan",
 }
 _PHASE_LABELS_ZH = {
     "premarket": "盘前",
@@ -140,7 +142,7 @@ def rebuild_market_phase_summary_for_stock_code(
         return None
 
     market = get_market_for_stock(str(stock_code or "").strip())
-    if market not in {"jp", "kr"}:
+    if market not in {"jp", "kr", "tw"}:
         return dict(summary)
 
     phase = str(summary.get("phase", "")).strip()

src/services/decision_signal_extractor.py

@@ -13,6 +13,7 @@ from src.analyzer import AnalysisResult
 from src.core.trading_calendar import get_market_for_stock
 from src.schemas.decision_action import build_action_fields
 from src.services.decision_signal_service import DecisionSignalService
+from src.services.portfolio_service import VALID_MARKETS
 from src.utils.sniper_points import extract_sniper_points
 
 
@@ -59,6 +60,16 @@ def build_decision_signal_payload_from_report(
     if not market:
         logger.warning("Skip decision signal extraction: unrecognized market stock_code=%s", raw_code)
         return None
+    if market not in VALID_MARKETS:
+        # A market the data layer recognizes (e.g. tw) but the decision-signal
+        # service layer does not yet support. Skip gracefully instead of letting
+        # create_signal raise a swallowed ValueError + noisy traceback.
+        logger.info(
+            "Skip decision signal extraction: market=%s not yet wired for signals stock_code=%s",
+            market,
+            raw_code,
+        )
+        return None
 
     dashboard = _as_mapping(getattr(result, "dashboard", None))
     sniper_points = extract_sniper_points(result)

src/services/stock_code_utils.py

@@ -30,9 +30,13 @@ _SUFFIX_DIGIT_LENS: dict = {
     ".T": (4, 5),
     ".KS": (6,),
     ".KQ": (6,),
+    # Taiwan: TWSE `.TW` and TPEx `.TWO`; base is 4-6 digits (ETFs up to 6).
+    # `.TWO` listed before `.TW` as a defensive ordering convention.
+    ".TWO": (4, 5, 6),
+    ".TW": (4, 5, 6),
 }
 
-_PRESERVE_SUFFIXES = {".T", ".KS", ".KQ"}
+_PRESERVE_SUFFIXES = {".T", ".KS", ".KQ", ".TW", ".TWO"}
 
 
 def _infer_cn_exchange(base: str) -> str:

tests/test_decision_signal_extractor.py

@@ -72,6 +72,30 @@ def _result(**overrides) -> AnalysisResult:
     return result
 
 
+def test_build_payload_skips_tw_market_gracefully() -> None:
+    """A Taiwan (`tw`) stock is recognized by the data layer but is intentionally
+    not yet wired into the DecisionSignal service layer (a deferred follow-up).
+
+    The payload builder must SKIP it (return None) without raising — locking the
+    "no swallowed ValueError + noisy traceback on every tw analysis" behavior the
+    data-layer MVP relies on. A plain action ("buy") is set so the skip is the
+    market guard, not the earlier no-action early-return.
+    """
+    result = _result(code="2330.TW", name="台积电")
+
+    payload = build_decision_signal_payload_from_report(
+        result,
+        context_snapshot=None,
+        portfolio_context=None,
+        source_report_id=None,
+        trace_id="trace-tw",
+        query_source="api",
+        report_type="full",
+    )
+
+    assert payload is None
+
+
 def test_build_payload_maps_report_context_and_price_plan() -> None:
     result = _result()
     result.market_phase_summary = {"phase": "postmarket"}

