更新

.workbuddy/memory/2026-08-28.md

@@ -0,0 +1,21 @@
+# 2026-08-28 工作日志
+
+## 抖音 IM「decision=KICK」排查（服务器 116.62.23.103）
+
+**结论**：不是抖音改了 IM 规则/签名算法，是账号被安全网关风控踢下线。签名链路正常（同服务器另一账号可正常发送、读接口正常返回、凭证完整）。
+
+**关键证据**（服务器 MySQL `kefu` 库 + `/www/wwwlogs/python/douyin/error.log`）：
+- 活跃账号：id=11「随安尔乐」my_uid=7670159096859706425、id=12「抖音账号_12」my_uid=7670157997767050299，均为 Chrome/148 UA，keys/web_protect 凭证完整（len 533/459）。
+- 两个账号反复 KICK，且都在回复同一测试号「Huhao」(peer_uid=66578464308)，回复内容只是 "ss"/"jjj" 测试文本（非导流话术）。
+- 时序：KICK → create_conversation INVALID_REQUEST → 「用户未登录」→ 自动重登录 → 恢复 → 再发 → 再 KICK，形成死循环（约每 10~30 分钟一次）。
+- 读接口(get_by_user_init)正常，只有 signed 的发送(message/send)被 KICK → 签名没问题，是账号级风控。
+
+**根因判断**：抖音 2026 风控收紧（内容+设备+IP+行为+账号五维）。触发点最可能是：多账号同服务器 IP + 对同一陌生 peer 的自动回复行为；且 KICK→重登→再发 的紧循环本身会加重风控。
+
+**处理方向**：
+1. 停掉受影响账号的托管/自动回复，冷却几小时~一天。
+2. 浏览器模式手动重登，先用互关好友或「对方先发」的真实用户测发送，别再用小号对冷门 peer 反复自动回。
+3. 确认账号没在手机端同时登录（并发登录会吊销 web ticket）。
+4. 后续可选代码改进：KICK 后对同一会话加冷却（重登后暂不重发），打断紧循环。
+
+**环境备注**：后端用 MySQL(`KEFU_DB_TYPE=mysql`)，`kefu.db`/`kefu1.db` 是遗留 SQLite（kefu.db 已损坏，非活跃库，可忽略）。

backend/main.py

@@ -84,6 +84,7 @@ from rpa_engine.credential import (
     assess_account_credential,
     build_im_session_from_storage,
     build_cookie_credential_detail,
+    credential_egress_mismatch,
 )
 from utils.cookie_store import (
     write_cookie_file,
@@ -1864,6 +1865,7 @@ async def update_account(
     if body.user_agent is not None:
         ua = (body.user_agent or "").strip()
         account.user_agent = ua or None
+    egress_changed = False
     if "egress_public_ip" in body.model_fields_set:
         selected_public_ip = str(body.egress_public_ip or "").strip()
         if selected_public_ip:
@@ -1873,12 +1875,27 @@ async def update_account(
                 raise HTTPException(status_code=400, detail="公网通道必须是有效的 IPv4 地址")
             if parsed_ip.version != 4:
                 raise HTTPException(status_code=400, detail="公网通道目前仅支持 IPv4")
+        previous_public_ip = str(account.egress_public_ip or "").strip()
+        egress_changed = previous_public_ip != selected_public_ip
         account.egress_public_ip = selected_public_ip or None
     if body.egress_auto_attempts is not None:
         account.egress_auto_attempts = clamp_attempts(body.egress_auto_attempts)
     account.updated_at = datetime.utcnow()
     await db.commit()
     await db.refresh(account)
+    if egress_changed and manager.is_running(account_id):
+        await manager.stop_worker(account_id)
+        await db.execute(
+            update(Account).where(Account.id == account_id).values(
+                status="offline",
+                error_message=(
+                    "公网通道已变更，请重新启动托管以使用新通道；"
+                    "已保留登录凭证，校验通过后无需重新扫码"
+                ),
+            )
+        )
+        await db.commit()
+        await db.refresh(account)
     if follow_config_changed:
         worker = manager.workers.get(account_id)
         invalidate = getattr(worker, "invalidate_follow_welcome_config", None)
@@ -1888,8 +1905,9 @@ async def update_account(
     runtime_service = getattr(worker, "_im_service", None) if worker else None
     if runtime_service:
         runtime_session = runtime_service.session
-        runtime_session.egress_public_ip = str(account.egress_public_ip or "").strip()
-        runtime_session.egress_source_ip = ""
+        # Reconnect after a public-IP change so HTTP and the existing WS do
+        # not use different routes.  Reconnecting does not invalidate cookies.
+        # Only the retry-count can be hot-updated without reconnecting.
         runtime_session.egress_auto_attempts = clamp_attempts(account.egress_auto_attempts)
     return _build_account_response(account)
 
@@ -2350,13 +2368,26 @@ async def _start_account_rpa_impl(
     # Credential assessment issues real network requests to Douyin, and a bulk
     # start runs it for every queued account.  Release the connection first.
     await _release_db_connection(db)
+    reset_performed = False
+
+    selected_public_ip = str(getattr(account, "egress_public_ip", "") or "").strip()
+    if credential_egress_mismatch(cookie_data, selected_public_ip):
+        # The stored IP is local metadata, not a platform authentication
+        # verdict.  Imported/legacy cookies may not have it at all.  Keep the
+        # credentials and use normal validation on the selected route.
+        logger.info(
+            "Account %s egress marker differs; preserving credentials and "
+            "validating on selected channel %s",
+            account_id,
+            selected_public_ip or "default",
+        )
     assessment = await assess_account_credential(
         cookie_data,
         account.im_session_data,
         startup_priority=True,
+        egress_public_ip=selected_public_ip,
     )
     login_mode = requested_login_mode or assessment["login_mode"]
-    reset_performed = False
 
     if assessment.get("should_reset") and login_mode != "im_direct":
         account = await _reset_account_credentials(account_id, db)

backend/rpa_engine/credential.py

@@ -10,6 +10,33 @@ from utils.cookie_store import analyze_cookie
 
 logger = logging.getLogger("credential")
 
+CREDENTIAL_EGRESS_PUBLIC_IP_KEY = "credential_egress_public_ip"
+
+
+def credential_egress_mismatch(
+    cookie_data: Optional[str],
+    selected_public_ip: str = "",
+) -> bool:
+    """Compare historical browser egress metadata for diagnostics only.
+
+    This is not an authentication check: a different or missing local marker
+    cannot prove that cookies are invalid.  Callers must keep the credentials
+    and use normal validation instead of forcing a reset or browser login.
+    """
+    if not cookie_data:
+        return False
+    try:
+        storage = json.loads(cookie_data)
+    except (TypeError, ValueError):
+        return False
+    if not isinstance(storage, dict):
+        return False
+    selected = str(selected_public_ip or "").strip()
+    if CREDENTIAL_EGRESS_PUBLIC_IP_KEY not in storage:
+        return bool(selected)
+    stored = str(storage.get(CREDENTIAL_EGRESS_PUBLIC_IP_KEY) or "").strip()
+    return stored != selected
+
 
 def _should_reset_credentials(assessment: dict) -> bool:
     """凭证全面失效时需清空 Cookie/IM 数据并重新登录。"""
@@ -202,6 +229,7 @@ async def assess_account_credential(
     im_session_data: Optional[str] = None,
     *,
     startup_priority: bool = False,
+    egress_public_ip: str = "",
 ) -> dict:
     cookie_info = analyze_cookie(cookie_data)
     result = {
@@ -227,6 +255,18 @@ async def assess_account_credential(
         return result
 
     session = build_im_session_from_storage(storage, im_session_data)
+    selected_public_ip = str(egress_public_ip or "").strip()
+    if selected_public_ip:
+        try:
+            from rpa_engine.egress_channels import resolve_fixed_channel
+
+            route = await resolve_fixed_channel(selected_public_ip)
+            session.egress_public_ip = selected_public_ip
+            session.egress_source_ip = str(route.source_ip or "")
+        except Exception as exc:
+            result["message"] = f"指定公网通道 {selected_public_ip} 当前不可用：{exc}"
+            result["login_mode"] = "browser"
+            return result
     result["has_sessionid"] = has_im_session_token(session)
 
     if not cookie_info.get("cookie_valid"):

backend/rpa_engine/douyin_im/auth.py

@@ -129,6 +129,7 @@ class DouyinAuth:
         auth.device_id = resolve_proto_device_id(
             session.device_id, session.web_id, session.my_uid
         )
+        auth.source_ip = str(getattr(session, "egress_source_ip", "") or "")
         # web_protect 缺 client_cert 时，才用 frontier 抓包证书兜底（不覆盖 ts_sign）
         if not auth.client_cert and getattr(session, "sdk_cert", ""):
             auth.client_cert = normalize_client_cert(session.sdk_cert)

backend/rpa_engine/douyin_im/conv_util.py

@@ -45,3 +45,26 @@ def normalize_conversation_id(conversation_id: str, my_uid: int) -> str:
     if peer_uid and my_uid:
         return build_conversation_id(my_uid, peer_uid)
     return (conversation_id or "").strip()
+
+
+def conversation_belongs_to(conversation_id: str, my_uid: int) -> bool:
+    """判断单聊会话是否属于 my_uid 本人。
+
+    托管多个账号时，一条属于别的账号的会话（例如 frontier 长连接按设备号寻址
+    造成的跨账号推送）一旦流进本账号的处理链路，resolve_peer_uid 会把末段当成
+    「对方」、normalize_conversation_id 再拼成 0:1:{本账号}:{别人的好友}，于是
+    本账号就把消息发给了另一个账号的好友。这里给出唯一的归属判据。
+
+    无法判定时一律返回 True（保守放行）：缺 my_uid、群聊、裸 UID 等形态本来就
+    不带参与方信息。只有两个参与方都已知、且都不是本账号时才判定为不属于本账号。
+    """
+    try:
+        uid = int(my_uid or 0)
+    except (TypeError, ValueError):
+        return True
+    if not uid:
+        return True
+    parts = parse_conversation_parts(conversation_id)
+    if not parts:
+        return True
+    return uid in parts

backend/rpa_engine/douyin_im/frontier.py

@@ -102,11 +102,16 @@ def resolve_frontier_device_id(session: DouyinImSession) -> str:
     return ""
 
