refactor(task): 拆分 TaskService 并重构任务生命周期

- 将 task 公共协议/上下文/异常/schema 下沉到 core，并迁移 polling 目录
- 新增 execute/submit/video 子模块，拆分同步执行、异步提交流程、错误处理与视频任务操作
- 收敛 TaskService 为门面编排，内部委派到 SyncTaskExecutionService、AsyncTaskSubmitService、VideoTaskOperationsService
- 重构 main 生命周期管理：引入 LifecycleState，拆分启动与关闭流程
- 删除未使用的 TaskExecuteFacadeService 与 TaskSubmitFacadeService

Closes #201

Co-authored-by: AAEE86 <ppk0227@hotmail.com>

src/api/admin/provider_query.py

@@ -1956,11 +1956,14 @@ async def test_model_failover(
     - direct: 直接测试 provider_model_name，在当前 Provider 内多 Key 故障转移
     """
     from src.core.exceptions import ProviderNotAvailableException
+    from src.services.candidate.failover import FailoverEngine
+    from src.services.candidate.policy import RetryMode, RetryPolicy, SkipPolicy
     from src.services.candidate.recorder import CandidateRecorder
     from src.services.scheduling.candidate_builder import CandidateBuilder
     from src.services.scheduling.candidate_sorter import CandidateSorter
     from src.services.scheduling.scheduling_config import SchedulingConfig
     from src.services.task import TaskService
+    from src.services.task.core.protocol import AttemptKind, AttemptResult
 
     provider = (
         db.query(Provider)

src/api/handlers/base/chat_handler_base.py

@@ -557,7 +557,7 @@ class ChatHandlerBase(BaseMessageHandler, ABC):
 
             # 统一入口：总是通过 TaskService
             from src.services.task import TaskService
-            from src.services.task.context import TaskMode
+            from src.services.task.core.context import TaskMode
 
             exec_result = await TaskService(self.db, self.redis).execute(
                 task_type="chat",

src/api/handlers/base/chat_sync_executor.py

@@ -161,7 +161,7 @@ class ChatSyncExecutor:
 
             # 统一入口：总是通过 TaskService
             from src.services.task import TaskService
-            from src.services.task.context import TaskMode
+            from src.services.task.core.context import TaskMode
 
             exec_result = await TaskService(handler.db, handler.redis).execute(
                 task_type="chat",

src/api/handlers/base/cli_stream_mixin.py

@@ -162,7 +162,7 @@ class CliStreamMixin:
 
             # 统一入口：总是通过 TaskService
             from src.services.task import TaskService
-            from src.services.task.context import TaskMode
+            from src.services.task.core.context import TaskMode
 
             exec_result = await TaskService(self.db, self.redis).execute(
                 task_type="cli",

src/api/handlers/base/cli_sync_mixin.py

@@ -482,7 +482,7 @@ class CliSyncMixin:
 
             # 统一入口：总是通过 TaskService
             from src.services.task import TaskService
-            from src.services.task.context import TaskMode
+            from src.services.task.core.context import TaskMode
 
             exec_result = await TaskService(self.db, self.redis).execute(
                 task_type="cli",

src/main.py

@@ -6,7 +6,8 @@
 from __future__ import annotations
 
 from contextlib import asynccontextmanager
-from typing import Any
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING, Any
 
 import uvicorn
 from fastapi import FastAPI, HTTPException
@@ -32,6 +33,20 @@ from src.database import init_db
 from src.middleware.plugin_middleware import PluginMiddleware
 from src.plugins.manager import get_plugin_manager
 
+if TYPE_CHECKING:
+    from redis.asyncio.client import Redis
+
+    from src.core.modules.base import ModuleDefinition
+    from src.plugins.manager import PluginManager
+    from src.services.model.fetch_scheduler import ModelFetchScheduler
+    from src.services.provider_keys.pool_quota_probe_scheduler import PoolQuotaProbeScheduler
+    from src.services.rate_limit.concurrency_manager import ConcurrencyManager
+    from src.services.system.maintenance_scheduler import MaintenanceScheduler
+    from src.services.system.scheduler import TaskScheduler
+    from src.services.task.polling.task_poller import TaskPollerService
+    from src.services.usage.quota_scheduler import QuotaScheduler
+    from src.utils.task_coordinator import StartupTaskCoordinator
+
 
 async def initialize_providers() -> None:
     """从数据库初始化提供商（仅用于日志记录）"""
@@ -76,23 +91,41 @@ async def initialize_providers() -> None:
         logger.exception("从数据库初始化提供商失败")
 
 
-@asynccontextmanager
+@dataclass
-async def lifespan(app: FastAPI) -> Any:
+class LifecycleState:
-    """应用生命周期管理"""
+    """应用生命周期阶段共享的运行时状态。"""
-    # 禁用uvicorn的access日志(在子进程中执行)
+
+    redis_client: Redis | None = None
+    concurrency_manager: ConcurrencyManager | None = None
+    plugin_manager: PluginManager | None = None
+    available_modules: list[ModuleDefinition] = field(default_factory=list)
+    task_coordinator: StartupTaskCoordinator | None = None
+    quota_scheduler: QuotaScheduler | None = None
+    maintenance_scheduler: MaintenanceScheduler | None = None
+    model_fetch_scheduler: ModelFetchScheduler | None = None
+    pool_quota_probe_scheduler: PoolQuotaProbeScheduler | None = None
+    task_poller: TaskPollerService | None = None
+    task_scheduler: TaskScheduler | None = None
+
+
+def _configure_uvicorn_access_log() -> None:
+    """禁用 uvicorn access 日志（在子进程中执行）。"""
     import logging
 
     logging.getLogger("uvicorn.access").setLevel(logging.CRITICAL)
     logging.getLogger("uvicorn.access").disabled = True
 
-    # 启动时执行
+
+def _log_startup_banner() -> None:
     logger.info("=" * 60)
     from src import __version__
 
     logger.info(f"AI Proxy v{__version__} - GlobalModel Architecture")
     logger.info("=" * 60)
 
-    # 安全配置验证（生产环境会阻止启动）
+
+def _validate_security_or_raise() -> None:
+    """启动前安全配置校验。"""
     security_errors = config.validate_security_config()
     if security_errors:
         for error in security_errors:
@@ -104,6 +137,9 @@ async def lifespan(app: FastAPI) -> Any:
                 + "\n".join(f"  - {e}" for e in security_errors)
             )
 
+
+async def _initialize_core_infrastructure(state: LifecycleState) -> None:
+    """初始化数据库、缓存、并发与基础后台组件。"""
     # 记录启动警告（密码、连接池、JWT 等）
     config.log_startup_warnings()
 
@@ -122,10 +158,9 @@ async def lifespan(app: FastAPI) -> Any:
     logger.info("初始化全局Redis客户端...")
     from src.clients.redis_client import get_redis_client
 
-    redis_client = None
     try:
-        redis_client = await get_redis_client(require_redis=config.require_redis)
+        state.redis_client = await get_redis_client(require_redis=config.require_redis)
-        if redis_client:
+        if state.redis_client:
             logger.info("[OK] Redis客户端初始化成功，缓存亲和性功能已启用")
         else:
             logger.warning(
@@ -136,13 +171,13 @@ async def lifespan(app: FastAPI) -> Any:
             logger.exception("[ERROR] Redis连接失败，应用启动中止")
             raise
         logger.warning(f"Redis连接失败，但配置允许降级，将继续使用内存模式: {e}")
-        redis_client = None
+        state.redis_client = None
 
     # 初始化并发管理器（内部会使用Redis）
     logger.info("初始化并发管理器...")
     from src.services.rate_limit.concurrency_manager import get_concurrency_manager
 
-    concurrency_manager = await get_concurrency_manager()
+    state.concurrency_manager = await get_concurrency_manager()
 
     # 初始化批量提交器（提升数据库并发能力）
     logger.info("初始化批量提交器...")
@@ -167,10 +202,13 @@ async def lifespan(app: FastAPI) -> Any:
 
         await start_usage_queue_consumer()
 
+
+async def _initialize_plugins_and_modules(app: FastAPI, state: LifecycleState) -> None:
+    """初始化插件系统、模块系统，并注册路由与钩子。"""
     # 初始化插件系统
     logger.info("初始化插件系统...")
-    plugin_manager = get_plugin_manager()
+    state.plugin_manager = get_plugin_manager()
-    init_results = await plugin_manager.initialize_all()
+    init_results = await state.plugin_manager.initialize_all()
     successful = sum(1 for success in init_results.values() if success)
     logger.info(f"插件初始化完成: {successful}/{len(init_results)} 个插件成功启动")
 
@@ -204,8 +242,8 @@ async def lifespan(app: FastAPI) -> Any:
 
     # 注册可用模块的路由
     # 注意：模块的 router 自带 prefix，api_prefix 字段仅用于日志和文档
-    available_modules = module_registry.get_available_modules()
+    state.available_modules = module_registry.get_available_modules()
-    for module in available_modules:
+    for module in state.available_modules:
         if module.router_factory:
             router = module.router_factory()
             app.include_router(router)
@@ -216,7 +254,7 @@ async def lifespan(app: FastAPI) -> Any:
         if module.on_startup:
             await module.on_startup()
 
-    logger.info(f"功能模块初始化完成: {len(available_modules)}/{len(ALL_MODULES)} 个模块可用")
+    logger.info(f"功能模块初始化完成: {len(state.available_modules)}/{len(ALL_MODULES)} 个模块可用")
 
     # 显式 bootstrap provider plugins（注册 envelope/enricher 等）
     # 使 core/provider_oauth_utils 不需要在运行时 lazy import services 层
@@ -229,9 +267,9 @@ async def lifespan(app: FastAPI) -> Any:
 
     register_default_parsers()
 
-    logger.info(f"服务启动成功: http://{config.host}:{config.port}")
-    logger.info("=" * 60)
 
+async def _start_background_services(state: LifecycleState) -> None:
+    """启动调度器与后台轮询服务。"""
     # 启动月卡额度重置调度器（仅一个 worker 执行）
     logger.info("启动月卡额度重置调度器...")
     from src.services.model.fetch_scheduler import get_model_fetch_scheduler
@@ -239,75 +277,92 @@ async def lifespan(app: FastAPI) -> Any:
         get_pool_quota_probe_scheduler,
     )
     from src.services.system.maintenance_scheduler import get_maintenance_scheduler
-    from src.services.task.task_poller import get_task_poller
+    from src.services.task.polling.task_poller import get_task_poller
     from src.services.usage.quota_scheduler import get_quota_scheduler
     from src.utils.task_coordinator import StartupTaskCoordinator
 
-    quota_scheduler = get_quota_scheduler()
+    state.quota_scheduler = get_quota_scheduler()
-    maintenance_scheduler = get_maintenance_scheduler()
+    state.maintenance_scheduler = get_maintenance_scheduler()
-    model_fetch_scheduler = get_model_fetch_scheduler()
+    state.model_fetch_scheduler = get_model_fetch_scheduler()
-    pool_quota_probe_scheduler = get_pool_quota_probe_scheduler()
+    state.pool_quota_probe_scheduler = get_pool_quota_probe_scheduler()
-    task_poller = get_task_poller()
+    state.task_poller = get_task_poller()
-    task_coordinator = StartupTaskCoordinator(redis_client)
+    state.task_coordinator = StartupTaskCoordinator(state.redis_client)
 
     # 启动额度调度器
-    quota_scheduler_active = await task_coordinator.acquire("quota_scheduler")
+    quota_scheduler_active = await state.task_coordinator.acquire("quota_scheduler")
     if quota_scheduler_active:
-        await quota_scheduler.start()
+        await state.quota_scheduler.start()
     else:
         logger.info("检测到其他 worker 已运行额度调度器，本实例跳过")
-        quota_scheduler = None  # type: ignore[assignment]
+        state.quota_scheduler = None
 
     # 启动维护调度器
-    maintenance_scheduler_active = await task_coordinator.acquire("maintenance_scheduler")
+    maintenance_scheduler_active = await state.task_coordinator.acquire("maintenance_scheduler")
     if maintenance_scheduler_active:
         logger.info("启动系统维护调度器...")
-        await maintenance_scheduler.start()
+        await state.maintenance_scheduler.start()
     else:
         logger.info("检测到其他 worker 已运行维护调度器，本实例跳过")
-        maintenance_scheduler = None  # type: ignore[assignment]
+        state.maintenance_scheduler = None
 
     # 启动模型自动获取调度器
-    model_fetch_scheduler_active = await task_coordinator.acquire("model_fetch_scheduler")
+    model_fetch_scheduler_active = await state.task_coordinator.acquire("model_fetch_scheduler")
     if model_fetch_scheduler_active:
         logger.info("启动模型自动获取调度器...")
-        await model_fetch_scheduler.start()
+        await state.model_fetch_scheduler.start()
     else:
         logger.info("检测到其他 worker 已运行模型获取调度器，本实例跳过")
-        model_fetch_scheduler = None  # type: ignore[assignment]
+        state.model_fetch_scheduler = None
 
     # 启动号池额度主动探测调度器
-    pool_quota_probe_scheduler_active = await task_coordinator.acquire("pool_quota_probe_scheduler")
+    pool_quota_probe_scheduler_active = await state.task_coordinator.acquire("pool_quota_probe_scheduler")
     if pool_quota_probe_scheduler_active:
         logger.info("启动号池额度主动探测调度器...")
-        await pool_quota_probe_scheduler.start()
+        await state.pool_quota_probe_scheduler.start()
     else:
         logger.info("检测到其他 worker 已运行号池额度主动探测调度器，本实例跳过")
-        pool_quota_probe_scheduler = None  # type: ignore[assignment]
+        state.pool_quota_probe_scheduler = None
 
     # 启动异步任务轮询服务（当前仅视频）
-    task_poller_active = await task_coordinator.acquire("task_poller:video")
+    task_poller_active = await state.task_coordinator.acquire("task_poller:video")
     if task_poller_active:
         logger.info("启动 TaskPoller（video）...")
-        await task_poller.start()
+        await state.task_poller.start()
     else:
         logger.info("检测到其他 worker 已运行 TaskPoller（video），本实例跳过")
-        task_poller = None  # type: ignore[assignment]
+        state.task_poller = None
 
     # 启动统一的定时任务调度器
     from src.services.system.scheduler import get_scheduler
 
-    task_scheduler = get_scheduler()
+    state.task_scheduler = get_scheduler()
-    task_scheduler.start()
+    state.task_scheduler.start()
 
     # 启动缓存预热（后台任务，不阻塞启动）
     from src.services.system.cache_warmup import start_cache_warmup
 
     await start_cache_warmup()
 
-    yield  # 应用运行期间
 
-    # 关闭时执行
+async def _run_startup(app: FastAPI) -> LifecycleState:
+    """执行完整启动流程并返回生命周期状态。"""
+    _configure_uvicorn_access_log()
+    _log_startup_banner()
+    _validate_security_or_raise()
+
+    state = LifecycleState()
+    await _initialize_core_infrastructure(state)
+    await _initialize_plugins_and_modules(app, state)
+
+    logger.info(f"服务启动成功: http://{config.host}:{config.port}")
+    logger.info("=" * 60)
+
+    await _start_background_services(state)
+    return state
+
+
+async def _run_shutdown(state: LifecycleState) -> None:
+    """执行完整关闭流程。"""
     logger.info("正在关闭服务...")
 