tests/test_tw_market_support.py

@@ -0,0 +1,146 @@
+# -*- coding: utf-8 -*-
+"""Regression tests for Taiwan (台股) suffix-only market support.
+
+Mirrors tests/test_jp_kr_market_support.py (Issue #1718). Taiwan stocks use the
+Yahoo Finance suffix forms ``NNNN.TW`` (TWSE-listed) and ``NNNN.TWO`` (TPEx/OTC),
+with a 4-6 digit base (wider than JP ``.T``'s 4-5 to cover ETFs like 00878 /
+006208). Bare numeric codes keep their existing A-share semantics.
+"""
+
+from unittest.mock import patch
+
+import pandas as pd
+from data_provider.base import BaseFetcher, DataFetchError, DataFetcherManager, normalize_stock_code
+from data_provider.yfinance_fetcher import YfinanceFetcher
+from src.core.trading_calendar import MARKET_EXCHANGE, MARKET_TIMEZONE, get_market_for_stock
+from src.market_context import detect_market, get_market_guidelines
+from src.services.stock_code_utils import is_code_like, normalize_code
+
+
+class _FakeFetcher(BaseFetcher):
+    def __init__(self, name: str, should_fail: bool = False):
+        self.name = name
+        self.priority = 0 if name != "YfinanceFetcher" else 4
+        self.calls = []
+        self.should_fail = should_fail
+
+    def _fetch_raw_data(self, stock_code: str, start_date: str, end_date: str) -> pd.DataFrame:
+        raise NotImplementedError
+
+    def _normalize_data(self, df: pd.DataFrame, stock_code: str) -> pd.DataFrame:
+        raise NotImplementedError
+
+    def get_daily_data(self, stock_code, start_date=None, end_date=None, days=30):
+        self.calls.append(stock_code)
+        if self.should_fail:
+            raise DataFetchError(f"{self.name} should not be called for {stock_code}")
+        return pd.DataFrame(
+            {
+                "date": [pd.Timestamp("2026-06-23")],
+                "open": [1.0],
+                "high": [1.0],
+                "low": [1.0],
+                "close": [1.0],
+                "volume": [100],
+                "amount": [100.0],
+                "pct_chg": [0.0],
+            }
+        )
+
+
+def test_normalize_and_detect_tw_suffix_codes() -> None:
+    assert normalize_stock_code("2330.tw") == "2330.TW"
+    assert normalize_stock_code("6505.two") == "6505.TWO"
+    assert normalize_stock_code("00878.tw") == "00878.TW"
+    assert normalize_stock_code("006208.tw") == "006208.TW"
+
+    assert detect_market("2330.TW") == "tw"
+    assert detect_market("0050.TW") == "tw"
+    assert detect_market("006208.TW") == "tw"  # 6-digit ETF
+    assert detect_market("6505.TWO") == "tw"
+    # Bare numeric codes must stay A-share to avoid collision with .TW opt-in.
+    assert detect_market("2330") == "cn"
+
+    assert get_market_for_stock("2330.TW") == "tw"
+    assert get_market_for_stock("6505.TWO") == "tw"
+    # A bare 6-digit code that doubles as a TW ETF (e.g. 006208) must stay
+    # A-share without the explicit .TW suffix. (Bare 4-digit codes like "2330"
+    # are unrecognized -> None / fail-open, which is existing behavior.)
+    assert get_market_for_stock("006208") == "cn"
+
+    assert is_code_like("2330.TW") is True
+    assert is_code_like("6505.TWO") is True
+    assert normalize_code("6505.TWO") == "6505.TWO"
+    assert normalize_code("2330.TW") == "2330.TW"
+
+
+def test_market_guidelines_for_tw_keep_taiwan_context() -> None:
+    tw_guidelines = get_market_guidelines("2330.TW")
+
+    assert "台股" in tw_guidelines
+    # Taiwan keeps its own positive framing (±10% limit + three institutional
+    # groups); do NOT copy the JP/KR "no A-share price-limit board" wording.
+    assert "三大法人" in tw_guidelines
+    assert ("±10%" in tw_guidelines) or ("涨跌停" in tw_guidelines)
+    # Only China A-share-specific concepts are excluded.
+    assert "北向资金" in tw_guidelines
+    assert "龙虎榜" in tw_guidelines
+
+
+def test_yfinance_keeps_tw_suffix_codes_and_indices() -> None:
+    fetcher = YfinanceFetcher()
+
+    assert fetcher._convert_stock_code("2330.TW") == "2330.TW"
+    assert fetcher._convert_stock_code("6505.TWO") == "6505.TWO"
+    assert fetcher._convert_stock_code("006208.TW") == "006208.TW"
+
+    captured = []
+
+    def fake_fetch(_yf, yf_code, name, return_code):
+        captured.append((yf_code, name, return_code))
+        return {"code": return_code, "name": name, "current": 1.0}
+
+    fetcher._fetch_yf_ticker_data = fake_fetch  # type: ignore[method-assign]
+
+    tw_indices = fetcher.get_main_indices("tw") or []
+
+    assert {item["code"] for item in tw_indices} == {"TWII", "TWOII"}
+    assert ("^TWII", "台湾加权指数", "TWII") in captured
+    assert ("^TWOII", "台湾柜买指数", "TWOII") in captured
+
+
+def test_data_fetcher_manager_routes_tw_daily_only_to_yfinance() -> None:
+    efinance = _FakeFetcher("EfinanceFetcher", should_fail=True)
+    akshare = _FakeFetcher("AkshareFetcher", should_fail=True)
+    yfinance = _FakeFetcher("YfinanceFetcher")
+    manager = DataFetcherManager(fetchers=[efinance, akshare, yfinance])
+
+    with patch("data_provider.base.record_provider_run_started"), patch("data_provider.base.record_provider_run"):
+        tw_df, tw_source = manager.get_daily_data("2330.TW")
+        two_df, two_source = manager.get_daily_data("6505.TWO")
+
+    assert tw_source == "YfinanceFetcher"
+    assert two_source == "YfinanceFetcher"
+    assert not tw_df.empty and not two_df.empty
+    assert efinance.calls == []
+    assert akshare.calls == []
+    assert yfinance.calls == ["2330.TW", "6505.TWO"]
+
+
+def test_trading_calendar_registers_tw_exchange_and_timezone() -> None:
+    assert MARKET_EXCHANGE["tw"] == "XTAI"
+    assert MARKET_TIMEZONE["tw"] == "Asia/Taipei"
+
+
+def test_tw_decision_signals_gracefully_skipped_in_data_layer_scope() -> None:
+    """Data-layer MVP scope (per maintainer): tw is a recognized market, but the
+    decision-signal / portfolio / API service layer is a deliberate follow-up.
+
+    The data layer recognizes tw, while the signal service does not yet accept it,
+    so the decision-signal extractor must SKIP tw gracefully (no signal, no noisy
+    ValueError traceback) — guarded in build_decision_signal_payload_from_report.
+    """
+    from src.services.portfolio_service import VALID_MARKETS
+
+    assert get_market_for_stock("2330.TW") == "tw"  # data layer recognizes tw
+    assert "tw" not in VALID_MARKETS  # signal/service layer intentionally deferred