 
-def _ws_device_id(url: str) -> str:
+def ws_device_id(url: str) -> str:
+    """frontier 推送的寻址键：设备号（不是账号 UID）。"""
     m = re.search(r"[?&]device_id=([^&\s]+)", url or "")
     return unquote(m.group(1)) if m else ""
 
 
+# 兼容内部旧引用
+_ws_device_id = ws_device_id
+
+
 def _ws_device_matches_session(session: DouyinImSession, url: str) -> bool:
     ws_dev = _ws_device_id(url)
     if not ws_dev or not ws_dev.isdigit():

backend/rpa_engine/douyin_im/http_client.py

@@ -14,7 +14,12 @@ from rpa_engine.egress_channels import (
     resolve_fixed_channel,
     resolve_send_channels,
 )
-from .conv_util import build_conversation_id, normalize_conversation_id, resolve_peer_uid
+from .conv_util import (
+    build_conversation_id,
+    conversation_belongs_to,
+    normalize_conversation_id,
+    resolve_peer_uid,
+)
 from .message_content import format_im_message, serialize_message_content
 from .peer_profile import enrich_conversation_item, fetch_peer_profile, is_generic_peer_name
 from .protocol import normalize_im_payload_from_bytes, _pick_avatar_url
@@ -1144,8 +1149,17 @@ class DouyinImHttpClient:
             self.session.my_uid,
             uid,
         )
+        previous = int(self.session.my_uid or 0)
         self.session.my_uid = uid
         self.session.uid_verified = True
+        # 托管注册表按 UID 记录「本系统正在托管谁」。纠正后必须迁移，否则回环
+        # 防护会认错人：旧 UID 永远留在表里，真实 UID 从未登记。只迁移确实已登记
+        # 的托管身份，避免 API 侧的临时客户端把自己也登记进去。
+        from . import hosted_registry
+
+        if hosted_registry.is_hosted(previous):
+            hosted_registry.unregister(previous)
+            hosted_registry.register(uid)
 
     async def get_conversations(
         self,
@@ -1383,6 +1397,26 @@ class DouyinImHttpClient:
             self._set_error("无法获取当前账号 UID")
             self._log_send_failure(conversation_id, "无法获取当前账号 UID（Cookie 可能已失效）")
             return False
+
+        # 跨账号写入闸门：normalize_conversation_id 会把任何会话 ID 改写成
+        # 0:1:{本账号}:{末段 UID}，所以一条属于别的账号的会话流到这里会被
+        # 静默改写并发给对方的好友。发送前先确认本账号确实是该会话的参与方。
+        if not conversation_belongs_to(conversation_id, my_uid):
+            detail = (
+                f"会话 {conversation_id} 的参与方都不是本账号（uid={my_uid}），"
+                "拒绝发送：这条会话属于另一个账号，继续发送会把消息发给别人的好友。"
+            )
+            self._set_error(detail)
+            self.last_send_channel_retryable = False
+            self._log_send_failure(conversation_id, detail)
+            logger.error(
+                "Account %s refused cross-account send to %s (my_uid=%s)",
+                self.account_id,
+                conversation_id,
+                my_uid,
+            )
+            return False
+
         if not auth.is_sign_ready():
             self._set_error("缺少 IM 签名密钥，请用浏览器登录补全 localStorage")
             self._log_send_failure(
@@ -1510,10 +1544,14 @@ class DouyinImHttpClient:
             decision = str(result.get("decision") or "").strip().upper()
 
             if decision == "KICK":
-                self.last_send_channel_retryable = True
+                # KICK is a terminal, account-session decision.  Retrying the
+                # same authenticated write from another source address cannot
+                # repair the session and only adds another high-risk request.
+                self.last_send_needs_refresh = False
+                self.last_send_channel_retryable = False
                 detail = (
                     "抖音安全网关返回 decision=KICK，当前登录/安全会话已被服务端踢下线；"
-                    "系统正在自动重登录，请留意账号卡片上的二维码并扫码"
+                    "已停止本次发送及公网通道重试，系统正在自动重登录，请留意账号卡片上的二维码并扫码"
                 )
             elif decision:
                 detail = f"抖音安全网关拒绝发送 decision={decision}"
@@ -1527,7 +1565,11 @@ class DouyinImHttpClient:
                     hint = _BUSINESS_REJECT_FALLBACK
                 # 7911 属于“签名凭证失效/安全校验未过”，标记为可刷新后重试
                 self.last_send_needs_refresh = status_code in _CREDENTIAL_EXPIRED_CODES
-                self.last_send_channel_retryable = self.last_send_needs_refresh
+                # 7911 is a credential/signature problem.  It may be retried
+                # once only after refreshing the credentials on the same
+                # session; switching egress mid-session makes the fingerprint
+                # less consistent and must not be used as the recovery path.
+                self.last_send_channel_retryable = False
                 detail = f"抖音拒绝投递 status_code={status_code}"
                 if status_reason:
                     detail += f"；抖音提示：{status_reason}"
@@ -1550,7 +1592,10 @@ class DouyinImHttpClient:
                 detail = "；".join(reason_bits) or "接口返回但未确认投递（无 server_message_id）"
 
             if "INVALID_REQUEST" in detail.upper():
-                self.last_send_channel_retryable = True
+                # INVALID_REQUEST is a protocol/session rejection, not a
+                # transport failure.  A second public IP sends the same invalid
+                # request and can invalidate an otherwise recoverable login.
+                self.last_send_channel_retryable = False
             full_detail = f"{detail}；{target}；resp[{result.get('summary')}]"
             if self.last_request_debug:
                 full_detail += f"\n--- 请求详情 ---\n{self.last_request_debug}"

backend/rpa_engine/douyin_im/service.py

@@ -17,7 +17,8 @@ from .reply_queue import AccountReplyQueue
 from .traffic_control import get_traffic_controller
 
 from .reply_payload import format_reply_display, serialize_reply_log
-from .conv_util import resolve_peer_uid
+from . import hosted_registry
+from .conv_util import conversation_belongs_to, resolve_peer_uid
 from .peer_profile import (
     enrich_conversation_item,
     fetch_peer_profile,
@@ -338,6 +339,10 @@ class DouyinImService:
         self._ready_notified = False
         self._session_invalid_strikes = 0
         self._session_invalid_fired = False
+        # A keepalive browser may refresh cookies/security material while an
+        # outbound reply is being prepared.  Serialize the short credential
+        # hand-off with sends so one request never mixes old and new state.
+        self._session_lock = asyncio.Lock()
         self.reply_delay_seconds = max(0, int(reply_delay_seconds or 0))
         # 实时解析账号排队间隔：账号专属优先，否则使用系统默认值。
         self._reply_delay_resolver = reply_delay_resolver
@@ -355,15 +360,19 @@ class DouyinImService:
         self._cooldown_resolver = cooldown_resolver
         # 由 worker 注入：触发后台重新采集 web_protect/keys（刷新 ts_sign），返回是否刷新成功
         self.refresh_credentials = refresh_credentials
-        # 由 worker 注入的第二套发送方案：当 HTTP 签名发送被安全网关拒绝
-        # （decision=KICK / 7911 / INVALID_REQUEST）时，用浏览器页面上下文
-        # 重新发送（真实 JS 生成 a_bogus/bd-ticket-guard，可自愈被踢的会话）。
+        # 由 worker 注入的第二套发送方案：仅当 HTTP 返回非终态的 7911
+        # 签名错误时，可在同一账号/同一出口的浏览器页面上下文重试一次。
+        # KICK 与 INVALID_REQUEST 不得重放，避免在已失效会话上继续写请求。
         # 签名: async (conversation_id, content) -> (ok, detail)
         self.send_fallback = send_fallback
         self._running = False
         self._replied_keys: set[str] = set()
         self._logged_keys: set[str] = set()
         self._received_logged_keys: set[str] = set()
+        # 已告警过的「不属于本账号」的会话，避免同一条串号会话刷屏
+        self._foreign_conv_logged: set[str] = set()
+        # 已告警过的「对方也是本系统托管账号」的 peer，避免同一对账号刷屏
+        self._hosted_peer_logged: set[str] = set()
         # 每个对话/用户最近一次自动回复的时间戳（monotonic 秒），用于冷却窗口去重
         self._last_reply_at: dict[str, float] = {}
         self._conv_previews: dict[str, str] = {}
@@ -510,6 +519,38 @@ class DouyinImService:
             return f"用户{sender_uid[-6:]}" if len(sender_uid) > 6 else f"用户{sender_uid}"
         return "未知用户"
 
+    def _conversation_is_mine(self, conv_id: str) -> bool:
+        """本账号是否为该单聊会话的参与方；不是就丢弃，绝不改写后发送。"""
+        my_uid = int(self.session.my_uid or 0)
+        if conversation_belongs_to(conv_id, my_uid):
+            return True
+        conv_key = str(conv_id or "")
+        logger.warning(
+            "Account %s dropped a message from foreign conversation %s "
+            "(my_uid=%s); two accounts most likely share one set of credentials",
+            self.account_id,
+            conv_key,
+            my_uid,
+        )
+        if conv_key not in self._foreign_conv_logged:
+            if len(self._foreign_conv_logged) > 200:
+                self._foreign_conv_logged.clear()
+            self._foreign_conv_logged.add(conv_key)
+            system_logger.record(
+                "已丢弃不属于本账号的私信",
+                detail=(
+                    f"会话 {conv_key} 的参与方都不是本账号（uid={my_uid}），"
+                    "该消息属于另一个账号，已丢弃且不会自动回复。"
+                    "常见原因：多个账号的凭证来自同一台机器/同一个浏览器，"
+                    "frontier 长连接按设备号寻址导致两个账号互相收到对方的私信。"
+                    "请为每个账号单独采集凭证（独立浏览器配置/设备）。"
+                ),
+                level="warning",
+                category="recv",
+                account_id=self.account_id,
+            )
+        return False
+
     def _is_self_message(self, msg: dict) -> bool:
         sender_uid = str(msg.get("sender_uid") or "").strip()
         if not sender_uid or not self.session.my_uid:
@@ -637,10 +678,18 @@ class DouyinImService:
         self,
         msg: dict,
     ) -> Optional[Callable[[], Awaitable[None]]]:
+        conv_id = msg.get("conversation_id") or ""
+        # 跨账号隔离：只处理本账号自己的会话。frontier 按设备号寻址推送，
+        # 同一台机器/同一浏览器采集出来的多个账号 device_id 可能相同，两条长连接
+        # 会订阅到同一个地址并互相收到对方的私信。若不在这里拦住，
+        # normalize_conversation_id 会把别人的会话改写成
+        # 0:1:{本账号}:{别人的好友}，本账号就把自动回复发给了另一个账号的好友。
+        if not self._conversation_is_mine(conv_id):
+            return
+
         if self._is_self_message(msg):
             return
 