     # 停止 Codex 配额异步同步器（停止前会 flush 待同步事件）
@@ -334,52 +389,58 @@ async def lifespan(app: FastAPI) -> Any:
         await stop_usage_queue_consumer()
 
     # 停止维护调度器
-    if maintenance_scheduler:
+    if state.maintenance_scheduler:
         logger.info("停止系统维护调度器...")
-        await maintenance_scheduler.stop()
+        await state.maintenance_scheduler.stop()
-        await task_coordinator.release("maintenance_scheduler")
+        if state.task_coordinator:
+            await state.task_coordinator.release("maintenance_scheduler")
 
     # 停止月卡额度重置调度器，并释放分布式锁
+    if state.quota_scheduler:
         logger.info("停止月卡额度重置调度器...")
-    if quota_scheduler:
+        await state.quota_scheduler.stop()
-        await quota_scheduler.stop()
+        if state.task_coordinator:
-    if task_coordinator:
+            await state.task_coordinator.release("quota_scheduler")
-        await task_coordinator.release("quota_scheduler")
 
     # 停止模型自动获取调度器
-    if model_fetch_scheduler:
+    if state.model_fetch_scheduler:
         logger.info("停止模型自动获取调度器...")
-        await model_fetch_scheduler.stop()
+        await state.model_fetch_scheduler.stop()
-        await task_coordinator.release("model_fetch_scheduler")
+        if state.task_coordinator:
+            await state.task_coordinator.release("model_fetch_scheduler")
 
-    if pool_quota_probe_scheduler:
+    if state.pool_quota_probe_scheduler:
         logger.info("停止号池额度主动探测调度器...")
-        await pool_quota_probe_scheduler.stop()
+        await state.pool_quota_probe_scheduler.stop()
-        await task_coordinator.release("pool_quota_probe_scheduler")
+        if state.task_coordinator:
+            await state.task_coordinator.release("pool_quota_probe_scheduler")
 
-    if task_poller:
+    if state.task_poller:
         logger.info("停止 TaskPoller（video）...")
-        await task_poller.stop()
+        await state.task_poller.stop()
-        await task_coordinator.release("task_poller:video")
+        if state.task_coordinator:
+            await state.task_coordinator.release("task_poller:video")
 
     # 停止统一的定时任务调度器
     logger.info("停止定时任务调度器...")
-    task_scheduler.stop()
+    if state.task_scheduler:
+        state.task_scheduler.stop()
 
     # 关闭插件系统
     logger.info("关闭插件系统...")
-    await plugin_manager.shutdown_all()
+    if state.plugin_manager:
+        await state.plugin_manager.shutdown_all()
 
     # 关闭功能模块
     logger.info("关闭功能模块...")
-    for module in available_modules:
+    for module in state.available_modules:
         if module.on_shutdown:
             await module.on_shutdown()
 
     # 关闭并发管理器
     logger.info("关闭并发管理器...")
-    if concurrency_manager:
+    if state.concurrency_manager:
-        await concurrency_manager.close()
+        await state.concurrency_manager.close()
 
     # 关闭全局Redis客户端
     logger.info("关闭全局Redis客户端...")
@@ -394,6 +455,16 @@ async def lifespan(app: FastAPI) -> Any:
     logger.info("服务已关闭")
 
 
+@asynccontextmanager
+async def lifespan(app: FastAPI) -> Any:
+    """应用生命周期管理"""
+    state = await _run_startup(app)
+    try:
+        yield  # 应用运行期间
+    finally:
+        await _run_shutdown(state)
+
+
 from src import __version__ as app_version
 
 # OpenAPI Tags 元数据定义

src/services/candidate/failover.py

@@ -16,9 +16,9 @@ from src.models.database import RequestCandidate
 from src.services.orchestration.error_classifier import ErrorAction, ErrorClassifier
 from src.services.request.candidate import RequestCandidateService
 from src.services.scheduling.schemas import PoolCandidate, ProviderCandidate
-from src.services.task.exceptions import StreamProbeError
+from src.services.task.core.exceptions import StreamProbeError
-from src.services.task.protocol import AttemptFunc, AttemptKind, AttemptResult
+from src.services.task.core.protocol import AttemptFunc, AttemptKind, AttemptResult
-from src.services.task.schema import ExecutionResult
+from src.services.task.core.schema import ExecutionResult
 
 from .policy import FailoverAction, RetryMode, RetryPolicy, SkipPolicy
 from .recorder import CandidateRecorder

src/services/task/execute/error_handler.py

@@ -0,0 +1,512 @@
+from __future__ import annotations
+
+from typing import Any
+
+import httpx
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.core.error_utils import extract_error_message
+from src.core.exceptions import (
+    ConcurrencyLimitError,
+    EmbeddedErrorException,
+    ProxyNodeUnavailableError,
+    ThinkingSignatureException,
+    UpstreamClientException,
+)
+from src.core.logger import logger
+from src.core.provider_types import ProviderType
+from src.services.request.candidate import RequestCandidateService
+from src.services.task.execute.pool import TaskPoolOperationsService
+
+
+class TaskErrorOperationsService:
+    """任务执行错误处理服务（候选失败分类、整流与状态回写）。"""
+
+    def __init__(self, db: Session, *, pool_ops: TaskPoolOperationsService) -> None:
+        self.db = db
+        self._pool_ops = pool_ops
+
+    def mark_thinking_error_failed(
+        self,
+        candidate_record_id: str,
+        error: Any,
+        elapsed_ms: int,
+        captured_key_concurrent: int | None,
+        extra_data: dict[str, Any],
+    ) -> None:
+        """Mark ThinkingSignatureException as failed for the candidate."""
+        if not isinstance(error, ThinkingSignatureException):
+            return
+
+        RequestCandidateService.mark_candidate_failed(
+            db=self.db,
+            candidate_id=candidate_record_id,
+            error_type="ThinkingSignatureException",
+            error_message=str(error),
+            status_code=400,
+            latency_ms=elapsed_ms,
+            concurrent_requests=captured_key_concurrent,
+            extra_data=extra_data,
+        )
+
+    def handle_thinking_signature_error(
+        self,
+        *,
+        converted_error: Any,
+        provider_type: str | None,
+        model_name: str | None,
+        request_id: str | None,
+        candidate_record_id: str,
+        elapsed_ms: int,
+        captured_key_concurrent: int | None,
+        serializable_extra_data: dict[str, Any],
+        request_body_ref: dict[str, Any] | None,
+    ) -> str:
+        """Try to rectify thinking signature errors and request a retry."""
+        from src.services.message.thinking_rectifier import ThinkingRectifier
+
+        if not isinstance(converted_error, ThinkingSignatureException):
+            raise converted_error
+
+        if not config.thinking_rectifier_enabled:
+            logger.info("  [{}] Thinking 错误：整流器已禁用，终止重试", request_id)
+            self.mark_thinking_error_failed(
+                candidate_record_id,
+                converted_error,
+                elapsed_ms,
+                captured_key_concurrent,
+                serializable_extra_data,
+            )
+            raise converted_error
+
+        if request_body_ref is None:
+            logger.warning("  [{}] Thinking 错误：无法获取请求体引用，终止重试", request_id)
+            self.mark_thinking_error_failed(
+                candidate_record_id,
+                converted_error,
+                elapsed_ms,
+                captured_key_concurrent,
+                serializable_extra_data,
+            )
+            raise converted_error
+
+        provider_type_norm = str(provider_type or "").lower()
+
+        # Rectification may have multiple stages (Antigravity only).
+        stage_raw = request_body_ref.get("_rectify_stage", 0)
+        try:
+            stage = int(stage_raw or 0)
+        except Exception:
+            stage = 0
+        if stage <= 0 and request_body_ref.get("_rectified", False):
+            stage = 1
+
+        if stage >= 2 or (stage >= 1 and provider_type_norm != ProviderType.ANTIGRAVITY):
+            logger.warning("  [{}] Thinking 错误：已整流仍失败，终止重试", request_id)
+            self.mark_thinking_error_failed(
+                candidate_record_id,
+                converted_error,
+                elapsed_ms,
+                captured_key_concurrent,
+                {**serializable_extra_data, "rectified": True, "rectify_stage": stage},
+            )
+            raise converted_error
+
+        request_body = request_body_ref.get("body", {})
+
+        stage_label = "thinking_only"
+        next_stage = 1
+        if stage == 0:
+            rectified_body, modified = ThinkingRectifier.rectify(request_body)
+            stage_label = "thinking_only"
+            next_stage = 1
+        else:
+            # Stage 2 only applies to Antigravity.
+            rectified_body, modified = ThinkingRectifier.rectify_signature_sensitive_blocks(
+                request_body
+            )
+            stage_label = "thinking_and_tools"
+            next_stage = 2
+
+        if modified:
+            request_body_ref["body"] = rectified_body
+            request_body_ref["_rectified"] = True
+            request_body_ref["_rectified_this_turn"] = True
+            request_body_ref["_rectify_stage"] = next_stage
+
+            if provider_type_norm == ProviderType.ANTIGRAVITY:
+                try:
+                    from src.core.metrics import antigravity_degradation_total
+
+                    antigravity_degradation_total.labels(
+                        stage=stage_label,
+                        model=str(model_name or "unknown"),
+                    ).inc()
+                except Exception:
+                    pass
+
+            logger.info(
+                "  [{}] 请求已整流(stage={})，在当前候选上重试",
+                request_id,
+                next_stage,
+            )
+            self.mark_thinking_error_failed(
+                candidate_record_id,
+                converted_error,
+                elapsed_ms,
+                captured_key_concurrent,
+                {
+                    **serializable_extra_data,
+                    "rectified": True,
+                    "rectify_stage": next_stage,
+                    "rectify_stage_label": stage_label,
+                },
+            )
+            return "continue"
+
+        logger.warning("  [{}] Thinking 错误：无可整流内容", request_id)
+        self.mark_thinking_error_failed(
+            candidate_record_id,
+            converted_error,
+            elapsed_ms,
+            captured_key_concurrent,
+            serializable_extra_data,
+        )
+        raise converted_error
+
+    async def handle_candidate_error(
+        self,
+        *,
+        exec_err: Any,
+        candidate: Any,
+        candidate_record_id: str,
+        retry_index: int,
+        max_retries_for_candidate: int,
+        affinity_key: str,
+        api_format: str,
+        global_model_id: str,
+        request_id: str | None,
+        attempt: int,
+        max_attempts: int,
+        error_classifier: Any,
+        request_body_ref: dict[str, Any] | None = None,
+    ) -> str:
+        """
+        Handle an execution error for a candidate.
+
+        Returns:
+        - "continue": retry current candidate
+        - "break": move to next candidate
+        - "raise": raise the underlying exception
+        """
+        from src.core.api_format.conversion.exceptions import FormatConversionError
+        from src.services.proxy_node.resolver import resolve_effective_proxy, resolve_proxy_info
+        from src.services.request.executor import ExecutionError
+
+        # 提前解析代理信息，写入候选记录的 extra_data（用于链路追踪展示）
+        _eff_proxy = resolve_effective_proxy(
+            getattr(candidate.provider, "proxy", None),
+            getattr(candidate.key, "proxy", None),
+        )
+        _proxy_info = resolve_proxy_info(_eff_proxy)
+        _proxy_extra: dict[str, Any] | None = {"proxy": _proxy_info} if _proxy_info else None
+
+        if not isinstance(exec_err, ExecutionError):
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type=type(exec_err).__name__,
+                error_message=str(exec_err),
+                extra_data=_proxy_extra,
+            )
+            return "break"
+
+        provider = candidate.provider
+        endpoint = candidate.endpoint
+        key = candidate.key
+
+        context = exec_err.context
+        captured_key_concurrent = context.concurrent_requests
+        elapsed_ms = context.elapsed_ms
+        cause = exec_err.cause
+
+        has_retry_left = retry_index < (max_retries_for_candidate - 1)
+
+        if isinstance(cause, ConcurrencyLimitError):
+            rpm_current = context.rpm_current
+            if rpm_current is None:
+                rpm_current = captured_key_concurrent
+
+            rpm_limit = context.rpm_limit
+            rpm_available_for_new = context.rpm_available_for_new
+            reservation_ratio = context.reservation_ratio
+            reservation_phase = context.reservation_phase or "unknown"
+            reservation_confidence = context.reservation_confidence
+            reservation_load_factor = context.reservation_load_factor
+
+            reason_code = "unknown"
+            if rpm_limit is not None and rpm_current is not None:
+                if context.is_cached_user:
+                    if rpm_current >= rpm_limit:
+                        reason_code = "total_limit"
+                else:
+                    if rpm_available_for_new is not None and rpm_current >= rpm_available_for_new:
+                        reason_code = (
+                            "reserved_for_cached" if rpm_current < rpm_limit else "total_limit"
+                        )
+                    elif rpm_current >= rpm_limit:
+                        reason_code = "total_limit"
+
+            reason_text = "并发限制"
+            if reason_code == "reserved_for_cached":
+                reason_text = "并发限制: 新用户配额已满（预留给缓存用户）"
+            elif reason_code == "total_limit":
+                reason_text = "并发限制: 总配额已满"
+
+            parts: list[str] = []
+            if rpm_current is not None:
+                parts.append(f"current={rpm_current}")
+            if rpm_limit is not None:
+                parts.append(f"limit={rpm_limit}")
+            if rpm_available_for_new is not None and not context.is_cached_user:
+                parts.append(f"new={rpm_available_for_new}")
+            if reservation_ratio is not None:
+                parts.append(f"reserve={reservation_ratio:.0%}")
+            if reservation_phase:
+                parts.append(f"phase={reservation_phase}")
+
+            skip_reason = reason_text
+            if parts:
+                skip_reason = f"{reason_text} ({', '.join(parts)})"
+
+            logger.warning(
+                "  [{}] 并发限制 (attempt={}/{}): provider={}, key={}, cached={}, reason={}, {}",
+                request_id,
+                attempt,
+                max_attempts,
+                provider.name,
+                str(key.id)[:8],
+                bool(context.is_cached_user),
+                reason_code,
+                ", ".join(parts) if parts else "N/A",
+            )
+
+            extra_data: dict[str, Any] = {
+                "concurrency_denied": True,
+                "concurrency_reason": reason_code,
+                "rpm_current": rpm_current,
+                "rpm_limit": rpm_limit,
+                "rpm_available_for_new": rpm_available_for_new,
+                "reservation_ratio": reservation_ratio,
+                "reservation_phase": reservation_phase,
+                "reservation_confidence": reservation_confidence,
+                "reservation_load_factor": reservation_load_factor,
+                "attempt": attempt,
+                "max_attempts": max_attempts,
+            }
+            extra_data = {k: v for k, v in extra_data.items() if v is not None}
+            if _proxy_extra:
+                extra_data = {**_proxy_extra, **extra_data}
+
+            try:
+                from src.core.metrics import scheduler_concurrency_denied_total
+
+                scheduler_concurrency_denied_total.labels(
+                    is_cached_user=str(bool(context.is_cached_user)).lower(),
+                    reason=reason_code,
+                    reservation_phase=str(reservation_phase or "unknown"),
+                ).inc()
+            except Exception:
+                pass
+
+            RequestCandidateService.mark_candidate_skipped(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                skip_reason=skip_reason,
+                status_code=429,
+                concurrent_requests=rpm_current,
+                extra_data=extra_data,
+            )
+            return "break"
+
+        if isinstance(cause, ProxyNodeUnavailableError):
+            # ProxyNode 不可用属于"配置明确指定但不可达/不可用"的情况，
+            # 在当前候选上重试通常没有意义，直接切换到下一个候选更合理。
+            node_id = cause.details.get("proxy_node_id") if cause.details else None
+            logger.warning(
+                "  [{}] 代理节点不可用 (node_id={})，切换候选: {}",
+                request_id,
+                node_id or "unknown",
+                str(cause),
+            )
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type=type(cause).__name__,
+                error_message=extract_error_message(cause),
+                latency_ms=elapsed_ms,
+                concurrent_requests=captured_key_concurrent,
+                extra_data=_proxy_extra,
+            )
+            return "break"
+
+        if isinstance(cause, EmbeddedErrorException):
+            error_message = cause.error_message or ""
+            embedded_status = cause.error_code or 200
+            if error_classifier.is_client_error(error_message):
+                logger.warning(
+                    "  [{}] 嵌入式客户端错误，继续转移: {}",
+                    request_id,
+                    error_message[:200],
+                )
+                RequestCandidateService.mark_candidate_failed(
+                    db=self.db,
+                    candidate_id=candidate_record_id,
+                    error_type="UpstreamClientException",
+                    error_message=error_message,
+                    status_code=embedded_status,
+                    latency_ms=elapsed_ms,
+                    concurrent_requests=captured_key_concurrent,
+                    extra_data=_proxy_extra,
+                )
+                return "break"
+
+            logger.warning(
+                "  [{}] 嵌入式服务端错误，尝试重试: {}",
+                request_id,
+                error_message[:200],
+            )
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type="EmbeddedErrorException",
+                error_message=error_message,
+                status_code=embedded_status,
+                latency_ms=elapsed_ms,
+                concurrent_requests=captured_key_concurrent,
+                extra_data=_proxy_extra,
+            )
+            return "continue" if has_retry_left else "break"
+
+        if isinstance(cause, httpx.HTTPStatusError):
+            status_code = cause.response.status_code
+            extra_data = await error_classifier.handle_http_error(
+                http_error=cause,
+                provider=provider,
+                endpoint=endpoint,
+                key=key,
+                affinity_key=affinity_key,
+                api_format=api_format,
+                global_model_id=global_model_id,
+                request_id=request_id,
+                captured_key_concurrent=captured_key_concurrent,
+                elapsed_ms=elapsed_ms,
+                max_attempts=max_attempts,
+                attempt=attempt,
+            )
+
+            # Account Pool: apply health policy (cooldown/disable).
+            await self._pool_ops.pool_on_error(provider, key, status_code, cause)
+
+            converted_error = extra_data.get("converted_error")
+            serializable_extra_data = {
+                k: v for k, v in extra_data.items() if k != "converted_error"
+            }
+            if _proxy_info:
+                serializable_extra_data["proxy"] = _proxy_info
+
+            if isinstance(converted_error, ThinkingSignatureException):
+                action = self.handle_thinking_signature_error(
+                    converted_error=converted_error,
+                    provider_type=str(getattr(provider, "provider_type", "") or "").lower(),
+                    model_name=str(global_model_id or ""),
+                    request_id=request_id,
+                    candidate_record_id=candidate_record_id,
+                    elapsed_ms=elapsed_ms,
+                    captured_key_concurrent=captured_key_concurrent,
+                    serializable_extra_data=serializable_extra_data,
+                    request_body_ref=request_body_ref,
+                )
+                if action == "continue":
+                    return "continue"
+
+            if isinstance(converted_error, UpstreamClientException):
+                logger.warning(
+                    "  [{}] 客户端请求错误，继续转移: {}",
+                    request_id,
+                    str(converted_error.message),
+                )
+                RequestCandidateService.mark_candidate_failed(
+                    db=self.db,
+                    candidate_id=candidate_record_id,
+                    error_type="UpstreamClientException",
+                    error_message=converted_error.message,
+                    status_code=status_code,
+                    latency_ms=elapsed_ms,
+                    concurrent_requests=captured_key_concurrent,
+                    extra_data=serializable_extra_data,
+                )
+                return "break"
+
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type="HTTPStatusError",
+                error_message=extract_error_message(cause, status_code),
+                status_code=status_code,
+                latency_ms=elapsed_ms,
+                concurrent_requests=captured_key_concurrent,
+                extra_data=serializable_extra_data,
+            )
+            return "continue" if has_retry_left else "break"
+
+        if isinstance(cause, error_classifier.RETRIABLE_ERRORS):
+            await error_classifier.handle_retriable_error(
+                error=cause,
+                provider=provider,
+                endpoint=endpoint,
+                key=key,
+                affinity_key=affinity_key,
+                api_format=api_format,
+                global_model_id=global_model_id,
+                captured_key_concurrent=captured_key_concurrent,
+                elapsed_ms=elapsed_ms,
+                request_id=request_id,
+                attempt=attempt,
+                max_attempts=max_attempts,
+            )
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type=type(cause).__name__,
+                error_message=extract_error_message(cause),
+                latency_ms=elapsed_ms,
+                concurrent_requests=captured_key_concurrent,
+                extra_data=_proxy_extra,
+            )
+            return "continue" if has_retry_left else "break"
+
+        if isinstance(cause, FormatConversionError):
+            logger.warning("  [{}] 格式转换失败，切换候选: {}", request_id, str(cause))
+            RequestCandidateService.mark_candidate_failed(
+                db=self.db,
+                candidate_id=candidate_record_id,
+                error_type="FormatConversionError",
+                error_message=str(cause),
+                latency_ms=elapsed_ms,
+                concurrent_requests=captured_key_concurrent,
+                extra_data=_proxy_extra,
+            )
+            return "break"
+
+        RequestCandidateService.mark_candidate_failed(
+            db=self.db,
+            candidate_id=candidate_record_id,
+            error_type=type(cause).__name__,
+            error_message=extract_error_message(cause),
+            latency_ms=elapsed_ms,
+            concurrent_requests=captured_key_concurrent,
+            extra_data=_proxy_extra,
+        )
+        return "break"