-        conv_id = msg.get("conversation_id") or ""
         sender_uid = str(msg.get("sender_uid") or "")
         sender = self._resolve_sender_name(msg)
         sender_avatar = str(msg.get("sender_avatar") or "").strip()
@@ -769,6 +818,44 @@ class DouyinImService:
         # 防止延迟排队期间被重复加入发送队列。
         self._replied_keys.add(key)
 
+        # 对方也是本系统托管的账号：双方都会自动回复，一来一回就是无限回环。
+        # 这种高频互发是触发抖音风控(7911)/业务拒绝(8004)的常见根因，因此消息
+        # 照常记录，但不再自动回复。需要回复请用消息页手动发送。
+        if peer_uid and hosted_registry.is_hosted(peer_uid):
+            await self.log_fn(
+                **log_kwargs,
+                reply=None,
+                status="ignored",
+                error=(
+                    f"对方（UID {peer_uid}）也是本系统托管中的账号，"
+                    "自动回复会在两个账号之间形成无限回环并触发抖音风控，已跳过；"
+                    "如需回复请在消息页手动发送"
+                ),
+            )
+            if content:
+                self._conv_previews[sender] = content
+            if peer_uid not in self._hosted_peer_logged:
+                if len(self._hosted_peer_logged) > 200:
+                    self._hosted_peer_logged.clear()
+                self._hosted_peer_logged.add(peer_uid)
+                logger.info(
+                    "Account %s skipped auto-reply to hosted account %s",
+                    self.account_id,
+                    peer_uid,
+                )
+                system_logger.record(
+                    "自动回复已跳过（对方也是托管账号）",
+                    detail=(
+                        f"{sender}（UID {peer_uid}）是本系统托管中的另一个账号。"
+                        "两个托管账号互相自动回复会形成无限回环，"
+                        "属于抖音风控(7911/8004)的高发场景，因此只记录消息、不自动回复。"
+                    ),
+                    level="warning",
+                    category="send",
+                    account_id=self.account_id,
+                )
+            return
+
         # 同账号、同会话只保留一个尚未发送的回复任务。后续来信只追加到
         # 原任务详情，不改变它的发送时间、位置或已经匹配好的回复。
         queue_merge_keys = self._reply_queue_merge_keys(conv_id, peer_uid)
@@ -1428,11 +1515,60 @@ class DouyinImService:
         """把指定自动回复任务移入账号紧急队列；实际发送仍由单消费者串行执行。"""
         return await self._reply_queue.send_now(job_id)
 
+    async def replace_session(self, fresh: DouyinImSession) -> None:
+        """Atomically install a freshly harvested login/security session.
+
+        The running WebSocket can keep its current connection, but future
+        reconnects and every HTTP send must see the same refreshed object.
+        Account egress selection lives outside persisted IM credentials, so it
+        is deliberately carried over from the current runtime session.
+        """
+        async with self._session_lock:
+            current = self.session
+            current_uid = int(getattr(current, "my_uid", 0) or 0)
+            fresh_uid = int(getattr(fresh, "my_uid", 0) or 0)
+            if current_uid and fresh_uid and current_uid != fresh_uid:
+                raise ValueError(
+                    f"refusing cross-account session refresh: {current_uid} != {fresh_uid}"
+                )
+
+            fresh.conv_meta = {
+                **dict(getattr(current, "conv_meta", {}) or {}),
+                **dict(getattr(fresh, "conv_meta", {}) or {}),
+            }
+            if not fresh.ws_urls:
+                fresh.ws_urls = list(getattr(current, "ws_urls", []) or [])
+            fresh.egress_public_ip = str(
+                getattr(current, "egress_public_ip", "") or ""
+            )
+            fresh.egress_source_ip = str(
+                getattr(current, "egress_source_ip", "") or ""
+            )
+            fresh.egress_auto_attempts = int(
+                getattr(current, "egress_auto_attempts", 1) or 1
+            )
+            self.session = fresh
+            if self._ws_client is not None:
+                self._ws_client.session = fresh
+
     async def _send_text(
         self,
         conversation_id: str,
         content: str,
         conversation_short_id: str = "",
+    ) -> tuple[bool, Optional[dict]]:
+        async with self._session_lock:
+            return await self._send_text_unlocked(
+                conversation_id,
+                content,
+                conversation_short_id=conversation_short_id,
+            )
+
+    async def _send_text_unlocked(
+        self,
+        conversation_id: str,
+        content: str,
+        conversation_short_id: str = "",
     ) -> tuple[bool, Optional[dict]]:
         """发送一条私信；若因签名凭证失效(7911)失败，刷新 web_protect 后自动重试一次。
 
@@ -1468,16 +1604,14 @@ class DouyinImService:
                     continue
             break
 
-        # 第二套发送方案（浏览器页面内发送）：
-        # HTTP 签名发送被安全网关拒绝（KICK/7911/INVALID_REQUEST）时，交给 worker
-        # 用浏览器页面上下文重发——由抖音页面自带的 security-sdk 在真实环境生成
-        # a_bogus/bd-ticket-guard，绕开我们 Node execjs 的签名模拟，可自愈被踢会话。
+        # 第二套发送方案（浏览器页面内发送）：仅处理非终态 7911。
+        # KICK/INVALID_REQUEST 会停止发送并进入下线处理，不在失效会话上重放。
         upper_err = (self.last_error or "").upper()
-        if self.send_fallback and (
-            "DECISION=KICK" in upper_err
-            or "STATUS_CODE=7911" in upper_err
-            or "INVALID_REQUEST" in upper_err
-        ):
+        # KICK already invalidated the login and INVALID_REQUEST is a
+        # protocol/session rejection.  Replaying either through a browser
+        # fetch cannot heal it and creates another risky write.  7911 is the
+        # only non-terminal signing failure eligible for the browser fallback.
+        if self.send_fallback and "STATUS_CODE=7911" in upper_err:
             try:
                 fb_ok, fb_detail = await self.send_fallback(conversation_id, content)
             except Exception as exc:

backend/rpa_engine/douyin_im/ws_client.py

@@ -103,6 +103,12 @@ _LOOP_STATES: "weakref.WeakKeyDictionary[asyncio.AbstractEventLoop, _LoopWsState
 )
 
 
+# frontier 按 device_id 寻址推送：两个托管账号共用同一个设备号时，两条长连接会
+# 订阅到同一个地址并互相收到对方的私信。真正的拦截在 service 的会话归属校验里，
+# 这里只负责把「为什么会串号」明确告诉用户。持弱引用，账号停管后自动失效。
+_FRONTIER_DEVICE_OWNERS: "dict[str, weakref.ref[DouyinImWsClient]]" = {}
+
+
 def _get_loop_state() -> _LoopWsState:
     loop = asyncio.get_running_loop()
     state = _LOOP_STATES.get(loop)
@@ -155,6 +161,8 @@ class DouyinImWsClient:
         self._dispatcher_task: Optional[asyncio.Task] = None
         self._received_frame_count = 0
         self._heartbeat_ack_logged = False
+        self._frontier_device_id = ""
+        self._blocked_device_owner_id: Optional[int] = None
 
     async def start(self):
         if self._task and not self._task.done():
@@ -210,6 +218,7 @@ class DouyinImWsClient:
         if self._task is task:
             self._task = None
         self._connection = None
+        self._release_frontier_device()
         await self._stop_dispatcher()
 
     def _record_connection_system_event(
@@ -247,6 +256,7 @@ class DouyinImWsClient:
         account_key = int(self.account_id or 0)
         state.system_log_last_at.pop((account_key, "connected"), None)
         state.system_log_last_at.pop((account_key, "retry"), None)
+        state.system_log_last_at.pop((account_key, "device_taken"), None)
 
     def _ensure_dispatcher(self) -> None:
         if self._dispatcher_task and not self._dispatcher_task.done():
@@ -311,8 +321,15 @@ class DouyinImWsClient:
                 first_attempt = False
                 if not connect_url:
                     raise RuntimeError("frontier WebSocket URL is unavailable")
-                logger.info("Connecting IM WebSocket: %s...", connect_url[:100])
-                await self._run_connection(connect_url)
+                if self._claim_frontier_device(connect_url):
+                    logger.info("Connecting IM WebSocket: %s...", connect_url[:100])
+                    await self._run_connection(connect_url)
+                else:
+                    # 设备号已被另一个在跑的账号占用：绝不并连同一个推送地址，
+                    # 本账号本轮退回 HTTP 轮询兜底（connected 保持 False，
+                    # service 会自动切到更快的会话对账节奏），并在退避后重试，
+                    # 等占用方停管时自动接管。
+                    self._report_frontier_device_taken(connect_url)
             except asyncio.CancelledError:
                 break
             except Exception as exc:
@@ -348,6 +365,76 @@ class DouyinImWsClient:
             except asyncio.CancelledError:
                 break
 
+        self._release_frontier_device()
+
+    def _frontier_device_owner(self, device_id: str) -> "Optional[DouyinImWsClient]":
+        """当前仍活着的设备号占用方（run 循环任务还在跑才算数）。"""
+        reference = _FRONTIER_DEVICE_OWNERS.get(device_id)
+        owner = reference() if reference is not None else None
+        if owner is None or owner is self:
+            return None
+        task = owner._task
+        if not owner._running or task is None or task.done():
+            return None
+        return owner
+
+    def _claim_frontier_device(self, url: str) -> bool:
+        """独占本账号的 frontier 设备地址；已被别的账号占用时返回 False。
+
+        frontier 按 device_id 寻址推送。两个账号共用同一个设备号时，同时建连
+        会让两条连接互相收到对方的私信（串号的根因），且抖音也可能只保留最后
+        一条连接、把先连上的那个账号踢成「连着但收不到」。所以同一个设备地址
+        永远只允许一个账号建连，另一个账号走 HTTP 轮询兜底。
+        """
+        from .frontier import ws_device_id
+
+        device_id = ws_device_id(url)
+        if not device_id:
+            # 判不出设备号（自建地址/异常格式）时不阻断连接，交给会话归属校验兜底。
+            return True
+        owner = self._frontier_device_owner(device_id)
+        if owner is not None and int(owner.account_id or 0) != int(self.account_id or 0):
+            self._blocked_device_owner_id = owner.account_id
+            return False
+        _FRONTIER_DEVICE_OWNERS[device_id] = weakref.ref(self)
+        self._frontier_device_id = device_id
+        self._blocked_device_owner_id = None
+        return True
+
+    def _report_frontier_device_taken(self, url: str) -> None:
+        from .frontier import ws_device_id
+
+        device_id = ws_device_id(url)
+        owner_id = self._blocked_device_owner_id
+        logger.error(
+            "Account %s cannot open frontier device_id %s: already held by "
+            "account %s; falling back to HTTP polling this round",
+            self.account_id,
+            device_id,
+            owner_id,
+        )
+        self._record_connection_system_event(
+            "device_taken",
+            "实时接收已让出：与另一个账号共用长连接设备号",
+            detail=(
+                f"本账号与账号 {owner_id} 的 frontier 设备号相同（device_id={device_id}）。"
+                "同一个设备地址只允许一个账号建立长连接，否则两个账号会互相收到对方的"
+                "私信。本账号本轮不建连，改由 HTTP 会话轮询接收（有几十秒级延迟），"
+                "并在对方停止托管后自动接管。"
+                "根治办法：为每个账号在独立的浏览器配置/设备上重新采集凭证。"
+            ),
+            level="error",
+        )
+
+    def _release_frontier_device(self) -> None:
+        device_id = self._frontier_device_id
+        self._frontier_device_id = ""
+        if not device_id:
+            return
+        reference = _FRONTIER_DEVICE_OWNERS.get(device_id)
+        if reference is not None and reference() is self:
+            _FRONTIER_DEVICE_OWNERS.pop(device_id, None)
+
     def _connection_headers(self) -> list[tuple[str, str]]:
         headers = [
             ("Pragma", "no-cache"),

backend/rpa_engine/playwright_worker.py

@@ -28,7 +28,11 @@ from rpa_engine.douyin_im.session import DouyinImSession
 from rpa_engine.douyin_im.frontier import ensure_frontier_ws
 from rpa_engine.douyin_im.http_client import DouyinImHttpClient
 from rpa_engine.douyin_im.traffic_control import get_traffic_controller
-from rpa_engine.credential import validate_im_session, build_im_session_from_storage
+from rpa_engine.credential import (
+    CREDENTIAL_EGRESS_PUBLIC_IP_KEY,
+    validate_im_session,
+    build_im_session_from_storage,
+)
 from rpa_engine.device_profiles import resolve_user_agent
 from rpa_engine.runtime_config import (
     resolve_headless,
@@ -36,6 +40,7 @@ from rpa_engine.runtime_config import (
     playwright_proxy,
 )
 from rpa_engine.egress_channels import clamp_attempts, resolve_fixed_channel
+from rpa_engine.source_bound_proxy import playwright_proxy_for_source
 
 logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
 logger = logging.getLogger("rpa_engine")
@@ -55,7 +60,12 @@ async def _start_playwright_for_browser(headless: Optional[bool] = None):
     return await async_playwright().start(), headless
 
 
-async def _launch_chromium(pw, args: list[str], headless: Optional[bool] = None):
+async def _launch_chromium(
+    pw,
+    args: list[str],
+    headless: Optional[bool] = None,
+    source_ip: str = "",
+):
     """统一的 Chromium 启动入口：自动处理无头/有头、虚拟显示与住宅代理。
 
     - headless 默认由 KEFU_BROWSER_HEADLESS 决定（缺省有头，避免抖音安全 SDK 判定）。
@@ -66,10 +76,21 @@ async def _launch_chromium(pw, args: list[str], headless: Optional[bool] = None)
         headless = resolve_headless(default=False)
     await ensure_browser_display(headless)
     launch_kwargs: dict = {"headless": headless, "args": args}
-    proxy = playwright_proxy()
+    proxy = (
+        await playwright_proxy_for_source(source_ip)
+        if source_ip
+        else playwright_proxy()
+    )
     if proxy:
         launch_kwargs["proxy"] = proxy
-        logger.info("浏览器将通过代理启动：%s", proxy.get("server"))
+        if source_ip:
+            logger.info(
+                "浏览器将固定使用本机源地址 %s（本地代理 %s）",
+                source_ip,
+                proxy.get("server"),
+            )
+        else:
+            logger.info("浏览器将通过代理启动：%s", proxy.get("server"))
     return await pw.chromium.launch(**launch_kwargs)
 
 
@@ -223,6 +244,44 @@ class DouyinWorker:
     async def get_db(self):
         return AsyncSessionLocal()
 
+    async def _resolve_browser_source_ip(self) -> str:
+        """Resolve the account's fixed browser egress source address.
+
+        Browser login, keepalive and credential refresh must use the same
+        public channel as IM HTTP/WS.  Silently falling back to the default
+        route for a selected-but-unavailable channel would create a mixed-IP
+        security session, so that case intentionally fails closed.
+        """
+        selected = await self._load_selected_egress_public_ip()
+        if not selected:
+            return ""
+        route = await resolve_fixed_channel(selected)
+        source_ip = str(route.source_ip or "").strip()
+        if not source_ip:
+            raise RuntimeError(
+                f"账号指定公网通道 {selected} 无法绑定到本机网卡，已停止浏览器登录/刷新，"
+                "避免登录出口与发送出口不一致"
+            )
+        return source_ip
+
+    async def _load_selected_egress_public_ip(self) -> str:
+        db = await self.get_db()
+        try:
+            result = await db.execute(
+                select(Account.egress_public_ip).where(Account.id == self.account_id)
+            )
+            selected = str(result.scalar_one_or_none() or "").strip()
+        except Exception as exc:
+            logger.debug(
+                "Account %s browser egress config unavailable: %s",
+                self.account_id,
+                exc,
+            )
+            return ""
+        finally:
+            await db.close()
+        return selected
+
     def _mark_startup_ready(self) -> None:
         self._startup_error = ""
         self._startup_ready.set()
@@ -640,6 +699,7 @@ class DouyinWorker:
                 "--no-sandbox",
                 "--disable-setuid-sandbox",
             ],
+            source_ip=await self._resolve_browser_source_ip(),
         )
         if storage_state:
             self.context = await self.browser.new_context(
@@ -679,10 +739,13 @@ class DouyinWorker:
     async def _persist_cookies(self):
         """登录成功或运行中将 Cookie 同步到文件和数据库（合并 HttpOnly sessionid）"""
         if not self.context:
-            return
+            return None
         storage = await self.context.storage_state()
         live_cookies = await self.context.cookies()
         storage = merge_playwright_cookies(storage, live_cookies)
+        storage[CREDENTIAL_EGRESS_PUBLIC_IP_KEY] = (
+            await self._load_selected_egress_public_ip()
+        )
         cookie_json = json.dumps(storage, ensure_ascii=False, indent=2)
         with open(self.cookie_path, "w", encoding="utf-8") as f:
             f.write(cookie_json)
@@ -704,6 +767,7 @@ class DouyinWorker:
             await db.rollback()
         finally:
             await db.close()
+        return storage
 
     async def _build_im_session_from_storage(
         self,
@@ -1172,8 +1236,8 @@ class DouyinWorker:
             # 不在发送链路上自动开浏览器刷新：实测重载页面并不会重生 web_protect，
             # 反而每次失败阻塞 ~22s（"反应特别慢"），且无法解决 7911 风控。
             refresh_credentials=None,
-            # 第二套发送方案：HTTP 签名发送被 KICK/7911/INVALID_REQUEST 拒绝时，
-            # 用浏览器页面上下文重发（真实 JS 签名，可自愈被踢会话）。
+            # 第二套发送方案：仅在非终态 7911 时用同出口浏览器页面重试；
+            # KICK/INVALID_REQUEST 必须停发并下线，不能继续重放。
             send_fallback=self.send_im_via_browser_page,
         )
         self._im_service = im_service
@@ -1332,7 +1396,10 @@ class DouyinWorker:
                     if sys.platform == "win32":
                         args.append("--start-minimized")
                     browser = await _launch_chromium(
-                        pw, args, headless=browser_headless
+                        pw,
+                        args,
+                        headless=browser_headless,
+                        source_ip=await self._resolve_browser_source_ip(),
                     )
                     ua = self._user_agent or resolve_user_agent(None)
                     context = await browser.new_context(
@@ -1397,13 +1464,26 @@ class DouyinWorker:
                             f"after[{self._fmt_expires_map(after_exp)}] "
                             f"renewed={','.join(renewed) or 'none'}"
                         )
-                    # 活跃访问后 cookie（msToken 等）可能更新，重新落库
+                    # 活跃访问后 cookie（msToken 等）可能更新。Cookie、ticket、
+                    # ts_sign、private key 是一套安全会话，不能只更新数据库里的
+                    # cookie 而让正在发送的内存会话继续使用旧值；否则 WS 仍能收，
+                    # 下一次写请求却会因新旧凭证混用被安全网关 KICK。
                     try:
                         await self._persist_cookies()
+                        service = self._im_service
+                        if service is not None:
+                            fresh_session = await self._build_im_session()
+                            await service.replace_session(fresh_session)
+                            await self._persist_im_session(service.session)
+                            logger.info(
+                                "Account %s: keepalive credentials synchronized "
+                                "to active IM session",
+                                self.account_id,
+                            )
                     except Exception as exc:
                         logger.warning(
-                            f"Account {self.account_id}: keepalive persist cookies "
-                            f"failed: {exc}"
+                            f"Account {self.account_id}: keepalive credential sync "
+                            f"failed; active session left unchanged: {exc}"
                         )
                     return True, f"已访问 {target_url} 并刷新登录态"
                 except asyncio.CancelledError:
@@ -1445,16 +1525,19 @@ class DouyinWorker:
     ) -> tuple[bool, str]:
         """第二套发送方案：浏览器页面上下文内重发私信。
 