src/services/task/execute/exception_classification.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from enum import Enum
+from typing import Any
+
+
+class CandidateErrorAction(str, Enum):
+    """同步执行中，候选错误处理后的标准动作。"""
+
+    RETRY_CURRENT = "retry_current"
+    NEXT_CANDIDATE = "next_candidate"
+    RAISE_ERROR = "raise_error"
+
+
+def classify_candidate_error_action(action: Any) -> CandidateErrorAction:
+    """将 error_handler 的字符串动作分类为可控枚举。"""
+    action_norm = str(action or "").strip().lower()
+    if action_norm == "continue":
+        return CandidateErrorAction.RETRY_CURRENT
+    if action_norm == "raise":
+        return CandidateErrorAction.RAISE_ERROR
+    if action_norm == "break":
+        return CandidateErrorAction.NEXT_CANDIDATE
+    # Fail-safe：未知动作默认切到下一个候选，避免卡死在当前候选。
+    return CandidateErrorAction.NEXT_CANDIDATE

src/services/task/execute/failure.py

@@ -0,0 +1,107 @@
+from __future__ import annotations
+
+from typing import Any
+
+import httpx
+
+from src.core.exceptions import ProviderNotAvailableException
+from src.core.logger import logger
+from src.services.request.result import RequestMetadata
+
+
+class TaskFailureOperationsService:
+    """任务失败收敛相关操作（异常元数据与统一抛错）。"""
+
+    @staticmethod
+    def attach_metadata_to_error(
+        error: Exception | None,
+        candidate: Any | None,
+        model_name: str,
+        api_format: str,
+    ) -> None:
+        """Attach candidate metadata onto exception for usage recording."""
+        if not error or not candidate:
+            return
+
+        existing_metadata = getattr(error, "request_metadata", None)
+        if existing_metadata and getattr(existing_metadata, "api_format", None):
+            return
+
+        metadata = RequestMetadata(
+            provider_request_headers=(
+                getattr(existing_metadata, "provider_request_headers", {})
+                if existing_metadata
+                else {}
+            ),
+            provider=getattr(existing_metadata, "provider", None) or str(candidate.provider.name),
+            model=getattr(existing_metadata, "model", None) or model_name,
+            provider_id=getattr(existing_metadata, "provider_id", None)
+            or str(candidate.provider.id),
+            provider_endpoint_id=(
+                getattr(existing_metadata, "provider_endpoint_id", None)
+                or str(candidate.endpoint.id)
+            ),
+            provider_api_key_id=(
+                getattr(existing_metadata, "provider_api_key_id", None) or str(candidate.key.id)
+            ),
+            api_format=api_format,
+        )
+        setattr(error, "request_metadata", metadata)
+
+    @staticmethod
+    def raise_all_failed_exception(
+        request_id: str | None,
+        max_attempts: int,
+        last_candidate: Any | None,
+        model_name: str,
+        api_format: str,
+        last_error: Exception | None = None,
+    ) -> None:
+        """Raise a unified 'all candidates failed' exception."""
+        logger.error("  [{}] 所有 {} 个组合均失败", request_id, max_attempts)
+
+        request_metadata = None
+        if last_candidate:
+            request_metadata = {
+                "provider": last_candidate.provider.name,
+                "model": model_name,
+                "provider_id": str(last_candidate.provider.id),
+                "provider_endpoint_id": str(last_candidate.endpoint.id),
+                "provider_api_key_id": str(last_candidate.key.id),
+                "api_format": api_format,
+            }
+
+        upstream_status: int | None = None
+        upstream_response: str | None = None
+        if last_error:
+            if isinstance(last_error, httpx.HTTPStatusError):
+                upstream_status = last_error.response.status_code
+                upstream_response = getattr(last_error, "upstream_response", None)
+                if not upstream_response:
+                    try:
+                        upstream_response = last_error.response.text
+                    except Exception:
+                        pass
+            else:
+                upstream_status = getattr(last_error, "upstream_status", None)
+                upstream_response = getattr(last_error, "upstream_response", None)
+
+            if (
+                not upstream_response
+                or not upstream_response.strip()
+                or upstream_response.startswith("Unable to read")
+            ):
+                upstream_response = str(last_error)
+
+        friendly_message = "服务暂时不可用，请稍后重试"
+        if last_error:
+            last_error_message = getattr(last_error, "message", None)
+            if last_error_message and isinstance(last_error_message, str):
+                friendly_message = last_error_message
+
+        raise ProviderNotAvailableException(
+            friendly_message,
+            request_metadata=request_metadata,
+            upstream_status=upstream_status,
+            upstream_response=upstream_response,
+        )

src/services/task/execute/pool.py

@@ -0,0 +1,222 @@
+from __future__ import annotations
+
+from typing import Any
+
+from src.core.logger import logger
+
+
+class TaskPoolOperationsService:
+    """任务池化相关操作（重排、展开、健康回写）。"""
+
+    def extract_session_uuid(
+        self,
+        provider_type: str,
+        request_body: dict[str, Any] | None,
+    ) -> str | None:
+        """Extract a session UUID from the request body (provider-type aware)."""
+        if not isinstance(request_body, dict):
+            return None
+        from src.services.provider.pool.hooks import get_pool_hook
+
+        hook = get_pool_hook(provider_type)
+        if hook is not None:
+            return hook.extract_session_uuid(request_body)
+        return None
+
+    async def apply_pool_reorder(
+        self,
+        candidates: list[Any],
+        request_body: dict[str, Any] | None,
+    ) -> tuple[list[Any], list[Any]]:
+        """Apply pool key ordering for PoolCandidate objects."""
+        if not candidates:
+            return candidates, []
+
+        pool_traces: list[Any] = []
+
+        try:
+            from src.services.provider.pool.config import parse_pool_config
+            from src.services.provider.pool.manager import PoolManager
+            from src.services.scheduling.schemas import PoolCandidate
+
+            for candidate in candidates:
+                if not isinstance(candidate, PoolCandidate):
+                    continue
+
+                provider = candidate.provider
+                provider_id = str(getattr(provider, "id", "") or "")
+                if not provider_id:
+                    continue
+
+                pool_cfg = candidate.pool_config or parse_pool_config(
+                    getattr(provider, "config", None)
+                )
+                if pool_cfg is None:
+                    continue
+                candidate.pool_config = pool_cfg
+
+                provider_type = str(getattr(provider, "provider_type", "") or "")
+                session_uuid = self.extract_session_uuid(provider_type, request_body)
+                manager = PoolManager(provider_id, pool_cfg)
+
+                candidate_keys = list(candidate.pool_keys or [])
+                if not candidate_keys and getattr(candidate, "key", None) is not None:
+                    candidate_keys = [candidate.key]
+
+                ordered_keys, trace = await manager.select_pool_keys(session_uuid, candidate_keys)
+                candidate.pool_keys = ordered_keys
+
+                selected_key_index = 0
+                selected_key = None
+                for idx, pool_key in enumerate(ordered_keys):
+                    if not bool(getattr(pool_key, "_pool_skipped", False)):
+                        selected_key = pool_key
+                        selected_key_index = idx
+                        break
+
+                if selected_key is not None:
+                    candidate.key = selected_key
+                    candidate._pool_key_index = selected_key_index
+                    candidate.mapping_matched_model = getattr(
+                        selected_key, "_pool_mapping_matched_model", None
+                    )
+                    candidate.is_skipped = False
+                    candidate.skip_reason = None
+                else:
+                    candidate.is_skipped = True
+                    candidate.skip_reason = "pool: all keys unavailable"
+
+                if trace is not None:
+                    pool_traces.append(trace)
+
+            return candidates, pool_traces
+        except Exception:
+            logger.opt(exception=True).debug("Pool reorder failed, using original order")
+            return candidates, []
+
+    @staticmethod
+    def expand_pool_candidates_for_async_submit(candidates: list[Any]) -> list[Any]:
+        """Expand PoolCandidate to key-level candidates for async submit traversal."""
+        from src.services.scheduling.schemas import PoolCandidate, ProviderCandidate
+
+        expanded: list[Any] = []
+        for candidate in candidates:
+            if not isinstance(candidate, PoolCandidate):
+                expanded.append(candidate)
+                continue
+
+            pool_keys = list(candidate.pool_keys or [])
+            if not pool_keys:
+                expanded.append(candidate)
+                continue
+
+            for key_index, pool_key in enumerate(pool_keys):
+                key_skipped = bool(getattr(pool_key, "_pool_skipped", False))
+                key_skip_reason = (
+                    str(getattr(pool_key, "_pool_skip_reason", "") or "") or candidate.skip_reason
+                )
+                key_extra = (
+                    getattr(pool_key, "_pool_extra_data", None)
+                    if isinstance(getattr(pool_key, "_pool_extra_data", None), dict)
+                    else {}
+                )
+
+                key_candidate = ProviderCandidate(
+                    provider=candidate.provider,
+                    endpoint=candidate.endpoint,
+                    key=pool_key,
+                    is_cached=candidate.is_cached,
+                    is_skipped=bool(candidate.is_skipped) or key_skipped,
+                    skip_reason=(
+                        key_skip_reason if (bool(candidate.is_skipped) or key_skipped) else None
+                    ),
+                    mapping_matched_model=getattr(pool_key, "_pool_mapping_matched_model", None)
+                    or candidate.mapping_matched_model,
+                    needs_conversion=candidate.needs_conversion,
+                    provider_api_format=candidate.provider_api_format,
+                    output_limit=candidate.output_limit,
+                    capability_miss_count=candidate.capability_miss_count,
+                )
+                setattr(
+                    key_candidate,
+                    "_pool_extra_data",
+                    {
+                        "pool_group_id": str(candidate.provider.id),
+                        "pool_key_index": key_index,
+                        **key_extra,
+                    },
+                )
+                expanded.append(key_candidate)
+
+        return expanded
+
+    async def pool_on_success(
+        self,
+        candidate: Any,
+        request_body: dict[str, Any] | None,
+    ) -> None:
+        """Notify the pool manager about a successful request (sticky + LRU)."""
+        try:
+            from src.services.provider.pool.config import parse_pool_config
+            from src.services.provider.pool.manager import PoolManager
+
+            provider = candidate.provider
+            provider_config = getattr(provider, "config", None)
+            pool_cfg = parse_pool_config(provider_config)
+            if pool_cfg is None:
+                return
+
+            provider_id = str(getattr(provider, "id", "") or "")
+            key_id = str(getattr(candidate.key, "id", "") or "")
+            if not provider_id or not key_id:
+                return
+
+            provider_type = str(getattr(provider, "provider_type", "") or "")
+            session_uuid = self.extract_session_uuid(provider_type, request_body)
+
+            mgr = PoolManager(provider_id, pool_cfg)
+            await mgr.on_request_success(
+                session_uuid=session_uuid,
+                key_id=key_id,
+            )
+        except Exception:
+            logger.opt(exception=True).debug("Pool on_request_success failed (non-blocking)")
+
+    @staticmethod
+    async def pool_on_error(
+        provider: Any,
+        key: Any,
+        status_code: int,
+        cause: Any,
+    ) -> None:
+        """Notify the pool manager about an upstream error (health policy)."""
+        try:
+            from src.services.provider.pool.config import parse_pool_config
+            from src.services.provider.pool.health_policy import apply_health_policy
+
+            pool_cfg = parse_pool_config(getattr(provider, "config", None))
+            if pool_cfg is None:
+                return
+
+            error_text = ""
+            resp_headers: dict[str, str] = {}
+            if getattr(cause, "response", None) is not None:
+                try:
+                    error_text = (cause.response.text or "")[:4000]
+                except Exception:
+                    pass
+                try:
+                    resp_headers = dict(cause.response.headers)
+                except Exception:
+                    pass
+
+            await apply_health_policy(
+                provider_id=str(provider.id),
+                key_id=str(key.id),
+                status_code=status_code,
+                error_body=error_text,
+                response_headers=resp_headers,
+                config=pool_cfg,
+            )
+        except Exception:
+            pass

src/services/task/execute/state_transition.py

@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING, Any
+
+from src.services.candidate.policy import FailoverAction
+from src.services.task.execute.exception_classification import CandidateErrorAction
+
+if TYPE_CHECKING:
+    from src.services.task.execute.failure import TaskFailureOperationsService
+
+
+@dataclass(slots=True)
+class ExecutionErrorTransition:
+    """执行异常后的状态流转决策。"""
+
+    failover_action: FailoverAction
+    max_retries: int | None = None
+
+    def as_failover_tuple(self) -> tuple[FailoverAction, int | None]:
+        return (self.failover_action, self.max_retries)
+
+
+@dataclass(slots=True)
+class SyncExecutionState:
+    """同步执行阶段状态容器（候选上下文 + 异常上下文）。"""
+
+    candidate_record_map: dict[tuple[int, int], str]
+    request_body_ref: dict[str, Any] | None
+    last_error: Exception | None = None
+    last_candidate: Any | None = None
+    _rectify_flag_key: str = field(default="_rectified_this_turn", repr=False)
+
+    def touch_candidate(self, candidate: Any) -> None:
+        self.last_candidate = candidate
+
+    def track_execution_error(self, *, exec_err: Any, candidate: Any) -> None:
+        self.last_candidate = candidate
+        cause = getattr(exec_err, "cause", None)
+        self.last_error = cause if isinstance(cause, Exception) else None
+
+    def resolve_candidate_record_id(self, *, candidate_index: int, record_id: str | None) -> str:
+        if record_id:
+            return str(record_id)
+        return str(self.candidate_record_map.get((candidate_index, 0), "") or "")
+
+    def consume_rectify_retry_extension(
+        self, *, max_retries_for_candidate: int, retry_index: int
+    ) -> int | None:
+        if not self.request_body_ref:
+            return None
+        if not self.request_body_ref.get(self._rectify_flag_key, False):
+            return None
+
+        self.request_body_ref[self._rectify_flag_key] = False
+        return max(max_retries_for_candidate, retry_index + 2)
+
+    def raise_classified_error(
+        self,
+        *,
+        fallback_error: Any,
+        failure_ops: TaskFailureOperationsService,
+        model_name: str,
+        api_format: str,
+    ) -> None:
+        if self.last_error is not None:
+            failure_ops.attach_metadata_to_error(
+                self.last_error,
+                self.last_candidate,
+                model_name,
+                api_format,
+            )
+            raise self.last_error
+
+        if isinstance(fallback_error, Exception):
+            raise fallback_error
+
+        raise RuntimeError("execution_error_handler requested raise without exception context")
+
+
+def resolve_execution_error_transition(
+    *,
+    action: CandidateErrorAction,
+    state: SyncExecutionState,
+    max_retries_for_candidate: int,
+    retry_index: int,
+) -> ExecutionErrorTransition:
+    """根据异常动作分类，返回 FailoverEngine 可消费的状态流转结果。"""
+    if action == CandidateErrorAction.RETRY_CURRENT:
+        return ExecutionErrorTransition(
+            failover_action=FailoverAction.RETRY,
+            max_retries=state.consume_rectify_retry_extension(
+                max_retries_for_candidate=max_retries_for_candidate,
+                retry_index=retry_index,
+            ),
+        )
+
+    return ExecutionErrorTransition(
+        failover_action=FailoverAction.CONTINUE,
+        max_retries=None,
+    )