-        HTTP 签名发送被抖音安全网关拒绝（decision=KICK / 7911 / INVALID_REQUEST）
-        时的兜底：用已保存的登录态打开抖音页面，由页面自带 security-sdk 在真实
-        浏览器环境里生成 a_bogus / bd-ticket-guard 并完成发送——绕开 Node execjs
-        的签名模拟；浏览器重新加载页面也会重建安全会话，可自愈被服务端踢掉的
-        登录态。仅文本/表情/卡片内容可用，图片需先走 HTTP 上传链路。
+        仅供非终态 7911 签名错误使用：用已保存的登录态打开抖音页面，在与账号
+        相同的固定出口中完成一次页面内发送。KICK/INVALID_REQUEST 不会调用此
+        方法，避免对已经失效的登录态继续重放。仅文本/表情/卡片内容可用，图片
+        需先走 HTTP 上传链路。
 
         返回 (是否成功, 详情)。失败不会抛异常，只记录日志。
         """
         from rpa_engine.douyin_im.auth import DouyinAuth
-        from rpa_engine.douyin_im.conv_util import normalize_conversation_id, resolve_peer_uid
+        from rpa_engine.douyin_im.conv_util import (
+            conversation_belongs_to,
+            normalize_conversation_id,
+            resolve_peer_uid,
+        )
         from rpa_engine.douyin_im.pb_decode import analyze_send_response
         from rpa_engine.douyin_im.proto_builder import ProtoBuilder
         from rpa_engine.douyin_im.reply_payload import build_msg_payload, parse_reply_content
@@ -1476,6 +1559,13 @@ class DouyinWorker:
             if not my_uid:
                 return False, "无法获取 my_uid"
 
+            # 与 HTTP 发送同一道跨账号闸门：不是本账号的会话绝不改写后重发。
+            if not conversation_belongs_to(conversation_id, my_uid):
+                return False, (
+                    f"会话 {conversation_id} 的参与方都不是本账号（uid={my_uid}），"
+                    "拒绝发送：这条会话属于另一个账号"
+                )
+
             conv_id = normalize_conversation_id(conversation_id, my_uid)
             peer_uid = resolve_peer_uid(conv_id, my_uid)
             if not peer_uid:
@@ -1545,6 +1635,7 @@ class DouyinWorker:
                     pw,
                     token_args,
                     headless=browser_headless,
+                    source_ip=await self._resolve_browser_source_ip(),
                 )
                 storage_state = await self._load_storage_state()
                 context = await browser.new_context(
@@ -1780,6 +1871,7 @@ class DouyinWorker:
                 pw,
                 token_args,
                 headless=browser_headless,
+                source_ip=await self._resolve_browser_source_ip(),
             )
             context = await browser.new_context(
                 storage_state=storage_state,
@@ -2382,6 +2474,7 @@ class DouyinWorker:
                 self.playwright,
                 args,
                 headless=browser_headless,
+                source_ip=await self._resolve_browser_source_ip(),
             )
             logger.info(f"Account {self.account_id}: opening browser for IM setup (minimized)")
         except RuntimeError:

backend/rpa_engine/source_bound_proxy.py

@@ -0,0 +1,233 @@
+"""Loopback HTTP proxy whose outbound sockets bind to one local IPv4.
+
+Playwright does not expose a ``local_address`` option.  Accounts that select a
+specific server egress channel therefore use this tiny process-local proxy so
+their browser login/refresh traffic leaves through the same interface as IM
+HTTP and WebSocket traffic.  The listener is loopback-only and does not rotate
+or retry public addresses.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import ipaddress
+import logging
+import socket
+import weakref
+from urllib.parse import urlsplit
+
+logger = logging.getLogger("rpa_engine.source_proxy")
+
+_MAX_HEADER_BYTES = 64 * 1024
+_HEADER_TIMEOUT_SECONDS = 20.0
+
+
+class SourceBoundProxy:
+    """Minimal HTTP/HTTPS CONNECT proxy bound to a fixed source address."""
+
+    def __init__(self, source_ip: str):
+        address = ipaddress.ip_address(str(source_ip or "").strip())
+        if address.version != 4 or address.is_unspecified or address.is_multicast:
+            raise ValueError(f"invalid IPv4 source address: {source_ip!r}")
+        self.source_ip = str(address)
+        self._server: asyncio.AbstractServer | None = None
+
+    @property
+    def server_url(self) -> str:
+        if self._server is None or not self._server.sockets:
+            raise RuntimeError("source-bound proxy has not started")
+        port = int(self._server.sockets[0].getsockname()[1])
+        return f"http://127.0.0.1:{port}"
+
+    async def start(self) -> "SourceBoundProxy":
+        if self._server is None:
+            self._server = await asyncio.start_server(
+                self._handle_client,
+                host="127.0.0.1",
+                port=0,
+                family=socket.AF_INET,
+            )
+            logger.info(
+                "source-bound browser proxy ready: %s -> source %s",
+                self.server_url,
+                self.source_ip,
+            )
+        return self
+
+    async def close(self) -> None:
+        server = self._server
+        self._server = None
+        if server is not None:
+            server.close()
+            await server.wait_closed()
+
+    async def _open_upstream(
+        self,
+        host: str,
+        port: int,
+    ) -> tuple[asyncio.StreamReader, asyncio.StreamWriter]:
+        return await asyncio.open_connection(
+            host=host,
+            port=port,
+            family=socket.AF_INET,
+            local_addr=(self.source_ip, 0),
+        )
+
+    @staticmethod
+    async def _relay(
+        source: asyncio.StreamReader,
+        destination: asyncio.StreamWriter,
+    ) -> None:
+        try:
+            while True:
+                chunk = await source.read(64 * 1024)
+                if not chunk:
+                    break
+                destination.write(chunk)
+                await destination.drain()
+        except (ConnectionError, asyncio.CancelledError):
+            pass
+        finally:
+            try:
+                destination.write_eof()
+            except (AttributeError, OSError, RuntimeError):
+                pass
+
+    @classmethod
+    async def _bridge(
+        cls,
+        client_reader: asyncio.StreamReader,
+        client_writer: asyncio.StreamWriter,
+        upstream_reader: asyncio.StreamReader,
+        upstream_writer: asyncio.StreamWriter,
+    ) -> None:
+        tasks = (
+            asyncio.create_task(cls._relay(client_reader, upstream_writer)),
+            asyncio.create_task(cls._relay(upstream_reader, client_writer)),
+        )
+        try:
+            await asyncio.gather(*tasks)
+        finally:
+            for task in tasks:
+                if not task.done():
+                    task.cancel()
+            await asyncio.gather(*tasks, return_exceptions=True)
+
+    @staticmethod
+    def _parse_authority(authority: str, default_port: int) -> tuple[str, int]:
+        parsed = urlsplit(f"//{authority}")
+        host = str(parsed.hostname or "").strip()
+        if not host:
+            raise ValueError("proxy request is missing a host")
+        return host, int(parsed.port or default_port)
+
+    async def _handle_client(
+        self,
+        client_reader: asyncio.StreamReader,
+        client_writer: asyncio.StreamWriter,
+    ) -> None:
+        upstream_writer: asyncio.StreamWriter | None = None
+        try:
+            header = await asyncio.wait_for(
+                client_reader.readuntil(b"\r\n\r\n"),
+                timeout=_HEADER_TIMEOUT_SECONDS,
+            )
+            if len(header) > _MAX_HEADER_BYTES:
+                raise ValueError("proxy request headers are too large")
+            lines = header.decode("latin-1").split("\r\n")
+            request_line = lines[0].split(" ", 2)
+            if len(request_line) != 3:
+                raise ValueError("malformed proxy request line")
+            method, target, version = request_line
+
+            if method.upper() == "CONNECT":
+                host, port = self._parse_authority(target, 443)
+                upstream_reader, upstream_writer = await self._open_upstream(host, port)
+                client_writer.write(b"HTTP/1.1 200 Connection Established\r\n\r\n")
+                await client_writer.drain()
+            else:
+                parsed = urlsplit(target)
+                host_header = next(
+                    (
+                        line.partition(":")[2].strip()
+                        for line in lines[1:]
+                        if line.lower().startswith("host:")
+                    ),
+                    "",
+                )
+                authority = parsed.netloc or host_header
+                host, port = self._parse_authority(
+                    authority,
+                    443 if parsed.scheme.lower() == "https" else 80,
+                )
+                upstream_reader, upstream_writer = await self._open_upstream(host, port)
+                origin_target = parsed.path or "/"
+                if parsed.query:
+                    origin_target += f"?{parsed.query}"
+                forwarded = [f"{method} {origin_target} {version}"]
+                forwarded.extend(
+                    line for line in lines[1:]
+                    if line and not line.lower().startswith("proxy-connection:")
+                )
+                upstream_writer.write(("\r\n".join(forwarded) + "\r\n\r\n").encode("latin-1"))
+                await upstream_writer.drain()
+
+            await self._bridge(
+                client_reader,
+                client_writer,
+                upstream_reader,
+                upstream_writer,
+            )
+        except asyncio.IncompleteReadError:
+            pass
+        except asyncio.CancelledError:
+            # Event-loop shutdown may cancel an in-flight browser tunnel.
+            # Closing both writers below is sufficient; do not leak a noisy
+            # cancelled handler callback into the server log.
+            pass
+        except Exception as exc:
+            logger.warning("source-bound browser proxy request failed: %s", exc)
+            try:
+                client_writer.write(
+                    b"HTTP/1.1 502 Bad Gateway\r\nConnection: close\r\n\r\n"
+                )
+                await client_writer.drain()
+            except (ConnectionError, RuntimeError):
+                pass
+        finally:
+            for writer in (upstream_writer, client_writer):
+                if writer is None:
+                    continue
+                try:
+                    writer.close()
+                    await writer.wait_closed()
+                except (ConnectionError, RuntimeError):
+                    pass
+
+
+class _LoopProxyState:
+    def __init__(self) -> None:
+        self.lock = asyncio.Lock()
+        self.proxies: dict[str, SourceBoundProxy] = {}
+
+
+_loop_states: weakref.WeakKeyDictionary[
+    asyncio.AbstractEventLoop, _LoopProxyState
+] = weakref.WeakKeyDictionary()
+
+
+async def playwright_proxy_for_source(source_ip: str) -> dict[str, str]:
+    """Return a Playwright proxy config fixed to ``source_ip``."""
+
+    loop = asyncio.get_running_loop()
+    state = _loop_states.get(loop)
+    if state is None:
+        state = _LoopProxyState()
+        _loop_states[loop] = state
+    normalized = str(ipaddress.ip_address(str(source_ip or "").strip()))
+    async with state.lock:
+        proxy = state.proxies.get(normalized)
+        if proxy is None:
+            proxy = await SourceBoundProxy(normalized).start()
+            state.proxies[normalized] = proxy
+    return {"server": proxy.server_url}

backend/tests/test_account_pagination.py

@@ -112,6 +112,40 @@ class AccountPaginationTests(unittest.IsolatedAsyncioTestCase):
         finally:
             main.manager.workers = original_workers
 