src/services/task/execute/sync_execute.py

@@ -0,0 +1,370 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Any
+from uuid import uuid4
+
+from src.core.logger import logger
+from src.models.database import ApiKey, User
+from src.services.candidate.failover import FailoverEngine
+from src.services.candidate.policy import FailoverAction, RetryPolicy, SkipPolicy
+from src.services.candidate.resolver import CandidateResolver
+from src.services.orchestration.error_classifier import ErrorClassifier
+from src.services.orchestration.request_dispatcher import RequestDispatcher
+from src.services.provider.format import normalize_endpoint_signature
+from src.services.request.candidate import RequestCandidateService
+from src.services.scheduling.aware_scheduler import (
+    CacheAwareScheduler,
+    get_cache_aware_scheduler,
+)
+from src.services.system.config import SystemConfigService
+from src.services.task.core.protocol import AttemptKind, AttemptResult
+from src.services.task.core.schema import ExecutionResult
+from src.services.task.execute.error_handler import TaskErrorOperationsService
+from src.services.task.execute.exception_classification import (
+    CandidateErrorAction,
+    classify_candidate_error_action,
+)
+from src.services.task.execute.failure import TaskFailureOperationsService
+from src.services.task.execute.pool import TaskPoolOperationsService
+from src.services.task.execute.state_transition import (
+    SyncExecutionState,
+    resolve_execution_error_transition,
+)
+from src.services.usage.service import UsageService
+
+
+class SyncTaskExecutionService:
+    """同步任务执行服务（候选遍历 + 错误处理 + 结果聚合）。"""
+
+    def __init__(
+        self,
+        db: Any,
+        redis_client: Any | None,
+        *,
+        recorder: Any,
+        pool_ops: TaskPoolOperationsService,
+        error_ops: TaskErrorOperationsService,
+        failure_ops: TaskFailureOperationsService,
+    ) -> None:
+        self.db = db
+        self.redis = redis_client
+        self._recorder = recorder
+        self._pool_ops = pool_ops
+        self._error_ops = error_ops
+        self._failure_ops = failure_ops
+
+    async def execute_sync_unified(
+        self,
+        *,
+        api_format: str,
+        model_name: str,
+        user_api_key: ApiKey,
+        request_func: Callable[..., Any],
+        request_id: str | None,
+        is_stream: bool,
+        capability_requirements: dict[str, bool] | None,
+        preferred_key_ids: list[str] | None,
+        request_body_ref: dict[str, Any] | None,
+        request_headers: dict[str, Any] | None,
+        request_body: dict[str, Any] | None,
+    ) -> ExecutionResult:
+        """
+        Unified candidate traversal loop for SYNC.
+
+        This intentionally reuses existing components for parity:
+        - CandidateResolver fetch + record creation
+        - RequestDispatcher execution
+        - Error classification/rectify logic ported from the previous SYNC implementation
+        """
+        from src.services.rate_limit.adaptive_rpm import get_adaptive_rpm_manager
+        from src.services.rate_limit.concurrency_manager import get_concurrency_manager
+        from src.services.request.executor import RequestExecutor
+
+        if not request_id:
+            request_id = str(uuid4())
+
+        # Build execution components (mirrors pre-Phase-3 initialization)
+        priority_mode = SystemConfigService.get_config(
+            self.db,
+            "provider_priority_mode",
+            CacheAwareScheduler.PRIORITY_MODE_PROVIDER,
+        )
+        scheduling_mode = SystemConfigService.get_config(
+            self.db,
+            "scheduling_mode",
+            CacheAwareScheduler.SCHEDULING_MODE_CACHE_AFFINITY,
+        )
+        cache_scheduler = await get_cache_aware_scheduler(
+            self.redis,
+            priority_mode=priority_mode,
+            scheduling_mode=scheduling_mode,
+        )
+        # Ensure cache_scheduler inner state is ready
+        await cache_scheduler._ensure_initialized()
+
+        concurrency_manager = await get_concurrency_manager()
+        adaptive_manager = get_adaptive_rpm_manager()
+        request_executor = RequestExecutor(
+            db=self.db,
+            concurrency_manager=concurrency_manager,
+            adaptive_manager=adaptive_manager,
+        )
+        candidate_resolver = CandidateResolver(
+            db=self.db,
+            cache_scheduler=cache_scheduler,
+        )
+        error_classifier = ErrorClassifier(
+            db=self.db,
+            cache_scheduler=cache_scheduler,
+            adaptive_manager=adaptive_manager,
+        )
+        request_dispatcher = RequestDispatcher(
+            db=self.db,
+            request_executor=request_executor,
+            cache_scheduler=cache_scheduler,
+        )
+
+        affinity_key = str(user_api_key.id)
+        user_id = str(user_api_key.user_id)
+        api_format_norm = normalize_endpoint_signature(api_format)
+
+        # Keep pending usage creation behavior consistent with previous behavior
+        try:
+            user = self.db.query(User).filter(User.id == user_api_key.user_id).first()
+            UsageService.create_pending_usage(
+                db=self.db,
+                request_id=request_id,
+                user=user,
+                api_key=user_api_key,
+                model=model_name,
+                is_stream=is_stream,
+                api_format=api_format_norm,
+                request_headers=request_headers,
+                request_body=request_body,
+            )
+        except Exception as exc:
+            logger.warning("创建 pending 使用记录失败: {}", str(exc))
+
+        all_candidates, global_model_id = await candidate_resolver.fetch_candidates(
+            api_format=api_format_norm,
+            model_name=model_name,
+            affinity_key=affinity_key,
+            user_api_key=user_api_key,
+            request_id=request_id,
+            is_stream=is_stream,
+            capability_requirements=capability_requirements,
+            preferred_key_ids=preferred_key_ids,
+            request_body=request_body,
+        )
+
+        # Account Pool: reorder candidates for claude_code providers.
+        all_candidates, pool_traces = await self._pool_ops.apply_pool_reorder(
+            all_candidates, request_body=request_body
+        )
+
+        candidate_record_map = candidate_resolver.create_candidate_records(
+            all_candidates=all_candidates,
+            request_id=request_id,
+            user_id=user_id,
+            user_api_key=user_api_key,
+            required_capabilities=capability_requirements,
+        )
+
+        max_attempts = candidate_resolver.count_total_attempts(all_candidates)
+        # Keep behavior consistent with previous behavior: last_candidate is updated even if skipped.
+        execution_state = SyncExecutionState(
+            candidate_record_map=candidate_record_map,
+            request_body_ref=request_body_ref,
+            last_candidate=all_candidates[-1] if all_candidates else None,
+        )
+
+        async def _attempt(candidate: Any) -> AttemptResult:
+            execution_state.touch_candidate(candidate)
+
+            candidate_index = int(getattr(candidate, "_utf_candidate_index", -1))
+            retry_index = int(getattr(candidate, "_utf_retry_index", 0))
+            candidate_record_id = str(getattr(candidate, "_utf_candidate_record_id", "") or "")
+            attempt_counter = int(getattr(candidate, "_utf_attempt_count", 0))
+            max_attempts_local = int(getattr(candidate, "_utf_max_attempts", max_attempts))
+
+            # Safety net: if record_id missing, create an "available" record on-demand.
+            if not candidate_record_id:
+                from src.services.scheduling.schemas import PoolCandidate
+
+                pool_extra = (
+                    getattr(candidate.key, "_pool_extra_data", None)
+                    if isinstance(getattr(candidate.key, "_pool_extra_data", None), dict)
+                    else {}
+                )
+                extra_data: dict[str, Any] = {
+                    "needs_conversion": bool(getattr(candidate, "needs_conversion", False)),
+                    "provider_api_format": getattr(candidate, "provider_api_format", None) or None,
+                    "mapping_matched_model": getattr(candidate, "mapping_matched_model", None)
+                    or None,
+                    **pool_extra,
+                }
+                if isinstance(candidate, PoolCandidate):
+                    extra_data["pool_group_id"] = str(candidate.provider.id)
+                    extra_data["pool_key_index"] = int(
+                        getattr(candidate, "_pool_key_index", 0) or 0
+                    )
+                created = RequestCandidateService.create_candidate(
+                    db=self.db,
+                    request_id=request_id,
+                    candidate_index=candidate_index,
+                    retry_index=retry_index,
+                    user_id=user_id,
+                    api_key_id=str(user_api_key.id),
+                    provider_id=str(candidate.provider.id),
+                    endpoint_id=str(candidate.endpoint.id),
+                    key_id=str(candidate.key.id),
+                    status="available",
+                    is_cached=bool(getattr(candidate, "is_cached", False)),
+                    extra_data=extra_data,
+                )
+                candidate_record_id = str(created.id)
+                execution_state.candidate_record_map[(candidate_index, retry_index)] = (
+                    candidate_record_id
+                )
+
+            response, _provider_name, attempt_id, _provider_id, _endpoint_id, _key_id = (
+                await request_dispatcher.dispatch(
+                    candidate=candidate,
+                    candidate_index=candidate_index,
+                    retry_index=retry_index,
+                    candidate_record_id=candidate_record_id,
+                    user_api_key=user_api_key,
+                    request_func=request_func,
+                    request_id=request_id,
+                    api_format=api_format_norm,
+                    model_name=model_name,
+                    affinity_key=affinity_key,
+                    global_model_id=global_model_id,
+                    attempt_counter=attempt_counter,
+                    max_attempts=max_attempts_local,
+                    is_stream=is_stream,
+                )
+            )
+            _ = (attempt_id, _provider_name, _provider_id, _endpoint_id, _key_id)
+
+            # Account Pool: on success, update sticky binding + LRU.
+            await self._pool_ops.pool_on_success(candidate, request_body)
+
+            if is_stream:
+                return AttemptResult(
+                    kind=AttemptKind.STREAM,
+                    http_status=200,
+                    http_headers={},
+                    stream_iterator=response,
+                )
+            return AttemptResult(
+                kind=AttemptKind.SYNC_RESPONSE,
+                http_status=200,
+                http_headers={},
+                response_body=response,
+            )
+
+        async def _handle_exec_err(
+            *,
+            exec_err: Any,
+            candidate: Any,
+            candidate_index: int,
+            retry_index: int,
+            max_retries_for_candidate: int,
+            record_id: str | None,
+            attempt_count: int,
+            max_attempts: int | None,
+        ) -> tuple[FailoverAction, int | None]:
+            execution_state.track_execution_error(exec_err=exec_err, candidate=candidate)
+            # Fall back to retry 0 record if needed (rectify may extend retries).
+            candidate_record_id = execution_state.resolve_candidate_record_id(
+                candidate_index=candidate_index,
+                record_id=record_id,
+            )
+
+            raw_action = await self._error_ops.handle_candidate_error(
+                exec_err=exec_err,
+                candidate=candidate,
+                candidate_record_id=candidate_record_id,
+                retry_index=retry_index,
+                max_retries_for_candidate=max_retries_for_candidate,
+                affinity_key=affinity_key,
+                api_format=api_format_norm,
+                global_model_id=global_model_id,
+                request_id=request_id,
+                attempt=attempt_count,
+                max_attempts=int(max_attempts or 0),
+                request_body_ref=request_body_ref,
+                error_classifier=error_classifier,
+            )
+            action = classify_candidate_error_action(raw_action)
+
+            if action == CandidateErrorAction.RAISE_ERROR:
+                execution_state.raise_classified_error(
+                    fallback_error=exec_err,
+                    failure_ops=self._failure_ops,
+                    model_name=model_name,
+                    api_format=api_format_norm,
+                )
+
+            return resolve_execution_error_transition(
+                action=action,
+                state=execution_state,
+                max_retries_for_candidate=max_retries_for_candidate,
+                retry_index=retry_index,
+            ).as_failover_tuple()
+
+        engine = FailoverEngine(
+            self.db,
+            error_classifier=error_classifier,
+            recorder=self._recorder,
+        )
+        result = await engine.execute(
+            candidates=all_candidates,
+            attempt_func=_attempt,
+            retry_policy=RetryPolicy.for_sync_task(),
+            skip_policy=SkipPolicy(),
+            request_id=request_id,
+            user_id=user_id,
+            api_key_id=str(user_api_key.id),
+            candidate_record_map=candidate_record_map,
+            max_attempts=max_attempts,
+            execution_error_handler=_handle_exec_err,
+        )
+
+        if result.success:
+            # Build pool scheduling summary from traces collected during reorder.
+            if pool_traces and result.key_id:
+                try:
+                    attempted_key_ids: set[str] = set()
+                    for ck in result.candidate_keys or []:
+                        status = str(getattr(ck, "status", "") or "").strip().lower()
+                        if status in {"", "available", "pending", "skipped", "unused"}:
+                            continue
+                        kid = getattr(ck, "key_id", None)
+                        if isinstance(kid, str) and kid:
+                            attempted_key_ids.add(kid)
+                    if not attempted_key_ids:
+                        attempted_key_ids.add(str(result.key_id))
+
+                    for pt in pool_traces:
+                        summary = pt.build_summary(
+                            result.key_id,
+                            attempted_key_ids=attempted_key_ids,
+                        )
+                        if summary:
+                            result.pool_summary = summary
+                            break
+                except Exception:
+                    pass
+            return result
+
+        self._failure_ops.raise_all_failed_exception(
+            request_id,
+            max_attempts,
+            execution_state.last_candidate,
+            model_name,
+            api_format_norm,
+            execution_state.last_error,
+        )

src/services/task/impl/__init__.py

@@ -1,7 +0,0 @@
-"""Per-task-type implementations (Phase2).
-
-Currently includes:
-- video: polling adapter
-"""
-
-__all__ = []

src/services/task/polling/task_poller.py

@@ -21,7 +21,7 @@ from src.core.api_format.conversion.internal_video import InternalVideoPollResul
 from src.core.logger import logger
 from src.database import create_session
 from src.services.system.scheduler import get_scheduler
-from src.services.task.impl.video_poller import VideoPollContext, VideoTaskPollerAdapter
+from src.services.task.video.poller_adapter import VideoPollContext, VideoTaskPollerAdapter
 
 
 @runtime_checkable

src/services/task/submit/__init__.py

@@ -0,0 +1,12 @@
+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable
+from typing import Any
+
+ApplyPoolReorderFn = Callable[
+    [list[Any], dict[str, Any] | None],
+    Awaitable[tuple[list[Any], list[Any]]],
+]
+ExpandPoolCandidatesFn = Callable[[list[Any]], list[Any]]
+
+__all__ = ["ApplyPoolReorderFn", "ExpandPoolCandidatesFn"]

src/services/task/submit/attempt.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Any
+
+import httpx
+from sqlalchemy.orm import Session
+
+from src.services.billing.rule_service import BillingRuleLookupResult
+from src.services.candidate.submit import SubmitOutcome
+from src.services.task.submit.record import AsyncSubmitRecordService
+from src.services.task.submit.response import AsyncSubmitResponseService
+
+
+class AsyncSubmitAttemptService:
+    """异步提交单候选执行编排服务。"""
+
+    def __init__(
+        self,
+        db: Session,
+        *,
+        sanitize: Callable[[str], str],
+        extract_response_text: Callable[[httpx.Response], str],
+        match_provider_failover_rule: Callable[..., str | None],
+    ) -> None:
+        self.db = db
+        self._record_ops = AsyncSubmitRecordService(db)
+        self._response_ops = AsyncSubmitResponseService(
+            db,
+            record_ops=self._record_ops,
+            sanitize=sanitize,
+            extract_response_text=extract_response_text,
+            match_provider_failover_rule=match_provider_failover_rule,
+        )
+
+    async def submit_candidate(
+        self,
+        *,
+        candidate: Any,
+        record_id: str | None,
+        candidate_info: dict[str, Any],
+        candidate_keys: list[dict[str, Any]],
+        rule_lookup: BillingRuleLookupResult | None,
+        submit_func: Any,
+        extract_external_task_id: Any,
+    ) -> tuple[SubmitOutcome | None, int | None]:
+        self._record_ops.mark_pending(record_id=record_id)
+
+        # Flush/commit BEFORE awaiting upstream submit to avoid holding DB connections.
+        if self.db.in_transaction():
+            try:
+                self.db.commit()
+            except Exception:
+                self.db.rollback()
+                raise
+
+        # Attempt submit (upstream HTTP)
+        try:
+            response: httpx.Response = await submit_func(candidate)
+        except Exception as exc:
+            return self._response_ops.handle_submit_exception(
+                record_id=record_id,
+                candidate_info=candidate_info,
+                exc=exc,
+            )
+
+        return self._response_ops.handle_submit_response(
+            candidate=candidate,
+            record_id=record_id,
+            candidate_info=candidate_info,
+            candidate_keys=candidate_keys,
+            rule_lookup=rule_lookup,
+            response=response,
+            extract_external_task_id=extract_external_task_id,
+        )