+    async def test_account_channel_change_stops_running_worker(self):
+        account = SimpleNamespace(
+            id=2202,
+            egress_public_ip="116.62.23.103",
+            status="online",
+        )
+        db = SimpleNamespace(
+            commit=AsyncMock(),
+            refresh=AsyncMock(),
+            execute=AsyncMock(),
+        )
+
+        with (
+            patch.object(main, "get_owned_account", AsyncMock(return_value=account)),
+            patch.object(main.manager, "is_running", return_value=True),
+            patch.object(main.manager, "stop_worker", AsyncMock(return_value=True)) as stop,
+            patch.object(main, "_build_account_response", return_value={"id": 2202}),
+        ):
+            response = await main.update_account(
+                account_id=2202,
+                body=main.AccountUpdate(egress_public_ip="47.96.154.74"),
+                db=db,
+                user=SimpleNamespace(id=7, role="operator"),
+            )
+
+        self.assertEqual(response, {"id": 2202})
+        self.assertEqual(account.egress_public_ip, "47.96.154.74")
+        stop.assert_awaited_once_with(2202)
+        self.assertEqual(db.commit.await_count, 2)
+        values = db.execute.await_args.args[0].compile().params
+        self.assertIn("已保留登录凭证", values["error_message"])
+        self.assertNotIn("cookie_data", values)
+        self.assertNotIn("im_session_data", values)
+
     async def test_log_stats_uses_one_aggregate_and_respects_ownership(self):
         engine = create_async_engine("sqlite+aiosqlite:///:memory:")
         async with engine.begin() as connection:

backend/tests/test_batch_start_api.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+import json
 import os
 import sys
 import unittest
@@ -262,6 +263,95 @@ class BatchStartApiTests(unittest.IsolatedAsyncioTestCase):
         # return the connection: one before validation, one before the wait.
         self.assertEqual(events, ["release", "assess", "release", "start-worker"])
 
+    async def test_changed_egress_preserves_valid_credentials(self):
+        ready_assessment = {
+            "login_mode": "im_direct",
+            "should_reset": False,
+            "can_skip_browser": True,
+            "message": "ready",
+            "cookie_valid": True,
+            "im_ready": True,
+        }
+        scenarios = (
+            ({"cookies": []}, "47.96.154.74"),
+            ({"cookies": [], "credential_egress_public_ip": "116.62.23.103"}, "47.96.154.74"),
+            ({"cookies": [], "credential_egress_public_ip": "47.96.154.74"}, ""),
+        )
+        modes = (("im_direct", False), (None, False), (None, True))
+        for storage, selected_ip in scenarios:
+            for requested_mode, wait_for_ready in modes:
+                with self.subTest(storage=storage, mode=requested_mode, batch=wait_for_ready):
+                    cookie_data = json.dumps(storage)
+                    account = SimpleNamespace(
+                        id=506,
+                        status="offline",
+                        qr_code_base64=None,
+                        error_message="old channel warning",
+                        cookie_data=cookie_data,
+                        im_session_data="saved-session",
+                        egress_public_ip=selected_ip,
+                    )
+                    db = SimpleNamespace(commit=AsyncMock())
+                    with (
+                        patch.object(main.manager, "is_running", return_value=False),
+                        patch.object(main.manager, "start_worker", AsyncMock(return_value=True)) as start,
+                        patch.object(main, "_get_account_cookie_data", return_value=cookie_data),
+                        patch.object(main, "_reset_account_credentials", AsyncMock()) as reset,
+                        patch.object(main, "assess_account_credential", AsyncMock(return_value=ready_assessment)) as assess,
+                    ):
+                        result = await main._start_account_rpa_impl(
+                            account, db, requested_mode, wait_for_ready=wait_for_ready
+                        )
+
+                    reset.assert_not_awaited()
+                    assess.assert_awaited_once_with(
+                        cookie_data, "saved-session",
+                        startup_priority=True, egress_public_ip=selected_ip,
+                    )
+                    start.assert_awaited_once_with(
+                        506, login_mode="im_direct",
+                        wait_until_ready=wait_for_ready, credential_prevalidated=True,
+                    )
+                    self.assertEqual(account.cookie_data, cookie_data)
+                    self.assertEqual(account.im_session_data, "saved-session")
+                    self.assertIsNone(account.error_message)
+                    self.assertTrue(result["skip_qr"])
+                    self.assertTrue(result["skip_browser"])
+
+    async def test_changed_egress_still_rejects_invalid_im_credentials(self):
+        account = SimpleNamespace(
+            id=506,
+            status="offline",
+            qr_code_base64=None,
+            error_message=None,
+            im_session_data="saved-session",
+            egress_public_ip="47.96.154.74",
+        )
+        db = SimpleNamespace(commit=AsyncMock())
+        invalid_assessment = {
+            "login_mode": "browser",
+            "should_reset": False,
+            "can_skip_browser": False,
+            "message": "缺少 IM 签名密钥（web_protect/keys），请用浏览器登录补全",
+            "cookie_valid": True,
+            "im_ready": False,
+        }
+
+        with (
+            patch.object(main.manager, "is_running", return_value=False),
+            patch.object(main.manager, "start_worker", AsyncMock()) as start,
+            patch.object(main, "_get_account_cookie_data", return_value='{"cookies": []}'),
+            patch.object(main, "_reset_account_credentials", AsyncMock()) as reset,
+            patch.object(main, "assess_account_credential", AsyncMock(return_value=invalid_assessment)),
+        ):
+            with self.assertRaises(main.HTTPException) as error:
+                await main._start_account_rpa_impl(account, db, "im_direct")
+
+        self.assertEqual(error.exception.status_code, 400)
+        self.assertEqual(error.exception.detail, invalid_assessment["message"])
+        reset.assert_not_awaited()
+        start.assert_not_awaited()
+
     async def test_batch_start_does_not_launch_interactive_browser_login(self):
         account = SimpleNamespace(
             id=504,

backend/tests/test_credential_responsiveness.py

@@ -3,10 +3,26 @@ import unittest
 from types import SimpleNamespace
 from unittest.mock import patch
 
-from rpa_engine.credential import validate_im_session
+from rpa_engine.credential import credential_egress_mismatch, validate_im_session
 
 
 class CredentialResponsivenessTests(unittest.IsolatedAsyncioTestCase):
+    def test_legacy_egress_marker_comparison_is_diagnostic(self):
+        legacy = '{"cookies": []}'
+
+        self.assertFalse(credential_egress_mismatch(legacy, ""))
+        self.assertTrue(credential_egress_mismatch(legacy, "47.96.154.74"))
+
+    def test_stamped_egress_marker_comparison(self):
+        stamped = (
+            '{"cookies": [], '
+            '"credential_egress_public_ip": "47.96.154.74"}'
+        )
+
+        self.assertFalse(credential_egress_mismatch(stamped, "47.96.154.74"))
+        self.assertTrue(credential_egress_mismatch(stamped, "116.62.23.103"))
+        self.assertTrue(credential_egress_mismatch(stamped, ""))
+
     async def test_uid_lookup_does_not_block_event_loop(self):
         event_loop_thread_id = threading.get_ident()
         lookup_thread_ids = []

backend/tests/test_cross_account_isolation.py

@@ -0,0 +1,294 @@
+"""托管多个账号时的会话归属隔离回归测试。
+
+复现的缺陷：账号 A 的处理链路收到属于账号 B 的会话（0:1:B:B的好友）后，
+resolve_peer_uid 把末段当成「对方」、normalize_conversation_id 再拼成
+0:1:A:B的好友，于是账号 A 用自己的凭证把自动回复发给了账号 B 的好友。
+"""
+from __future__ import annotations
+
+import asyncio
+import os
+import sys
+import unittest
+from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, Mock, patch
+
+
+BACKEND_DIR = Path(__file__).resolve().parents[1]
+os.environ.setdefault("KEFU_DB_TYPE", "sqlite")
+os.environ.setdefault("KEFU_DATABASE_URL", "")
+os.environ.setdefault("KEFU_DB_PATH", str(BACKEND_DIR / "kefu.db"))
+if str(BACKEND_DIR) not in sys.path:
+    sys.path.insert(0, str(BACKEND_DIR))
+
+from rpa_engine.douyin_im import hosted_registry
+from rpa_engine.douyin_im import ws_client as ws_module
+from rpa_engine.douyin_im.conv_util import conversation_belongs_to
+from rpa_engine.douyin_im.http_client import DouyinImHttpClient
+from rpa_engine.douyin_im.service import DouyinImService
+from rpa_engine.douyin_im.session import DouyinImSession
+from rpa_engine.douyin_im.ws_client import DouyinImWsClient
+
+ACCOUNT_A_UID = 7670159096859706425
+ACCOUNT_B_UID = 7670157997767050299
+PEER_OF_B = 66578464308
+
+
+class ConversationOwnershipTests(unittest.TestCase):
+    def test_foreign_single_chat_is_rejected(self):
+        self.assertFalse(
+            conversation_belongs_to(
+                f"0:1:{ACCOUNT_B_UID}:{PEER_OF_B}", ACCOUNT_A_UID
+            )
+        )
+
+    def test_own_conversation_in_either_position(self):
+        self.assertTrue(
+            conversation_belongs_to(f"0:1:{ACCOUNT_A_UID}:{PEER_OF_B}", ACCOUNT_A_UID)
+        )
+        self.assertTrue(
+            conversation_belongs_to(f"0:1:{PEER_OF_B}:{ACCOUNT_A_UID}", ACCOUNT_A_UID)
+        )
+
+    def test_undecidable_shapes_pass_through(self):
+        # 缺 my_uid / 群聊 / 裸 UID：本来就判不了归属，保守放行
+        self.assertTrue(conversation_belongs_to(f"0:1:{ACCOUNT_B_UID}:{PEER_OF_B}", 0))
+        self.assertTrue(conversation_belongs_to("0:2:123:456", ACCOUNT_A_UID))
+        self.assertTrue(conversation_belongs_to(str(PEER_OF_B), ACCOUNT_A_UID))
+        self.assertTrue(conversation_belongs_to("", ACCOUNT_A_UID))
+
+
+class ForeignMessageDropTests(unittest.IsolatedAsyncioTestCase):
+    def _service(self) -> DouyinImService:
+        service = DouyinImService(
+            session=DouyinImSession(cookies={"sessionid": "a"}, my_uid=ACCOUNT_A_UID),
+            match_reply=AsyncMock(return_value=["自动回复"]),
+            log_fn=AsyncMock(),
+            account_id=1,
+        )
+        service._running = True
+        return service
+
+    async def test_message_from_another_account_never_schedules_a_reply(self):
+        service = self._service()
+        service._resolve_peer_profile = AsyncMock(
+            return_value=("B 的好友", "", str(PEER_OF_B))
+        )
+
+        with patch(
+            "rpa_engine.douyin_im.service.system_logger.record", Mock()
+        ) as record:
+            result = await service._prepare_incoming(
+                {
+                    "conversation_id": f"0:1:{ACCOUNT_B_UID}:{PEER_OF_B}",
+                    "sender_uid": str(PEER_OF_B),
+                    "content": "在吗",
+                    "server_message_id": "7665317099296081465",
+                }
+            )
+
+        self.assertIsNone(result)
+        service.match_reply.assert_not_awaited()
+        service.log_fn.assert_not_awaited()
+        self.assertEqual(service._conv_meta, {})
+        self.assertTrue(record.called)
+
+    async def test_own_message_is_still_processed(self):
+        service = self._service()
+        conv_id = f"0:1:{ACCOUNT_A_UID}:{PEER_OF_B}"
+        service._resolve_peer_profile = AsyncMock(
+            return_value=("我的好友", "", str(PEER_OF_B))
+        )
+        service._resolve_cooldown_seconds = AsyncMock(return_value=0)
+        service._resolve_reply_delay_seconds = AsyncMock(return_value=0)
+        service._send_auto_reply = AsyncMock()
+
+        with patch("rpa_engine.douyin_im.service.system_logger.record", Mock()):
+            send_reply = await service._prepare_incoming(
+                {
+                    "conversation_id": conv_id,
+                    "sender_uid": str(PEER_OF_B),
+                    "content": "在吗",
+                    "server_message_id": "7665317099296081466",
+                }
+            )
+
+        self.assertIsNotNone(send_reply)
+        service.match_reply.assert_awaited()
+        self.assertIn(conv_id, service._conv_meta)
+
+
+class ForeignSendRefusalTests(unittest.IsolatedAsyncioTestCase):
+    async def test_send_refuses_a_conversation_owned_by_another_account(self):
+        client = DouyinImHttpClient(
+            DouyinImSession(cookies={"sessionid": "a"}, my_uid=ACCOUNT_A_UID),
+            account_id=1,
+        )
+        resolve_meta = AsyncMock()
+
+        with (
+            patch.object(
+                DouyinImHttpClient,
+                "_resolve_authoritative_uid",
+                return_value=ACCOUNT_A_UID,
+            ),
+            patch.object(
+                DouyinImHttpClient, "resolve_conversation_meta", resolve_meta
+            ),
+            patch("rpa_engine.douyin_im.http_client.system_logger.record", Mock()),
+        ):
+            sent = await client.send_text_message(
+                f"0:1:{ACCOUNT_B_UID}:{PEER_OF_B}",
+                "你好",
+                _bypass_global_queue=True,
+            )
+
+        self.assertFalse(sent)
+        # 关键断言：拒发必须发生在解析 ticket / 真正写出去之前
+        resolve_meta.assert_not_awaited()
+        self.assertIn("不是本账号", client.last_error)
+        self.assertFalse(client.last_send_channel_retryable)
+
+
+class HostedPeerLoopTests(unittest.IsolatedAsyncioTestCase):
+    """两个本系统托管的账号之间不得互相自动回复（无限回环 → 抖音风控）。"""
+
+    def _service(self) -> DouyinImService:
+        service = DouyinImService(
+            session=DouyinImSession(cookies={"sessionid": "a"}, my_uid=ACCOUNT_A_UID),
+            match_reply=AsyncMock(return_value=["自动回复"]),
+            log_fn=AsyncMock(),
+            account_id=1,
+        )
+        service._running = True
+        service._resolve_cooldown_seconds = AsyncMock(return_value=0)
+        service._resolve_reply_delay_seconds = AsyncMock(return_value=0)
+        return service
+
+    def tearDown(self):
+        hosted_registry.unregister(ACCOUNT_B_UID)
+
+    async def _incoming_from(self, service, peer_uid: int, message_id: str):
+        service._resolve_peer_profile = AsyncMock(
+            return_value=("对方", "", str(peer_uid))
+        )
+        with patch("rpa_engine.douyin_im.service.system_logger.record", Mock()):
+            return await service._prepare_incoming(
+                {
+                    "conversation_id": f"0:1:{ACCOUNT_A_UID}:{peer_uid}",
+                    "sender_uid": str(peer_uid),
+                    "content": "在吗",
+                    "server_message_id": message_id,
+                }
+            )
+
+    async def test_no_auto_reply_to_another_hosted_account(self):
+        hosted_registry.register(ACCOUNT_B_UID)
+        service = self._service()
+
+        result = await self._incoming_from(service, ACCOUNT_B_UID, "1")
+
+        self.assertIsNone(result)
+        service.match_reply.assert_not_awaited()
+        # 消息本身照常入库，只是标记为未回复
+        statuses = [
+            call.kwargs.get("status") for call in service.log_fn.await_args_list
+        ]
+        self.assertIn("received", statuses)
+        self.assertIn("ignored", statuses)
+
+    async def test_ordinary_follower_still_gets_a_reply(self):
+        hosted_registry.register(ACCOUNT_B_UID)
+        service = self._service()
+        service._send_auto_reply = AsyncMock()
+
+        result = await self._incoming_from(service, PEER_OF_B, "2")
+
+        self.assertIsNotNone(result)
+        service.match_reply.assert_awaited()
+
+
+class FrontierDeviceExclusivityTests(unittest.IsolatedAsyncioTestCase):
+    """同一个 frontier 设备号同时只允许一个账号建连。"""
+
+    WS_URL = (
+        "wss://frontier-im.douyin.com/ws/v2?fpid=9&device_id=987654321&"
+        "token=shared-token"
+    )
+
+    def setUp(self):
+        ws_module._FRONTIER_DEVICE_OWNERS.clear()
+
+    def tearDown(self):
+        ws_module._FRONTIER_DEVICE_OWNERS.clear()
+
+    def _client(self, account_id: int) -> DouyinImWsClient:
+        client = DouyinImWsClient(
+            DouyinImSession(cookies={"sessionid": "s"}, ws_urls=[self.WS_URL]),
+            AsyncMock(),
+            account_id=account_id,
+        )
+        client._running = True
+        client._task = SimpleNamespace(done=lambda: False)
+        return client
+
+    def test_second_account_is_denied_while_the_first_holds_the_device(self):
+        first = self._client(11)
+        second = self._client(12)
+
+        self.assertTrue(first._claim_frontier_device(self.WS_URL))
+        self.assertFalse(second._claim_frontier_device(self.WS_URL))
+        self.assertEqual(second._blocked_device_owner_id, 11)
+        # 让出方不会被误标为已占用，重连时仍是 HTTP 轮询兜底
+        self.assertFalse(second.connected)
+
+    def test_device_is_taken_over_after_the_owner_stops(self):
+        first = self._client(11)
+        second = self._client(12)
+        self.assertTrue(first._claim_frontier_device(self.WS_URL))
+
+        first._running = False
+        first._release_frontier_device()
+
+        self.assertTrue(second._claim_frontier_device(self.WS_URL))
+
+    def test_same_account_reconnect_keeps_its_own_device(self):
+        client = self._client(11)
+        self.assertTrue(client._claim_frontier_device(self.WS_URL))
+        self.assertTrue(client._claim_frontier_device(self.WS_URL))
+
+    async def test_run_loop_does_not_open_a_second_connection(self):
+        owner = self._client(11)
+        self.assertTrue(owner._claim_frontier_device(self.WS_URL))
+
+        blocked = self._client(12)
+        blocked._prepare_url = AsyncMock(return_value=self.WS_URL)
+        run_connection = AsyncMock()
+        blocked._run_connection = run_connection
+
+        async def stop_after_first_backoff(_seconds):
+            blocked._running = False
+
+        with (
+            patch.object(ws_module, "_reconnect_delay", return_value=0.0),
+            patch.object(ws_module.system_logger, "record") as record,
+            patch.object(ws_module.asyncio, "sleep", stop_after_first_backoff),
+        ):
+            await asyncio.wait_for(blocked._run_loop(self.WS_URL), timeout=1.0)
+
+        run_connection.assert_not_awaited()
+        self.assertFalse(blocked.connected)
+        self.assertTrue(record.called)
+
+    def test_url_without_device_id_is_not_blocked(self):
+        first = self._client(11)
+        second = self._client(12)
+        url = "wss://frontier-im.douyin.com/ws/v2?fpid=9&token=t"
+
+        self.assertTrue(first._claim_frontier_device(url))
+        self.assertTrue(second._claim_frontier_device(url))
+
+
+if __name__ == "__main__":
+    unittest.main()

backend/tests/test_egress_channels.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 import os
 import sys
 import time
@@ -25,6 +26,7 @@ from rpa_engine.egress_channels import (
     reset_egress_cache_for_tests,
     resolve_send_channels,
 )
+from rpa_engine.source_bound_proxy import SourceBoundProxy
 from models.db_migrate import migrate_accounts_table
 from models.models import Account
 