src/services/task/submit/execute.py

@@ -0,0 +1,104 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Any
+
+import httpx
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.services.candidate.submit import AllCandidatesFailedError, SubmitOutcome
+from src.services.task.submit.attempt import AsyncSubmitAttemptService
+from src.services.task.submit.filter import AsyncSubmitFilterService
+
+
+class AsyncSubmitExecutionService:
+    """异步提交候选执行编排服务。"""
+
+    def __init__(
+        self,
+        db: Session,
+        *,
+        sanitize: Callable[[str], str],
+        extract_response_text: Callable[[httpx.Response], str],
+        match_provider_failover_rule: Callable[..., str | None],
+    ) -> None:
+        self.db = db
+        self._filter_ops = AsyncSubmitFilterService(db)
+        self._attempt_ops = AsyncSubmitAttemptService(
+            db,
+            sanitize=sanitize,
+            extract_response_text=extract_response_text,
+            match_provider_failover_rule=match_provider_failover_rule,
+        )
+
+    async def execute_submit_loop(
+        self,
+        *,
+        candidates: list[Any],
+        record_map: dict[tuple[int, int], str],
+        task_type: str,
+        model_name: str,
+        submit_func: Any,
+        extract_external_task_id: Any,
+        supported_auth_types: set[str] | None,
+        allow_format_conversion: bool,
+    ) -> SubmitOutcome:
+        candidate_keys: list[dict[str, Any]] = []
+        eligible_count = 0
+        last_status_code: int | None = None
+
+        for idx, cand in enumerate(candidates):
+            candidate_info = self._filter_ops.build_candidate_info(idx=idx, candidate=cand)
+            candidate_keys.append(candidate_info)
+
+            attempt_plan = self._filter_ops.prepare_candidate_for_attempt(
+                idx=idx,
+                candidate=cand,
+                record_map=record_map,
+                candidate_info=candidate_info,
+                task_type=task_type,
+                model_name=model_name,
+                supported_auth_types=supported_auth_types,
+                allow_format_conversion=allow_format_conversion,
+            )
+            if attempt_plan is None:
+                continue
+
+            eligible_count += 1
+            outcome, status_code = await self._attempt_ops.submit_candidate(
+                candidate=cand,
+                record_id=attempt_plan.record_id,
+                candidate_info=candidate_info,
+                candidate_keys=candidate_keys,
+                rule_lookup=attempt_plan.rule_lookup,
+                submit_func=submit_func,
+                extract_external_task_id=extract_external_task_id,
+            )
+
+            if status_code is not None:
+                last_status_code = status_code
+            if outcome is not None:
+                return outcome
+
+        # Persist candidate records before raising.
+        try:
+            self.db.commit()
+        except Exception:
+            self.db.rollback()
+
+        if eligible_count == 0:
+            reason = "no_eligible_candidates"
+            if config.billing_require_rule:
+                reason = "no_candidate_with_billing_rule"
+            raise AllCandidatesFailedError(
+                reason=reason,
+                candidate_keys=candidate_keys,
+                last_status_code=last_status_code,
+            )
+
+        raise AllCandidatesFailedError(
+            reason="all_candidates_failed",
+            candidate_keys=candidate_keys,
+            last_status_code=last_status_code,
+        )

src/services/task/submit/filter.py

@@ -0,0 +1,137 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+from sqlalchemy import update
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.models.database import RequestCandidate
+from src.services.billing.rule_service import BillingRuleLookupResult, BillingRuleService
+from src.services.system.config import SystemConfigService
+
+
+@dataclass(slots=True)
+class CandidateAttemptPlan:
+    """候选尝试计划（通过过滤后可进入提交阶段）。"""
+
+    record_id: str | None
+    rule_lookup: BillingRuleLookupResult | None
+
+
+class AsyncSubmitFilterService:
+    """异步提交候选过滤服务。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    @staticmethod
+    def build_candidate_info(*, idx: int, candidate: Any) -> dict[str, Any]:
+        auth_type = getattr(candidate.key, "auth_type", "api_key") or "api_key"
+        return {
+            "index": idx,
+            "provider_id": candidate.provider.id,
+            "provider_name": candidate.provider.name,
+            "endpoint_id": candidate.endpoint.id,
+            "key_id": candidate.key.id,
+            "key_name": getattr(candidate.key, "name", None),
+            "auth_type": auth_type,
+            "priority": getattr(candidate.key, "priority", 0) or 0,
+            "is_cached": bool(getattr(candidate, "is_cached", False)),
+        }
+
+    def prepare_candidate_for_attempt(
+        self,
+        *,
+        idx: int,
+        candidate: Any,
+        record_map: dict[tuple[int, int], str],
+        candidate_info: dict[str, Any],
+        task_type: str,
+        model_name: str,
+        supported_auth_types: set[str] | None,
+        allow_format_conversion: bool,
+    ) -> CandidateAttemptPlan | None:
+        record_id = record_map.get((idx, 0))
+        auth_type = candidate_info.get("auth_type", "api_key")
+
+        # Scheduler marked skip
+        if getattr(candidate, "is_skipped", False):
+            skip_reason = getattr(candidate, "skip_reason", None) or "skipped"
+            self._mark_skip(
+                record_id=record_id, candidate_info=candidate_info, skip_reason=skip_reason
+            )
+            return None
+
+        # Format conversion checks
+        needs_conversion = bool(getattr(candidate, "needs_conversion", False))
+        if needs_conversion:
+            # 1. handler-level switch
+            if not allow_format_conversion:
+                self._mark_skip(
+                    record_id=record_id,
+                    candidate_info=candidate_info,
+                    skip_reason="format_conversion_not_supported",
+                )
+                return None
+
+            # 2. global switch (from database config)
+            if not SystemConfigService.is_format_conversion_enabled(self.db):
+                self._mark_skip(
+                    record_id=record_id,
+                    candidate_info=candidate_info,
+                    skip_reason="format_conversion_disabled",
+                    extra_info={"format_conversion_enabled": False},
+                )
+                return None
+
+        # auth_type filter
+        if supported_auth_types is not None and auth_type not in supported_auth_types:
+            self._mark_skip(
+                record_id=record_id,
+                candidate_info=candidate_info,
+                skip_reason=f"unsupported_auth_type:{auth_type}",
+            )
+            return None
+
+        # billing rule filter
+        rule_lookup: BillingRuleLookupResult | None = None
+        has_billing_rule = True
+        if config.billing_require_rule:
+            rule_lookup = BillingRuleService.find_rule(
+                self.db,
+                provider_id=candidate.provider.id,
+                model_name=model_name,
+                task_type=task_type,
+            )
+            has_billing_rule = rule_lookup is not None
+            if not has_billing_rule:
+                self._mark_skip(
+                    record_id=record_id,
+                    candidate_info=candidate_info,
+                    skip_reason="billing_rule_missing",
+                    extra_info={"has_billing_rule": False},
+                )
+                return None
+        candidate_info["has_billing_rule"] = has_billing_rule
+
+        return CandidateAttemptPlan(record_id=record_id, rule_lookup=rule_lookup)
+
+    def _mark_skip(
+        self,
+        *,
+        record_id: str | None,
+        candidate_info: dict[str, Any],
+        skip_reason: str,
+        extra_info: dict[str, Any] | None = None,
+    ) -> None:
+        candidate_info.update({"skipped": True, "skip_reason": skip_reason})
+        if extra_info:
+            candidate_info.update(extra_info)
+        if record_id:
+            self.db.execute(
+                update(RequestCandidate)
+                .where(RequestCandidate.id == record_id)
+                .values(status="skipped", skip_reason=skip_reason)
+            )

src/services/task/submit/outcome_builder.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import Any
+
+import httpx
+
+from src.services.billing.rule_service import BillingRuleLookupResult
+from src.services.candidate.submit import SubmitOutcome
+
+
+@dataclass(slots=True)
+class SubmitPayloadParseResult:
+    """提交响应解析结果。"""
+
+    payload: dict[str, Any] | None
+    error_type: str | None = None
+    error_message: str | None = None
+
+
+class AsyncSubmitOutcomeBuilderService:
+    """异步提交结果构建服务。"""
+
+    def __init__(self, *, sanitize: Callable[[str], str]) -> None:
+        self._sanitize = sanitize
+
+    def parse_payload(self, *, response: httpx.Response) -> SubmitPayloadParseResult:
+        payload: dict[str, Any] | None = None
+        try:
+            data = response.json()
+            if isinstance(data, dict):
+                payload = data
+        except Exception as exc:
+            return SubmitPayloadParseResult(
+                payload=None,
+                error_type=type(exc).__name__,
+                error_message=self._sanitize(str(exc)),
+            )
+        return SubmitPayloadParseResult(payload=payload)
+
+    @staticmethod
+    def build_success_outcome(
+        *,
+        candidate: Any,
+        candidate_keys: list[dict[str, Any]],
+        external_task_id: str,
+        rule_lookup: BillingRuleLookupResult | None,
+        payload: dict[str, Any] | None,
+        response: httpx.Response,
+    ) -> SubmitOutcome:
+        return SubmitOutcome(
+            candidate=candidate,
+            candidate_keys=candidate_keys,
+            external_task_id=external_task_id,
+            rule_lookup=rule_lookup,
+            upstream_payload=payload,
+            upstream_headers=dict(response.headers),
+            upstream_status_code=response.status_code,
+        )

src/services/task/submit/prepare.py

@@ -0,0 +1,121 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.core.logger import logger
+from src.models.database import ApiKey
+from src.services.candidate.resolver import CandidateResolver
+from src.services.candidate.submit import AllCandidatesFailedError
+from src.services.scheduling.aware_scheduler import get_cache_aware_scheduler
+from src.services.system.config import SystemConfigService
+from src.services.task.submit import ApplyPoolReorderFn, ExpandPoolCandidatesFn
+
+
+@dataclass(slots=True)
+class PreparedSubmitCandidates:
+    """异步提交前的候选准备结果。"""
+
+    candidates: list[Any]
+    record_map: dict[tuple[int, int], str]
+
+
+class AsyncSubmitPreparationService:
+    """异步提交候选准备服务。"""
+
+    def __init__(
+        self,
+        db: Session,
+        redis_client: Any | None,
+        *,
+        sanitize: Callable[[str], str],
+    ) -> None:
+        self.db = db
+        self.redis = redis_client
+        self._sanitize = sanitize
+
+    async def prepare_candidates(
+        self,
+        *,
+        api_format: str,
+        model_name: str,
+        affinity_key: str,
+        user_api_key: ApiKey,
+        request_id: str | None,
+        capability_requirements: dict[str, bool] | None,
+        request_body: dict[str, Any] | None,
+        max_candidates: int | None,
+        apply_pool_reorder: ApplyPoolReorderFn,
+        expand_pool_candidates_for_async_submit: ExpandPoolCandidatesFn,
+    ) -> PreparedSubmitCandidates:
+        priority_mode = SystemConfigService.get_config(
+            self.db,
+            "provider_priority_mode",
+            "provider",
+        )
+        scheduling_mode = SystemConfigService.get_config(
+            self.db,
+            "scheduling_mode",
+            "cache_affinity",
+        )
+        cache_scheduler = await get_cache_aware_scheduler(
+            self.redis,
+            priority_mode=priority_mode,
+            scheduling_mode=scheduling_mode,
+        )
+        resolver = CandidateResolver(db=self.db, cache_scheduler=cache_scheduler)
+
+        candidates, _global_model_id = await resolver.fetch_candidates(
+            api_format=api_format,
+            model_name=model_name,
+            affinity_key=affinity_key,
+            user_api_key=user_api_key,
+            request_id=request_id,
+            is_stream=False,
+            capability_requirements=capability_requirements,
+            request_body=request_body,
+        )
+        _ = _global_model_id
+
+        if not candidates:
+            raise AllCandidatesFailedError(
+                reason="no_candidates",
+                candidate_keys=[],
+                last_status_code=None,
+            )
+
+        # Account Pool: keep internal key failover order/skip behavior
+        # consistent with the SYNC path.
+        candidates, _pool_traces = await apply_pool_reorder(
+            candidates,
+            request_body=request_body,
+        )
+        _ = _pool_traces
+        candidates = expand_pool_candidates_for_async_submit(candidates)
+
+        if max_candidates is not None and max_candidates > 0:
+            candidates = candidates[:max_candidates]
+
+        # Pre-create RequestCandidate records (no retry expand for async submit stage)
+        record_map: dict[tuple[int, int], str] = {}
+        if request_id:
+            try:
+                record_map = resolver.create_candidate_records(
+                    all_candidates=candidates,
+                    request_id=request_id,
+                    user_id=str(user_api_key.user_id),
+                    user_api_key=user_api_key,
+                    required_capabilities=capability_requirements,
+                    expand_retries=False,
+                )
+            except Exception as exc:
+                logger.warning(
+                    "[TaskService] Failed to create candidate records: {}",
+                    self._sanitize(str(exc)),
+                )
+                record_map = {}
+
+        return PreparedSubmitCandidates(candidates=candidates, record_map=record_map)

src/services/task/submit/record.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+from sqlalchemy import update
+from sqlalchemy.orm import Session
+
+from src.models.database import RequestCandidate
+
+
+class AsyncSubmitRecordService:
+    """异步提交阶段的 RequestCandidate 落库服务。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    def mark_pending(self, *, record_id: str | None) -> None:
+        if not record_id:
+            return
+        started_at = datetime.now(timezone.utc)
+        self.db.execute(
+            update(RequestCandidate)
+            .where(RequestCandidate.id == record_id)
+            .values(status="pending", started_at=started_at)
+        )
+
+    def mark_failed(
+        self,
+        *,
+        record_id: str | None,
+        error_type: str,
+        error_message: str,
+        status_code: int | None = None,
+    ) -> None:
+        if not record_id:
+            return
+
+        values: dict[str, object] = {
+            "status": "failed",
+            "error_type": error_type,
+            "error_message": error_message,
+            "finished_at": datetime.now(timezone.utc),
+        }
+        if status_code is not None:
+            values["status_code"] = status_code
+
+        self.db.execute(
+            update(RequestCandidate).where(RequestCandidate.id == record_id).values(**values)
+        )
+
+    def mark_success(
+        self,
+        *,
+        record_id: str | None,
+        status_code: int,
+    ) -> None:
+        if not record_id:
+            return
+        self.db.execute(
+            update(RequestCandidate)
+            .where(RequestCandidate.id == record_id)
+            .values(
+                status="success",
+                status_code=status_code,
+                finished_at=datetime.now(timezone.utc),
+            )
+        )

src/services/task/submit/response.py

@@ -0,0 +1,201 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Any
+
+import httpx
+from sqlalchemy.orm import Session
+
+from src.core.logger import logger
+from src.services.billing.rule_service import BillingRuleLookupResult
+from src.services.candidate.submit import SubmitOutcome, UpstreamClientRequestError
+from src.services.task.submit.outcome_builder import (
+    AsyncSubmitOutcomeBuilderService,
+)
+from src.services.task.submit.record import AsyncSubmitRecordService
+from src.services.task.submit.rule_decider import AsyncSubmitRuleDeciderService
+
+
+class AsyncSubmitResponseService:
+    """异步提交响应判定服务。"""
+
+    def __init__(
+        self,
+        db: Session,
+        *,
+        record_ops: AsyncSubmitRecordService,
+        sanitize: Callable[[str], str],
+        extract_response_text: Callable[[httpx.Response], str],
+        match_provider_failover_rule: Callable[..., str | None],
+    ) -> None:
+        self.db = db
+        self._record_ops = record_ops
+        self._sanitize = sanitize
+        self._extract_response_text = extract_response_text
+        self._rule_decider = AsyncSubmitRuleDeciderService(
+            match_provider_failover_rule=match_provider_failover_rule
+        )
+        self._outcome_builder = AsyncSubmitOutcomeBuilderService(sanitize=sanitize)
+
+    def handle_submit_exception(
+        self,
+        *,
+        record_id: str | None,
+        candidate_info: dict[str, Any],
+        exc: Exception,
+    ) -> tuple[None, None]:
+        error_type = type(exc).__name__
+        error_msg = self._sanitize(str(exc))
+        candidate_info.update(
+            {
+                "attempt_status": "exception",
+                "error_type": error_type,
+                "error_message": error_msg,
+            }
+        )
+        self._record_ops.mark_failed(
+            record_id=record_id,
+            error_type=error_type,
+            error_message=error_msg,
+        )
+        return None, None
+
+    def handle_submit_response(
+        self,
+        *,
+        candidate: Any,
+        record_id: str | None,
+        candidate_info: dict[str, Any],
+        candidate_keys: list[dict[str, Any]],
+        rule_lookup: BillingRuleLookupResult | None,
+        response: httpx.Response,
+        extract_external_task_id: Any,
+    ) -> tuple[SubmitOutcome | None, int | None]:
+        last_status_code = int(getattr(response, "status_code", 0) or 0)
+
+        if response.status_code >= 400:
+            error_text = self._extract_response_text(response)
+            error_msg = self._sanitize(error_text)
+            candidate_info.update(
+                {
+                    "attempt_status": "http_error",
+                    "status_code": response.status_code,
+                    "error_message": error_msg,
+                }
+            )
+            self._record_ops.mark_failed(
+                record_id=record_id,
+                status_code=response.status_code,
+                error_type="http_error",
+                error_message=error_msg,
+            )
+
+            stop_pattern = self._rule_decider.detect_error_stop_pattern(
+                candidate=candidate,
+                response_text=error_text,
+                status_code=response.status_code,
+            )
+            if stop_pattern:
+                logger.info(
+                    "[TaskService] 错误终止规则命中: pattern={}, status_code={}, provider={}",
+                    stop_pattern,
+                    response.status_code,
+                    candidate.provider.name,
+                )
+                candidate_info["stop_rule_pattern"] = stop_pattern
+                try:
+                    self.db.commit()
+                except Exception:
+                    self.db.rollback()
+                raise UpstreamClientRequestError(
+                    response=response,
+                    candidate_keys=candidate_keys,
+                )
+            return None, last_status_code
+
+        success_text = self._extract_response_text(response)
+        success_continue_pattern = self._rule_decider.detect_success_failover_pattern(
+            candidate=candidate,
+            response_text=success_text,
+            status_code=response.status_code,
+        )
+        if success_continue_pattern:
+            logger.info(
+                "[TaskService] 成功转移规则命中: pattern={}, status_code={}, provider={}",
+                success_continue_pattern,
+                response.status_code,
+                candidate.provider.name,
+            )
+            failover_reason = f"success_failover_rule_matched:{success_continue_pattern}"
+            candidate_info.update(
+                {
+                    "attempt_status": "success_failover",
+                    "status_code": response.status_code,
+                    "error_message": failover_reason,
+                    "success_rule_pattern": success_continue_pattern,
+                }
+            )
+            self._record_ops.mark_failed(
+                record_id=record_id,
+                status_code=response.status_code,
+                error_type="success_failover_pattern",
+                error_message=failover_reason,
+            )
+            return None, last_status_code
+
+        parse_result = self._outcome_builder.parse_payload(response=response)
+        if parse_result.error_type:
+            candidate_info.update(
+                {
+                    "attempt_status": "invalid_json",
+                    "error_type": parse_result.error_type,
+                    "error_message": parse_result.error_message,
+                }
+            )
+            self._record_ops.mark_failed(
+                record_id=record_id,
+                status_code=response.status_code,
+                error_type="invalid_json",
+                error_message=parse_result.error_message or "invalid_json",
+            )
+            return None, last_status_code
+
+        payload = parse_result.payload
+        external_task_id = extract_external_task_id(payload or {})
+        if not external_task_id:
+            candidate_info.update(
+                {
+                    "attempt_status": "empty_task_id",
+                    "error_message": "Upstream returned empty task id",
+                }
+            )
+            self._record_ops.mark_failed(
+                record_id=record_id,
+                status_code=response.status_code,
+                error_type="empty_task_id",
+                error_message="Upstream returned empty task id",
+            )
+            return None, last_status_code
+
+        # Success
+        candidate_info.update({"attempt_status": "success", "selected": True})
+        self._record_ops.mark_success(
+            record_id=record_id,
+            status_code=response.status_code,
+        )
+        try:
+            self.db.commit()
+        except Exception:
+            self.db.rollback()
+
+        return (
+            self._outcome_builder.build_success_outcome(
+                candidate=candidate,
+                candidate_keys=candidate_keys,
+                external_task_id=str(external_task_id),
+                rule_lookup=rule_lookup,
+                payload=payload,
+                response=response,
+            ),
+            last_status_code,
+        )