@@ -99,6 +101,49 @@ class EgressChannelTests(unittest.IsolatedAsyncioTestCase):
             with self.assertRaises(EgressChannelUnavailable):
                 await resolve_send_channels("198.51.100.99", 2)
 
+    async def test_browser_proxy_binds_selected_source_address(self):
+        observed_peer = asyncio.get_running_loop().create_future()
+
+        async def target_handler(reader, writer):
+            if not observed_peer.done():
+                observed_peer.set_result(writer.get_extra_info("peername")[0])
+            payload = await reader.readexactly(4)
+            writer.write(payload)
+            await writer.drain()
+            writer.close()
+            await writer.wait_closed()
+
+        target = await asyncio.start_server(target_handler, "127.0.0.1", 0)
+        target_port = target.sockets[0].getsockname()[1]
+        proxy = await SourceBoundProxy("127.0.0.2").start()
+        writer = None
+        try:
+            reader, writer = await asyncio.open_connection(
+                "127.0.0.1",
+                int(proxy.server_url.rpartition(":")[2]),
+            )
+            writer.write(
+                (
+                    f"CONNECT 127.0.0.1:{target_port} HTTP/1.1\r\n"
+                    f"Host: 127.0.0.1:{target_port}\r\n\r\n"
+                ).encode("ascii")
+            )
+            await writer.drain()
+            response = await reader.readuntil(b"\r\n\r\n")
+            self.assertIn(b"200 Connection Established", response)
+
+            writer.write(b"ping")
+            await writer.drain()
+            self.assertEqual(await reader.readexactly(4), b"ping")
+            self.assertEqual(await asyncio.wait_for(observed_peer, 1), "127.0.0.2")
+        finally:
+            if writer is not None:
+                writer.close()
+                await writer.wait_closed()
+            await proxy.close()
+            target.close()
+            await target.wait_closed()
+
 
 class EgressMigrationTests(unittest.TestCase):
     def test_mysql_accounts_uses_longtext_for_browser_payloads(self):

backend/tests/test_reply_queue_integration.py

@@ -18,6 +18,8 @@ if str(BACKEND_DIR) not in sys.path:
 
 from auth.system_settings import SystemSettingsData, set_cached_settings
 from rpa_engine.douyin_im.service import DouyinImService
+from rpa_engine.douyin_im.session import DouyinImSession
+from rpa_engine.douyin_im import service as service_module
 from rpa_engine.playwright_worker import DouyinWorker
 
 
@@ -114,6 +116,74 @@ def _build_service(delay_seconds: int = 60):
 
 
 class ReplyQueueIntegrationTests(unittest.IsolatedAsyncioTestCase):
+    async def test_kick_does_not_replay_through_browser_fallback(self):
+        callback = AsyncMock()
+        fallback = AsyncMock(return_value=(True, "must not run"))
+        session = DouyinImSession(cookies={"sessionid": "test"}, my_uid=999)
+        service = DouyinImService(
+            session=session,
+            match_reply=AsyncMock(),
+            log_fn=AsyncMock(),
+            account_id=1,
+            send_fallback=fallback,
+            on_session_invalid=callback,
+        )
+        service._running = True
+        kicked_http = SimpleNamespace(
+            send_text_message=AsyncMock(return_value=False),
+            last_error="decision=KICK",
+            last_send_needs_refresh=False,
+        )
+        context = AsyncMock()
+        context.__aenter__.return_value = kicked_http
+        context.__aexit__.return_value = None
+
+        with (
+            unittest.mock.patch.object(
+                service_module, "DouyinImHttpClient", return_value=context
+            ),
+            unittest.mock.patch(
+                "rpa_engine.douyin_im.service.system_logger.record", Mock()
+            ),
+        ):
+            sent, _ = await service._send_text("0:1:999:123", "hello")
+
+        self.assertFalse(sent)
+        fallback.assert_not_awaited()
+        callback.assert_awaited_once()
+
+    async def test_fresh_session_replaces_send_and_ws_state_atomically(self):
+        current = DouyinImSession(
+            cookies={"sessionid": "old"},
+            my_uid=999,
+            conv_meta={"old": {"ticket": "one"}},
+        )
+        current.egress_public_ip = "203.0.113.10"
+        current.egress_source_ip = "10.0.0.10"
+        current.egress_auto_attempts = 2
+        service = DouyinImService(
+            session=current,
+            match_reply=AsyncMock(),
+            log_fn=AsyncMock(),
+            account_id=1,
+        )
+        service._ws_client = SimpleNamespace(session=current)
+        fresh = DouyinImSession(
+            cookies={"sessionid": "fresh"},
+            my_uid=999,
+            conv_meta={"new": {"ticket": "two"}},
+        )
+
+        await service.replace_session(fresh)
+
+        self.assertIs(service.session, fresh)
+        self.assertIs(service._ws_client.session, fresh)
+        self.assertEqual(service.session.cookies["sessionid"], "fresh")
+        self.assertEqual(set(service.session.conv_meta), {"old", "new"})
+        self.assertEqual(service.session.egress_public_ip, "203.0.113.10")
+        self.assertEqual(service.session.egress_source_ip, "10.0.0.10")
+        self.assertEqual(service.session.egress_auto_attempts, 2)
+
     async def test_kick_response_takes_account_offline_immediately(self):
         callback = AsyncMock()
         service, _, _ = _build_service()

backend/tests/test_send_entry_and_worker_lifecycle.py

@@ -205,7 +205,7 @@ class SendTextMessageEntryTests(unittest.IsolatedAsyncioTestCase):
         self.assertTrue(client.last_send_needs_refresh)
         self.assertEqual(client.last_request_debug, "response status=401")
 
-    async def test_retryable_rejection_switches_channels_serially(self):
+    async def test_retryable_network_failure_switches_channels_serially(self):
         client = self._make_client(account_id=89)
         client.session.egress_auto_attempts = 2
         routes = [
@@ -216,7 +216,7 @@ class SendTextMessageEntryTests(unittest.IsolatedAsyncioTestCase):
         first = SimpleNamespace(
             send_text_message=AsyncMock(return_value=False),
             last_send_meta={},
-            last_error="decision=KICK",
+            last_error="connect timeout",
             last_send_needs_refresh=False,
             last_send_channel_retryable=True,
             last_request_debug="first route",
@@ -264,8 +264,82 @@ class SendTextMessageEntryTests(unittest.IsolatedAsyncioTestCase):
         second.send_text_message.assert_awaited_once()
         self.assertEqual(client.last_request_debug, "second route")
 
+    async def test_kick_never_switches_public_channels(self):
+        client = self._make_client(account_id=90)
+        client.session.egress_auto_attempts = 2
+        routes = [
+            EgressChannel("198.51.100.10", "10.0.0.10", "eth0", True),
+            EgressChannel("198.51.100.11", "10.0.0.11", "eth1", False),
+        ]
+        kicked = SimpleNamespace(
+            send_text_message=AsyncMock(return_value=False),
+            last_send_meta={},
+            last_error="decision=KICK",
+            last_send_needs_refresh=False,
+            last_send_channel_retryable=False,
+            last_request_debug="terminal kick",
+        )
+        context = MagicMock()
+        context.__aenter__ = AsyncMock(return_value=kicked)
+        context.__aexit__ = AsyncMock(return_value=None)
+        queued_factory = MagicMock(return_value=context)
+
+        async def execute_submission(account_id, operation, description=""):
+            return await operation()
+
+        with (
+            patch(
+                "rpa_engine.douyin_im.traffic_control.submit_outbound",
+                AsyncMock(side_effect=execute_submission),
+            ),
+            patch(
+                "rpa_engine.douyin_im.http_client.resolve_send_channels",
+                AsyncMock(return_value=routes),
+            ),
+            patch.object(http_client_module, "DouyinImHttpClient", queued_factory),
+        ):
+            sent = await client.send_text_message("0:1:10001:20002", "hello")
+
+        self.assertFalse(sent)
+        queued_factory.assert_called_once()
+        kicked.send_text_message.assert_awaited_once()
+
 
 class WorkerLifecycleTests(unittest.IsolatedAsyncioTestCase):
+    async def test_browser_launch_uses_selected_source_proxy(self):
+        launch = AsyncMock(return_value="browser")
+        pw = SimpleNamespace(chromium=SimpleNamespace(launch=launch))
+        source_proxy = AsyncMock(return_value={"server": "http://127.0.0.1:43210"})
+
+        with (
+            patch.object(
+                playwright_worker_module,
+                "ensure_browser_display",
+                AsyncMock(),
+            ),
+            patch.object(
+                playwright_worker_module,
+                "playwright_proxy_for_source",
+                source_proxy,
+            ),
+            patch.object(playwright_worker_module, "playwright_proxy") as global_proxy,
+        ):
+            browser = await playwright_worker_module._launch_chromium(
+                pw,
+                ["--no-sandbox"],
+                headless=True,
+                source_ip="10.0.0.6",
+            )
+
+        self.assertEqual(browser, "browser")
+        source_proxy.assert_awaited_once_with("10.0.0.6")
+        global_proxy.assert_not_called()
+        launch.assert_awaited_once_with(
+            headless=True,
+            args=["--no-sandbox"],
+            proxy={"server": "http://127.0.0.1:43210"},
+        )
+
     async def test_virtual_display_starts_before_playwright_driver(self):
         ensure_display = AsyncMock()