src/services/task/submit/rule_decider.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+from typing import Any
+
+
+class AsyncSubmitRuleDeciderService:
+    """异步提交故障转移规则判定服务。"""
+
+    def __init__(
+        self,
+        *,
+        match_provider_failover_rule: Callable[..., str | None],
+    ) -> None:
+        self._match_provider_failover_rule = match_provider_failover_rule
+
+    def detect_error_stop_pattern(
+        self,
+        *,
+        candidate: Any,
+        response_text: str,
+        status_code: int,
+    ) -> str | None:
+        return self._match_provider_failover_rule(
+            candidate,
+            is_success=False,
+            response_text=response_text,
+            status_code=status_code,
+        )
+
+    def detect_success_failover_pattern(
+        self,
+        *,
+        candidate: Any,
+        response_text: str,
+        status_code: int,
+    ) -> str | None:
+        return self._match_provider_failover_rule(
+            candidate,
+            is_success=True,
+            response_text=response_text,
+            status_code=status_code,
+        )

src/services/task/submit/submit_service.py

@@ -0,0 +1,152 @@
+from __future__ import annotations
+
+import re
+from typing import Any
+
+import httpx
+from sqlalchemy.orm import Session
+
+from src.models.database import ApiKey
+from src.services.candidate.failover import FailoverEngine
+from src.services.candidate.submit import SubmitOutcome
+from src.services.task.submit import ApplyPoolReorderFn, ExpandPoolCandidatesFn
+from src.services.task.submit.execute import AsyncSubmitExecutionService
+from src.services.task.submit.prepare import AsyncSubmitPreparationService
+
+_SENSITIVE_PATTERN = re.compile(
+    r"(api[_-]?key|token|bearer|authorization)[=:\s]+\S+",
+    re.IGNORECASE,
+)
+
+
+class AsyncTaskSubmitService:
+    """异步任务提交应用服务（候选选择 + 故障转移）。"""
+
+    def __init__(
+        self,
+        db: Session,
+        redis_client: Any | None,
+        *,
+        apply_pool_reorder: ApplyPoolReorderFn,
+        expand_pool_candidates_for_async_submit: ExpandPoolCandidatesFn,
+    ) -> None:
+        self.db = db
+        self.redis = redis_client
+        self._apply_pool_reorder = apply_pool_reorder
+        self._expand_pool_candidates_for_async_submit = expand_pool_candidates_for_async_submit
+        self._prepare_ops = AsyncSubmitPreparationService(
+            db,
+            redis_client,
+            sanitize=self._sanitize,
+        )
+        self._execute_ops = AsyncSubmitExecutionService(
+            db,
+            sanitize=self._sanitize,
+            extract_response_text=self._extract_response_text,
+            match_provider_failover_rule=self._match_provider_failover_rule,
+        )
+
+    @staticmethod
+    def _sanitize(message: str, max_length: int = 200) -> str:
+        if not message:
+            return "request_failed"
+        return _SENSITIVE_PATTERN.sub("[REDACTED]", message)[:max_length]
+
+    @staticmethod
+    def _extract_response_text(response: httpx.Response) -> str:
+        try:
+            return response.text or ""
+        except Exception:
+            return ""
+
+    @staticmethod
+    def _match_provider_failover_rule(
+        candidate: Any,
+        *,
+        is_success: bool,
+        response_text: str,
+        status_code: int | None = None,
+    ) -> str | None:
+        provider_config = getattr(candidate.provider, "config", None) or {}
+        rules = provider_config.get("failover_rules")
+        if not rules or not isinstance(rules, dict):
+            return None
+
+        compiled = FailoverEngine._get_compiled_patterns(rules)
+        key = "success" if is_success else "error"
+
+        for regex, rule in compiled.get(key, []):
+            if not is_success:
+                rule_status_codes = rule.get("status_codes")
+                if rule_status_codes and status_code not in rule_status_codes:
+                    continue
+            if regex.search(response_text):
+                return rule.get("pattern", "")
+
+        return None
+
+    async def submit_with_failover(
+        self,
+        *,
+        api_format: str,
+        model_name: str,
+        affinity_key: str,
+        user_api_key: ApiKey,
+        request_id: str | None,
+        task_type: str,
+        submit_func: Any,
+        extract_external_task_id: Any,
+        supported_auth_types: set[str] | None = None,
+        allow_format_conversion: bool = False,
+        capability_requirements: dict[str, bool] | None = None,
+        max_candidates: int | None = None,
+        request_body: dict[str, Any] | None = None,
+    ) -> SubmitOutcome:
+        """
+        异步提交入口。
+
+        行为保持与原 TaskService.submit_with_failover 一致：
+        - 按候选顺序依次尝试（提交阶段不做单候选重试）
+        - 记录 RequestCandidate 审计行
+        - 命中 error_stop_patterns 时立即停止并抛出上游错误
+        - 命中 success_failover_patterns 时继续尝试下一个候选
+        """
+        # IMPORTANT:
+        # This method awaits upstream HTTP calls. If we have an open DB transaction before awaiting,
+        # the connection can be held for a long time (pool exhaustion under concurrency).
+        #
+        # Also note SQLAlchemy's default expire_on_commit=True would expire ORM objects and may
+        # trigger unexpected lazy DB loads after we commit (potentially during the await).
+        # We disable it temporarily to keep candidate/provider/key objects in-memory.
+        original_expire_on_commit = getattr(self.db, "expire_on_commit", True)
+        self.db.expire_on_commit = False
+
+        try:
+            prepared = await self._prepare_ops.prepare_candidates(
+                api_format=api_format,
+                model_name=model_name,
+                affinity_key=affinity_key,
+                user_api_key=user_api_key,
+                request_id=request_id,
+                capability_requirements=capability_requirements,
+                request_body=request_body,
+                max_candidates=max_candidates,
+                apply_pool_reorder=self._apply_pool_reorder,
+                expand_pool_candidates_for_async_submit=(
+                    self._expand_pool_candidates_for_async_submit
+                ),
+            )
+
+            return await self._execute_ops.execute_submit_loop(
+                candidates=prepared.candidates,
+                record_map=prepared.record_map,
+                task_type=task_type,
+                model_name=model_name,
+                submit_func=submit_func,
+                extract_external_task_id=extract_external_task_id,
+                supported_auth_types=supported_auth_types,
+                allow_format_conversion=allow_format_conversion,
+            )
+        finally:
+            # Restore Session behavior for the rest of the request lifecycle.
+            self.db.expire_on_commit = original_expire_on_commit

src/services/task/video/billing.py

@@ -0,0 +1,320 @@
+from __future__ import annotations
+
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.core.api_format.conversion.internal_video import VideoStatus
+from src.core.logger import logger
+from src.models.database import ApiKey, Provider, Usage, User
+from src.services.usage.service import UsageService
+
+
+class VideoTaskBillingService:
+    """视频任务计费/结算服务。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    async def _create_fallback_usage_for_video_task(self, task: Any, request_id: str) -> bool:
+        """
+        Fallback: create a Usage row if it's missing (should be rare).
+
+        This keeps behavior compatible with the old Phase2 finalize logic.
+        """
+        user_obj = self.db.query(User).filter(User.id == task.user_id).first()
+        api_key_obj = (
+            self.db.query(ApiKey).filter(ApiKey.id == task.api_key_id).first()
+            if getattr(task, "api_key_id", None)
+            else None
+        )
+        provider_obj = (
+            self.db.query(Provider).filter(Provider.id == task.provider_id).first()
+            if getattr(task, "provider_id", None)
+            else None
+        )
+        provider_name = provider_obj.name if provider_obj else "unknown"
+
+        response_time_ms: int | None = None
+        if getattr(task, "submitted_at", None) and getattr(task, "completed_at", None):
+            delta = task.completed_at - task.submitted_at
+            response_time_ms = int(delta.total_seconds() * 1000)
+
+        request_headers: dict[str, Any] | None = None
+        if isinstance(getattr(task, "request_metadata", None), dict):
+            task_meta = task.request_metadata
+            for header_key in ("request_headers", "headers", "original_headers"):
+                raw_headers = task_meta.get(header_key)
+                if isinstance(raw_headers, dict):
+                    request_headers = dict(raw_headers)
+                    break
+
+        try:
+            await UsageService.record_usage_with_custom_cost(
+                db=self.db,
+                user=user_obj,
+                api_key=api_key_obj,
+                provider=provider_name,
+                model=task.model,
+                request_type="video",
+                total_cost_usd=0.0,
+                request_cost_usd=0.0,
+                input_tokens=0,
+                output_tokens=0,
+                cache_creation_input_tokens=0,
+                cache_read_input_tokens=0,
+                api_format=task.client_api_format,
+                endpoint_api_format=task.provider_api_format,
+                has_format_conversion=bool(getattr(task, "format_converted", False)),
+                is_stream=False,
+                response_time_ms=response_time_ms,
+                first_byte_time_ms=None,
+                status_code=200 if task.status == "completed" else 500,
+                error_message=(
+                    None
+                    if task.status == "completed"
+                    else (task.error_message or task.error_code or "video_task_failed")
+                ),
+                metadata={
+                    "fallback_created": True,
+                    "video_task_id": task.id,
+                },
+                request_headers=request_headers,
+                request_body=getattr(task, "original_request_body", None),
+                provider_request_headers=None,
+                response_headers=None,
+                client_response_headers=None,
+                response_body=None,
+                request_id=request_id,
+                provider_id=getattr(task, "provider_id", None),
+                provider_endpoint_id=getattr(task, "endpoint_id", None),
+                provider_api_key_id=getattr(task, "key_id", None),
+                status="completed" if task.status == "completed" else "failed",
+                target_model=None,
+            )
+            return True
+        except Exception as exc:
+            logger.exception(
+                "Failed to create fallback usage for video task={}: {}",
+                task.id,
+                str(exc),
+            )
+            return False
+
+    async def finalize_video_task(self, task: Any) -> bool:
+        """
+        Update billing/usage for a completed/failed video task.
+
+        Async video billing flow:
+        - Submit success: Usage is already settled with cost=0
+        - Poll completion: update actual cost (success -> bill, failure -> keep 0)
+
+        Returns True when updated, False when skipped (already finalized).
+        """
+        from datetime import datetime, timezone
+
+        from src.services.billing.dimension_collector_service import DimensionCollectorService
+        from src.services.billing.formula_engine import BillingIncompleteError, FormulaEngine
+        from src.services.billing.rule_service import BillingRuleService
+
+        request_id = getattr(task, "request_id", None) or getattr(task, "id", None)
+        if not request_id:
+            return False
+
+        existing = self.db.query(Usage).filter(Usage.request_id == request_id).first()
+        if not existing:
+            logger.warning(
+                "Usage not found for video task, creating fallback: task_id={} request_id={}",
+                getattr(task, "id", None),
+                request_id,
+            )
+            return await self._create_fallback_usage_for_video_task(task, request_id)
+
+        metadata = existing.request_metadata or {}
+        if metadata.get("billing_updated_at"):
+            logger.debug(
+                "Video task billing already updated: task_id={} request_id={}",
+                getattr(task, "id", None),
+                request_id,
+            )
+            return False
+
+        response_time_ms: int | None = None
+        if getattr(task, "submitted_at", None) and getattr(task, "completed_at", None):
+            delta = task.completed_at - task.submitted_at
+            response_time_ms = int(delta.total_seconds() * 1000)
+
+        base_dimensions: dict[str, Any] = {
+            "duration_seconds": getattr(task, "duration_seconds", None),
+            "resolution": getattr(task, "resolution", None),
+            "aspect_ratio": getattr(task, "aspect_ratio", None),
+            "size": getattr(task, "size", None) or "",
+            "retry_count": getattr(task, "retry_count", 0),
+        }
+
+        collector_metadata: dict[str, Any] = {
+            "task": {
+                "id": getattr(task, "id", None),
+                "external_task_id": getattr(task, "external_task_id", None),
+                "model": getattr(task, "model", None),
+                "duration_seconds": getattr(task, "duration_seconds", None),
+                "resolution": getattr(task, "resolution", None),
+                "aspect_ratio": getattr(task, "aspect_ratio", None),
+                "size": getattr(task, "size", None),
+                "retry_count": getattr(task, "retry_count", 0),
+                "video_size_bytes": getattr(task, "video_size_bytes", None),
+            },
+            "result": {
+                "video_url": getattr(task, "video_url", None),
+                "video_urls": getattr(task, "video_urls", None) or [],
+            },
+        }
+
+        poll_raw = None
+        if isinstance(getattr(task, "request_metadata", None), dict):
+            poll_raw = task.request_metadata.get("poll_raw_response")
+
+        dims = DimensionCollectorService(self.db).collect_dimensions(
+            api_format=getattr(task, "provider_api_format", None),
+            task_type="video",
+            request=getattr(task, "original_request_body", None) or {},
+            response=poll_raw if isinstance(poll_raw, dict) else None,
+            metadata=collector_metadata,
+            base_dimensions=base_dimensions,
+        )
+
+        # Prefer frozen rule snapshot from submit stage.
+        rule_snapshot = None
+        if isinstance(getattr(task, "request_metadata", None), dict):
+            rule_snapshot = task.request_metadata.get("billing_rule_snapshot")
+
+        expression = None
+        variables: dict[str, Any] | None = None
+        dimension_mappings: dict[str, dict[str, Any]] | None = None
+        rule_id = None
+        rule_name = None
+        rule_scope = None
+
+        if isinstance(rule_snapshot, dict) and rule_snapshot.get("status") == "ok":
+            rule_id = rule_snapshot.get("rule_id")
+            rule_name = rule_snapshot.get("rule_name")
+            rule_scope = rule_snapshot.get("scope")
+            expression = rule_snapshot.get("expression")
+            variables = rule_snapshot.get("variables") or {}
+            dimension_mappings = rule_snapshot.get("dimension_mappings") or {}
+        else:
+            lookup = BillingRuleService.find_rule(
+                self.db,
+                provider_id=getattr(task, "provider_id", None),
+                model_name=getattr(task, "model", None),
+                task_type="video",
+            )
+            if lookup:
+                rule = lookup.rule
+                rule_id = getattr(rule, "id", None)
+                rule_name = getattr(rule, "name", None)
+                rule_scope = getattr(lookup, "scope", None)
+                expression = getattr(rule, "expression", None)
+                variables = getattr(rule, "variables", None) or {}
+                dimension_mappings = getattr(rule, "dimension_mappings", None) or {}
+
+        billing_snapshot: dict[str, Any] = {
+            "schema_version": "1.0",
+            "rule_id": str(rule_id) if rule_id else None,
+            "rule_name": str(rule_name) if rule_name else None,
+            "scope": str(rule_scope) if rule_scope else None,
+            "expression": str(expression) if expression else None,
+            "dimensions_used": dims,
+            "missing_required": [],
+            "cost": 0.0,
+            "status": "no_rule",
+            "calculated_at": datetime.now(timezone.utc).isoformat(),
+        }
+
+        cost = 0.0
+        is_success = str(getattr(task, "status", "")) in {
+            VideoStatus.COMPLETED.value,
+            "completed",
+        }
+
+        if is_success and expression:
+            engine = FormulaEngine()
+            try:
+                result = engine.evaluate(
+                    expression=str(expression),
+                    variables=variables,
+                    dimensions=dims,
+                    dimension_mappings=dimension_mappings,
+                    strict_mode=config.billing_strict_mode,
+                )
+                billing_snapshot["status"] = result.status
+                billing_snapshot["missing_required"] = result.missing_required
+                if result.status == "complete":
+                    cost = float(result.cost)
+                billing_snapshot["cost"] = cost
+            except BillingIncompleteError as exc:
+                # strict_mode=true: mark task failed and hide artifacts (avoid free pass)
+                task.status = VideoStatus.FAILED.value
+                task.error_code = "billing_incomplete"
+                task.error_message = f"Missing required dimensions: {exc.missing_required}"
+                task.video_url = None
+                task.video_urls = None
+                billing_snapshot["status"] = "incomplete"
+                billing_snapshot["missing_required"] = exc.missing_required
+                billing_snapshot["cost"] = 0.0
+                cost = 0.0
+            except Exception as exc:
+                billing_snapshot["status"] = "incomplete"
+                billing_snapshot["error"] = str(exc)
+                billing_snapshot["cost"] = 0.0
+                cost = 0.0
+
+        # Write back to task.request_metadata for audit/recalc.
+        task_meta = dict(task.request_metadata) if getattr(task, "request_metadata", None) else {}
+        task_meta["billing_snapshot"] = billing_snapshot
+        task.request_metadata = task_meta
+
+        updated = UsageService.update_settled_billing(
+            self.db,
+            request_id=request_id,
+            total_cost_usd=cost,
+            request_cost_usd=cost,
+            status="completed" if str(getattr(task, "status", "")) == "completed" else "failed",
+            status_code=200 if str(getattr(task, "status", "")) == "completed" else 500,
+            error_message=(
+                None
+                if str(getattr(task, "status", "")) == "completed"
+                else (
+                    getattr(task, "error_message", None)
+                    or getattr(task, "error_code", None)
+                    or "video_task_failed"
+                )
+            ),
+            response_time_ms=response_time_ms,
+            billing_snapshot=billing_snapshot,
+            extra_metadata={
+                "dimensions": dims,
+                "raw_response_ref": {
+                    "video_task_id": getattr(task, "id", None),
+                    "field": "video_tasks.request_metadata.poll_raw_response",
+                },
+            },
+        )
+
+        if updated:
+            logger.debug(
+                "Updated video task billing: task_id={} request_id={} cost={:.6f}",
+                getattr(task, "id", None),
+                request_id,
+                cost,
+            )
+        else:
+            logger.warning(
+                "Failed to update video task billing (may already be updated): "
+                "task_id={} request_id={}",
+                getattr(task, "id", None),
+                request_id,
+            )
+
+        return bool(updated)

src/services/task/video/cancel.py

@@ -0,0 +1,149 @@
+from __future__ import annotations
+
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.core.logger import logger
+from src.models.database import ProviderAPIKey, ProviderEndpoint
+from src.services.usage.service import UsageService
+
+
+class VideoTaskCancelService:
+    """视频任务取消服务（上游取消 + 本地状态与计费回写）。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    async def cancel_task(
+        self,
+        *,
+        task: Any,
+        task_id: str,
+        original_headers: dict[str, str] | None = None,
+    ) -> Any:
+        """
+        Cancel a video task (best-effort) and void its Usage (no charge).
+
+        Returns:
+        - None on success
+        - upstream httpx.Response when upstream returns an error (status >= 400)
+        """
+        from datetime import datetime, timezone
+
+        from fastapi import HTTPException
+
+        from src.clients.http_client import HTTPClientPool
+        from src.core.api_format import (
+            build_upstream_headers_for_endpoint,
+            get_extra_headers_from_endpoint,
+            make_signature_key,
+        )
+        from src.core.api_format.conversion.internal_video import VideoStatus
+        from src.core.crypto import crypto_service
+        from src.services.provider.auth import get_provider_auth
+        from src.services.provider.transport import build_provider_url
+
+        external_task_id = getattr(task, "external_task_id", None)
+        if not external_task_id:
+            raise HTTPException(status_code=500, detail="Task missing external_task_id")
+
+        endpoint = (
+            self.db.query(ProviderEndpoint).filter(ProviderEndpoint.id == task.endpoint_id).first()
+        )
+        key = self.db.query(ProviderAPIKey).filter(ProviderAPIKey.id == task.key_id).first()
+        if not endpoint or not key:
+            raise HTTPException(status_code=500, detail="Provider endpoint or key not found")
+        if not getattr(key, "api_key", None):
+            raise HTTPException(status_code=500, detail="Provider key not configured")
+
+        upstream_key = crypto_service.decrypt(key.api_key)
+        extra_headers = get_extra_headers_from_endpoint(endpoint)
+
+        raw_family = str(getattr(endpoint, "api_family", "") or "").strip().lower()
+        raw_kind = str(getattr(endpoint, "endpoint_kind", "") or "").strip().lower()
+        provider_format = (
+            make_signature_key(raw_family, raw_kind)
+            if raw_family and raw_kind
+            else str(
+                getattr(endpoint, "api_format", "")
+                or getattr(task, "provider_api_format", "")
+                or ""
+            )
+        )
+        provider_format_norm = provider_format.strip().lower()
+
+        headers = build_upstream_headers_for_endpoint(
+            original_headers or {},
+            provider_format,
+            upstream_key,
+            endpoint_headers=extra_headers,
+            header_rules=getattr(endpoint, "header_rules", None),
+        )
+
+        client = await HTTPClientPool.get_default_client_async()
+
+        if provider_format_norm.startswith("openai:"):
+            upstream_url = build_provider_url(endpoint, is_stream=False, key=key)
+            upstream_url = f"{upstream_url.rstrip('/')}/{str(external_task_id).lstrip('/')}"
+            response = await client.delete(upstream_url, headers=headers)
+            if response.status_code >= 400:
+                return response
+
+        elif provider_format_norm.startswith("gemini:"):
+            # Gemini cancel endpoint supports both:
+            # - operations/{id}:cancel
+            # - models/{model}/operations/{id}:cancel
+            operation_name = str(external_task_id)
+            if not (
+                operation_name.startswith("operations/") or operation_name.startswith("models/")
+            ):
+                operation_name = f"operations/{operation_name}"
+
+            base = (
+                getattr(endpoint, "base_url", None) or "https://generativelanguage.googleapis.com"
+            ).rstrip("/")
+            if base.endswith("/v1beta"):
+                base = base[: -len("/v1beta")]
+            upstream_url = f"{base}/v1beta/{operation_name}:cancel"
+
+            auth_info = await get_provider_auth(endpoint, key)
+            if auth_info:
+                headers.pop("x-goog-api-key", None)
+                headers[auth_info.auth_header] = auth_info.auth_value
+
+            response = await client.post(upstream_url, headers=headers, json={})
+            if response.status_code >= 400:
+                return response
+
+        else:
+            raise HTTPException(
+                status_code=400,
+                detail=f"Cancel not supported for provider format: {provider_format}",
+            )
+
+        task.status = VideoStatus.CANCELLED.value
+        task.updated_at = datetime.now(timezone.utc)
+
+        # Void Usage (no charge)
+        try:
+            voided = UsageService.finalize_void(
+                self.db,
+                request_id=task.request_id,
+                reason="cancelled_by_user",
+            )
+            if not voided:
+                UsageService.void_settled(
+                    self.db,
+                    request_id=task.request_id,
+                    reason="cancelled_by_user",
+                )
+        except Exception as exc:
+            logger.warning(
+                "Failed to void usage for cancelled task={}: {}",
+                getattr(task, "id", task_id),
+                str(exc),
+            )
+
+        self.db.commit()
+        return None

src/services/task/video/facade.py

@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+from typing import Any
+
+from src.services.task.core.schema import TaskStatusResult
+from src.services.task.video.operations import VideoTaskOperationsService
+
+
+class TaskVideoFacadeService:
+    """视频任务门面服务（向后兼容 TaskService 的视频公开方法）。"""
+
+    def __init__(self, video_ops: VideoTaskOperationsService) -> None:
+        self._video_ops = video_ops
+
+    async def poll(self, task_id: str, *, user_id: str) -> TaskStatusResult:
+        return await self._video_ops.poll(task_id, user_id=user_id)
+
+    async def poll_now(self, task_id: str, *, user_id: str) -> TaskStatusResult:
+        return await self._video_ops.poll_now(task_id, user_id=user_id)
+
+    async def cancel(
+        self,
+        task_id: str,
+        *,
+        user_id: str,
+        original_headers: dict[str, str] | None = None,
+    ) -> Any:
+        return await self._video_ops.cancel(
+            task_id,
+            user_id=user_id,
+            original_headers=original_headers,
+        )
+
+    async def finalize_video_task(self, task: Any) -> bool:
+        return await self._video_ops.finalize_video_task(task)
+
+    async def finalize(self, task_id: str) -> bool:
+        return await self._video_ops.finalize(task_id)

src/services/task/video/operations.py

@@ -0,0 +1,134 @@
+from __future__ import annotations
+
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.models.database import VideoTask
+from src.services.task.core.exceptions import TaskNotFoundError
+from src.services.task.core.schema import TaskStatusResult
+from src.services.task.video.billing import VideoTaskBillingService
+from src.services.task.video.cancel import VideoTaskCancelService
+
+
+class VideoTaskOperationsService:
+    """视频任务相关应用服务（轮询/取消/终态结算）。"""
+
+    def __init__(self, db: Session, redis_client: Any | None = None) -> None:
+        self.db = db
+        self.redis = redis_client
+        self._billing_ops = VideoTaskBillingService(db)
+        self._cancel_ops = VideoTaskCancelService(db)
+
+    def _extract_short_id(self, task_id: str) -> str:
+        # Keep the parsing rule consistent with handlers:
+        # - models/{model}/operations/{short_id}
+        # - operations/{short_id}
+        # - {short_id}
+        return task_id.rsplit("/", 1)[-1] if "/" in task_id else task_id
+
+    def _get_video_task_for_user(self, task_id: str, *, user_id: str) -> Any:
+        """
+        Resolve a video task by:
+        - internal UUID (VideoTask.id)
+        - external operation id (VideoTask.short_id)
+        """
+        task = (
+            self.db.query(VideoTask)
+            .filter(VideoTask.id == task_id, VideoTask.user_id == user_id)
+            .first()
+        )
+        if task:
+            return task
+
+        short_id = self._extract_short_id(task_id)
+        task = (
+            self.db.query(VideoTask)
+            .filter(VideoTask.short_id == short_id, VideoTask.user_id == user_id)
+            .first()
+        )
+        if not task:
+            raise TaskNotFoundError(task_id)
+        return task
+
+    async def poll(self, task_id: str, *, user_id: str) -> TaskStatusResult:
+        """Read task status from DB (does not trigger polling)."""
+        task = self._get_video_task_for_user(task_id, user_id=user_id)
+
+        result_url = None
+        if getattr(task, "status", None) == "completed":
+            result_url = getattr(task, "video_url", None)
+
+        error_message = None
+        if getattr(task, "status", None) == "failed":
+            error_message = getattr(task, "error_message", None) or getattr(
+                task, "error_code", None
+            )
+
+        return TaskStatusResult(
+            task_id=str(getattr(task, "id", task_id)),
+            status=str(getattr(task, "status", "unknown")),
+            progress_percent=int(getattr(task, "progress_percent", 0) or 0),
+            result_url=result_url,
+            error_message=str(error_message) if error_message else None,
+            provider_id=(
+                str(getattr(task, "provider_id", None))
+                if getattr(task, "provider_id", None)
+                else None
+            ),
+            provider_name=(
+                str(getattr(task, "provider_name", None))
+                if getattr(task, "provider_name", None)
+                else None
+            ),
+            endpoint_id=(
+                str(getattr(task, "endpoint_id", None))
+                if getattr(task, "endpoint_id", None)
+                else None
+            ),
+            key_id=str(getattr(task, "key_id", None)) if getattr(task, "key_id", None) else None,
+        )
+
+    async def poll_now(self, task_id: str, *, user_id: str) -> TaskStatusResult:
+        """
+        Trigger a single polling attempt (best-effort), then return latest DB status.
+
+        Note: this uses the poller adapter's single-task method and may hold a DB
+        connection during the upstream HTTP request; keep usage low.
+        """
+        from src.services.task.video.poller_adapter import VideoTaskPollerAdapter
+
+        task = self._get_video_task_for_user(task_id, user_id=user_id)
+        adapter = VideoTaskPollerAdapter()
+        await adapter.poll_single_task(self.db, task, redis_client=self.redis)
+        self.db.commit()
+        return await self.poll(task_id, user_id=user_id)
+
+    async def cancel(
+        self,
+        task_id: str,
+        *,
+        user_id: str,
+        original_headers: dict[str, str] | None = None,
+    ) -> Any:
+        from fastapi import HTTPException
+
+        try:
+            task = self._get_video_task_for_user(task_id, user_id=user_id)
+        except TaskNotFoundError:
+            raise HTTPException(status_code=404, detail="Video task not found")
+        return await self._cancel_ops.cancel_task(
+            task=task,
+            task_id=task_id,
+            original_headers=original_headers,
+        )
+
+    async def finalize_video_task(self, task: Any) -> bool:
+        return await self._billing_ops.finalize_video_task(task)
+
+    async def finalize(self, task_id: str) -> bool:
+        """Finalize a task by internal id (best-effort)."""
+        task = self.db.query(VideoTask).filter(VideoTask.id == task_id).first()
+        if not task:
+            return False
+        return await self.finalize_video_task(task)

src/services/task/video/poller_adapter.py

@@ -10,6 +10,7 @@ Implements the video-specific poll/normalize/update logic used by TaskPollerServ
 from __future__ import annotations
 
 import json
+from collections.abc import Awaitable, Callable
 from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
 from typing import Any
@@ -36,7 +37,6 @@ from src.core.video_utils import (
 from src.database import create_session
 from src.models.database import ProviderAPIKey, ProviderEndpoint, VideoTask
 from src.services.provider.auth import get_provider_auth
-from src.services.task.service import TaskService
 
 
 @dataclass(slots=True)
@@ -84,6 +84,20 @@ class PollHTTPError(RuntimeError):
         self.original_message = message
 
 
+VideoTaskFinalizeFn = Callable[[Session, VideoTask, Any | None], Awaitable[None]]
+
+
+async def _default_finalize_video_task(
+    db: Session,
+    task: VideoTask,
+    redis_client: Any | None,
+) -> None:
+    """默认终态结算逻辑（延迟导入，避免 task 模块循环依赖）。"""
+    from src.services.task.video.operations import VideoTaskOperationsService
+
+    await VideoTaskOperationsService(db, redis_client=redis_client).finalize_video_task(task)
+
+
 class VideoTaskPollerAdapter:
     task_type = "video"
 
@@ -102,9 +116,10 @@ class VideoTaskPollerAdapter:
     consecutive_failure_alert_threshold = 5
     max_backoff_seconds = 300
 
-    def __init__(self) -> None:
+    def __init__(self, finalize_video_task_fn: VideoTaskFinalizeFn | None = None) -> None:
         self._openai_normalizer = OpenAINormalizer()
         self._gemini_normalizer = GeminiNormalizer()
+        self._finalize_video_task = finalize_video_task_fn or _default_finalize_video_task
 
     def sanitize_error_message(self, message: str) -> str:
         return sanitize_error_message(message)
@@ -287,7 +302,7 @@ class VideoTaskPollerAdapter:
             # 终态结算
             if task.status in (VideoStatus.COMPLETED.value, VideoStatus.FAILED.value):
                 try:
-                    await TaskService(db, redis_client=redis_client).finalize_video_task(task)
+                    await self._finalize_video_task(db, task, redis_client)
                 except Exception as exc:
                     logger.exception(
                         "Failed to record video usage for task={}: {}",
@@ -365,77 +380,36 @@ class VideoTaskPollerAdapter:
         self, db: Session, task: VideoTask, *, redis_client: Any | None
     ) -> None:
         """
-        旧版单任务轮询方法（保留向后兼容）
+        兼容入口：复用三阶段轮询流程，避免维护重复逻辑。
-
-        注意：此方法在 HTTP 请求期间持有数据库连接，建议使用分阶段方法。
         """
-        try:
+        ctx_or_result = await self.prepare_poll_context(db, task)
-            result = await self._poll_task_status(db, task)
+
-            if result.status == VideoStatus.COMPLETED:
+        if isinstance(ctx_or_result, InternalVideoPollResult):
-                task.status = VideoStatus.COMPLETED.value
+            await self.update_task_after_poll(
-                task.video_url = result.video_url
+                task_id=task.id,
-                task.video_expires_at = result.expires_at
+                result=ctx_or_result,
-                task.completed_at = datetime.now(timezone.utc)
+                ctx=None,
-                task.progress_percent = 100
+                redis_client=redis_client,
-                if result.video_urls:
-                    task.video_urls = result.video_urls
-                if result.video_duration_seconds is not None:
-                    task.video_duration_seconds = result.video_duration_seconds
-                self._attach_poll_raw_response(task, result)
-            elif result.status == VideoStatus.FAILED:
-                task.status = VideoStatus.FAILED.value
-                task.error_code = result.error_code
-                task.error_message = result.error_message
-                task.completed_at = datetime.now(timezone.utc)
-                self._attach_poll_raw_response(task, result)
-            else:
-                task.poll_count += 1
-                task.progress_percent = result.progress_percent
-                task.next_poll_at = datetime.now(timezone.utc) + timedelta(
-                    seconds=task.poll_interval_seconds
             )
-        except Exception as exc:
+            return
-            task.poll_count += 1
-            error_msg = sanitize_error_message(str(exc))
-            logger.warning("Poll error for task {}: {}", task.id, error_msg)
-            task.progress_message = f"Poll error: {error_msg}"
 
-            status_code = exc.status_code if isinstance(exc, PollHTTPError) else None
+        ctx = ctx_or_result
-            is_permanent = self._is_permanent_error(exc, status_code=status_code)
+        error_exception: Exception | None = None
-            if is_permanent:
-                task.status = VideoStatus.FAILED.value
-                task.error_code = "poll_permanent_error"
-                task.error_message = error_msg
-                task.completed_at = datetime.now(timezone.utc)
-            else:
-                backoff = min(
-                    task.poll_interval_seconds * (2 ** min(task.retry_count, 5)),
-                    self.max_backoff_seconds,
-                )
-                task.retry_count += 1
-                task.next_poll_at = datetime.now(timezone.utc) + timedelta(seconds=backoff)
-
-        # 超时：超过最大轮询次数且未进入终态
-        task.updated_at = datetime.now(timezone.utc)
-        if task.poll_count >= task.max_poll_count and task.status not in [
-            VideoStatus.COMPLETED.value,
-            VideoStatus.FAILED.value,
-            VideoStatus.CANCELLED.value,
-        ]:
-            task.status = VideoStatus.FAILED.value
-            task.error_code = "poll_timeout"
-            task.error_message = f"Task timed out after {task.poll_count} polls"
-            task.completed_at = datetime.now(timezone.utc)
-
-        # 终态结算
-        if task.status in (VideoStatus.COMPLETED.value, VideoStatus.FAILED.value):
         try:
-                await TaskService(db, redis_client=redis_client).finalize_video_task(task)
+            result = await self.poll_task_http(ctx)
-            except Exception as exc:
+        except Exception as http_exc:
-                logger.exception(
+            error_exception = http_exc
-                    "Failed to record video usage for task={}: {}",
+            result = InternalVideoPollResult(
-                    task.id,
+                status=None,  # type: ignore[arg-type]
-                    sanitize_error_message(str(exc)),
+                error_message=str(http_exc),
+            )
+
+        await self.update_task_after_poll(
+            task_id=task.id,
+            result=result,
+            ctx=ctx,
+            redis_client=redis_client,
+            error_exception=error_exception,
         )
 
     def _attach_poll_raw_response(self, task: VideoTask, result: InternalVideoPollResult) -> None:

tests/services/test_candidate_service_submit.py

@@ -6,8 +6,13 @@ import httpx
 import pytest
 
 from src.config.settings import config
-from src.services.candidate.submit import AllCandidatesFailedError, UpstreamClientRequestError
+from src.services.candidate.submit import (
+    AllCandidatesFailedError,
+    SubmitOutcome,
+    UpstreamClientRequestError,
+)
 from src.services.task.service import TaskService
+from src.services.task.submit.outcome_builder import SubmitPayloadParseResult
 
 
 def _make_candidate(
@@ -356,7 +361,7 @@ async def test_submit_with_failover_applies_pool_reorder_before_submit(
 
     reordered = [pool_candidate_b, pool_candidate_a]
     apply_pool_reorder = AsyncMock(return_value=(reordered, []))
-    monkeypatch.setattr(svc, "_apply_pool_reorder", apply_pool_reorder)
+    monkeypatch.setattr(svc._submit_ops, "_apply_pool_reorder", apply_pool_reorder)  # type: ignore[attr-defined]
 
     submit = AsyncMock(return_value=httpx.Response(200, json={"id": "task-pooled"}))
     body = {"session_id": "sid-123"}
@@ -379,8 +384,245 @@ async def test_submit_with_failover_applies_pool_reorder_before_submit(
     assert outcome.candidate.key.id == "k-b"
     assert submit.await_count == 1
     fetch_candidates.assert_awaited_once()
-    assert fetch_candidates.await_args.kwargs.get("request_body") == body
+    await_args = fetch_candidates.await_args
+    assert await_args is not None
+    assert await_args.kwargs.get("request_body") == body
     apply_pool_reorder.assert_awaited_once_with(
         [pool_candidate_a, pool_candidate_b],
         request_body=body,
     )
+
+
+@pytest.mark.asyncio
+async def test_submit_with_failover_orchestrates_prepare_and_execute_layers() -> None:
+    db = MagicMock()
+    svc = TaskService(db)
+    candidate = _make_candidate(provider_id="p2", endpoint_id="e2", key_id="k2")
+
+    prepared = SimpleNamespace(candidates=[candidate], record_map={(0, 0): "rc-1"})
+    outcome = SubmitOutcome(
+        candidate=candidate,  # type: ignore[arg-type]
+        candidate_keys=[{"index": 0, "provider_id": "p2", "selected": True}],
+        external_task_id="task-layered",
+        rule_lookup=None,
+        upstream_payload={"id": "task-layered"},
+        upstream_headers={"x-test": "1"},
+        upstream_status_code=200,
+    )
+
+    svc._submit_ops._prepare_ops.prepare_candidates = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=prepared
+    )
+    svc._submit_ops._execute_ops.execute_submit_loop = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=outcome
+    )
+
+    result = await svc.submit_with_failover(
+        api_format="openai:video",
+        model_name="sora",
+        affinity_key="a1",
+        user_api_key=MagicMock(user_id="u1"),
+        request_id="rid-1",
+        task_type="video",
+        submit_func=AsyncMock(),
+        extract_external_task_id=lambda payload: payload.get("id"),
+        supported_auth_types={"api_key"},
+        allow_format_conversion=False,
+        max_candidates=10,
+    )
+
+    assert result.external_task_id == "task-layered"
+    svc._submit_ops._prepare_ops.prepare_candidates.assert_awaited_once()  # type: ignore[attr-defined]
+    svc._submit_ops._execute_ops.execute_submit_loop.assert_awaited_once()  # type: ignore[attr-defined]
+
+
+@pytest.mark.asyncio
+async def test_submit_with_failover_execute_layer_orchestrates_filter_and_attempt() -> None:
+    db = MagicMock()
+    svc = TaskService(db)
+    candidate = _make_candidate(provider_id="p2", endpoint_id="e2", key_id="k2")
+
+    prepared = SimpleNamespace(candidates=[candidate], record_map={(0, 0): "rc-1"})
+    outcome = SubmitOutcome(
+        candidate=candidate,  # type: ignore[arg-type]
+        candidate_keys=[{"index": 0, "provider_id": "p2", "selected": True}],
+        external_task_id="task-inner",
+        rule_lookup=None,
+        upstream_payload={"id": "task-inner"},
+        upstream_headers={"x-test": "1"},
+        upstream_status_code=200,
+    )
+
+    svc._submit_ops._prepare_ops.prepare_candidates = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=prepared
+    )
+    svc._submit_ops._execute_ops._filter_ops.build_candidate_info = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value={
+            "index": 0,
+            "provider_id": "p2",
+            "provider_name": "prov",
+            "endpoint_id": "e2",
+            "key_id": "k2",
+            "key_name": "key",
+            "auth_type": "api_key",
+            "priority": 0,
+            "is_cached": False,
+        }
+    )
+    svc._submit_ops._execute_ops._filter_ops.prepare_candidate_for_attempt = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=SimpleNamespace(record_id="rc-1", rule_lookup=None)
+    )
+    svc._submit_ops._execute_ops._attempt_ops.submit_candidate = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=(outcome, 200)
+    )
+
+    result = await svc.submit_with_failover(
+        api_format="openai:video",
+        model_name="sora",
+        affinity_key="a1",
+        user_api_key=MagicMock(user_id="u1"),
+        request_id="rid-2",
+        task_type="video",
+        submit_func=AsyncMock(),
+        extract_external_task_id=lambda payload: payload.get("id"),
+        supported_auth_types={"api_key"},
+        allow_format_conversion=False,
+        max_candidates=10,
+    )
+
+    assert result.external_task_id == "task-inner"
+    svc._submit_ops._execute_ops._filter_ops.build_candidate_info.assert_called_once()  # type: ignore[attr-defined]
+    svc._submit_ops._execute_ops._filter_ops.prepare_candidate_for_attempt.assert_called_once()  # type: ignore[attr-defined]
+    svc._submit_ops._execute_ops._attempt_ops.submit_candidate.assert_awaited_once()  # type: ignore[attr-defined]
+
+
+@pytest.mark.asyncio
+async def test_submit_with_failover_attempt_layer_delegates_to_response_ops() -> None:
+    db = MagicMock()
+    svc = TaskService(db)
+    candidate = _make_candidate(provider_id="p3", endpoint_id="e3", key_id="k3")
+
+    prepared = SimpleNamespace(candidates=[candidate], record_map={(0, 0): "rc-3"})
+    outcome = SubmitOutcome(
+        candidate=candidate,  # type: ignore[arg-type]
+        candidate_keys=[{"index": 0, "provider_id": "p3", "selected": True}],
+        external_task_id="task-attempt",
+        rule_lookup=None,
+        upstream_payload={"id": "task-attempt"},
+        upstream_headers={"x-test": "1"},
+        upstream_status_code=200,
+    )
+
+    svc._submit_ops._prepare_ops.prepare_candidates = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=prepared
+    )
+    svc._submit_ops._execute_ops._filter_ops.build_candidate_info = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value={
+            "index": 0,
+            "provider_id": "p3",
+            "provider_name": "prov3",
+            "endpoint_id": "e3",
+            "key_id": "k3",
+            "key_name": "key3",
+            "auth_type": "api_key",
+            "priority": 0,
+            "is_cached": False,
+        }
+    )
+    svc._submit_ops._execute_ops._filter_ops.prepare_candidate_for_attempt = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=SimpleNamespace(record_id="rc-3", rule_lookup=None)
+    )
+    svc._submit_ops._execute_ops._attempt_ops._record_ops.mark_pending = MagicMock()  # type: ignore[attr-defined, method-assign]
+    svc._submit_ops._execute_ops._attempt_ops._response_ops.handle_submit_response = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=(outcome, 200)
+    )
+
+    submit = AsyncMock(return_value=httpx.Response(200, json={"id": "task-attempt"}))
+
+    result = await svc.submit_with_failover(
+        api_format="openai:video",
+        model_name="sora",
+        affinity_key="a1",
+        user_api_key=MagicMock(user_id="u1"),
+        request_id="rid-3",
+        task_type="video",
+        submit_func=submit,
+        extract_external_task_id=lambda payload: payload.get("id"),
+        supported_auth_types={"api_key"},
+        allow_format_conversion=False,
+        max_candidates=10,
+    )
+
+    assert result.external_task_id == "task-attempt"
+    svc._submit_ops._execute_ops._attempt_ops._record_ops.mark_pending.assert_called_once()  # type: ignore[attr-defined]
+    submit.assert_awaited_once_with(candidate)
+    svc._submit_ops._execute_ops._attempt_ops._response_ops.handle_submit_response.assert_called_once()  # type: ignore[attr-defined]
+
+
+@pytest.mark.asyncio
+async def test_submit_with_failover_response_layer_delegates_to_decider_and_builder() -> None:
+    db = MagicMock()
+    svc = TaskService(db)
+    candidate = _make_candidate(provider_id="p4", endpoint_id="e4", key_id="k4")
+
+    prepared = SimpleNamespace(candidates=[candidate], record_map={(0, 0): "rc-4"})
+    outcome = SubmitOutcome(
+        candidate=candidate,  # type: ignore[arg-type]
+        candidate_keys=[{"index": 0, "provider_id": "p4", "selected": True}],
+        external_task_id="task-response",
+        rule_lookup=None,
+        upstream_payload={"id": "task-response"},
+        upstream_headers={"x-test": "1"},
+        upstream_status_code=200,
+    )
+
+    svc._submit_ops._prepare_ops.prepare_candidates = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=prepared
+    )
+    svc._submit_ops._execute_ops._filter_ops.build_candidate_info = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value={
+            "index": 0,
+            "provider_id": "p4",
+            "provider_name": "prov4",
+            "endpoint_id": "e4",
+            "key_id": "k4",
+            "key_name": "key4",
+            "auth_type": "api_key",
+            "priority": 0,
+            "is_cached": False,
+        }
+    )
+    svc._submit_ops._execute_ops._filter_ops.prepare_candidate_for_attempt = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=SimpleNamespace(record_id="rc-4", rule_lookup=None)
+    )
+    response_ops = svc._submit_ops._execute_ops._attempt_ops._response_ops  # type: ignore[attr-defined]
+    response_ops._rule_decider.detect_error_stop_pattern = MagicMock(return_value=None)  # type: ignore[attr-defined, method-assign]
+    response_ops._rule_decider.detect_success_failover_pattern = MagicMock(return_value=None)  # type: ignore[attr-defined, method-assign]
+    response_ops._outcome_builder.parse_payload = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=SubmitPayloadParseResult(payload={"id": "task-response"})
+    )
+    response_ops._outcome_builder.build_success_outcome = MagicMock(  # type: ignore[attr-defined, method-assign]
+        return_value=outcome
+    )
+
+    submit = AsyncMock(return_value=httpx.Response(200, json={"id": "task-response"}))
+
+    result = await svc.submit_with_failover(
+        api_format="openai:video",
+        model_name="sora",
+        affinity_key="a1",
+        user_api_key=MagicMock(user_id="u1"),
+        request_id="rid-4",
+        task_type="video",
+        submit_func=submit,
+        extract_external_task_id=lambda payload: payload.get("id"),
+        supported_auth_types={"api_key"},
+        allow_format_conversion=False,
+        max_candidates=10,
+    )
+
+    assert result.external_task_id == "task-response"
+    response_ops._rule_decider.detect_error_stop_pattern.assert_not_called()  # type: ignore[attr-defined]
+    response_ops._rule_decider.detect_success_failover_pattern.assert_called_once()  # type: ignore[attr-defined]
+    response_ops._outcome_builder.parse_payload.assert_called_once()  # type: ignore[attr-defined]
+    response_ops._outcome_builder.build_success_outcome.assert_called_once()  # type: ignore[attr-defined]

tests/services/test_failover_engine.py

@@ -1,16 +1,17 @@
-from __future__ import annotations
+from __future__ import annotations
 
 from types import SimpleNamespace
-from typing import Any, AsyncIterator
+from typing import Any, AsyncIterator, cast
 from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
+from src.models.database import Provider, ProviderAPIKey, ProviderEndpoint
 from src.services.candidate.failover import FailoverEngine
 from src.services.candidate.policy import RetryMode, RetryPolicy, SkipPolicy
-from src.services.orchestration.error_classifier import ErrorAction
+from src.services.orchestration.error_classifier import ErrorAction, ErrorClassifier
-from src.services.scheduling.schemas import PoolCandidate
+from src.services.scheduling.schemas import PoolCandidate, ProviderCandidate
-from src.services.task.protocol import AttemptKind, AttemptResult
+from src.services.task.core.protocol import AttemptKind, AttemptResult
 
 
 def _make_candidate(
@@ -28,16 +29,22 @@ def _make_candidate(
     needs_conversion: bool = False,
     provider_max_retries: int | None = None,
     provider_config: dict[str, Any] | None = None,
-) -> SimpleNamespace:
+) -> ProviderCandidate:
-    provider = SimpleNamespace(
+    provider = cast(
+        Provider,
+        SimpleNamespace(
             id=provider_id,
             name=provider_name,
             max_retries=provider_max_retries,
             config=provider_config,
+        ),
     )
-    endpoint = SimpleNamespace(id=endpoint_id)
+    endpoint = cast(ProviderEndpoint, SimpleNamespace(id=endpoint_id))
-    key = SimpleNamespace(id=key_id, name=key_name, auth_type=auth_type, priority=priority)
+    key = cast(
-    return SimpleNamespace(
+        ProviderAPIKey,
+        SimpleNamespace(id=key_id, name=key_name, auth_type=auth_type, priority=priority),
+    )
+    return ProviderCandidate(
         provider=provider,
         endpoint=endpoint,
         key=key,
@@ -62,10 +69,14 @@ class _StubErrorClassifier:
         return self._action
 
 
+def _stub_classifier(*, action: ErrorAction, client_error: bool = False) -> ErrorClassifier:
+    return cast(ErrorClassifier, _StubErrorClassifier(action=action, client_error=client_error))
+
+
 @pytest.mark.asyncio
 async def test_failover_engine_success_first_candidate() -> None:
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     candidates = [_make_candidate(provider_id="p1"), _make_candidate(provider_id="p2")]
 
@@ -97,7 +108,7 @@ async def test_failover_engine_success_first_candidate() -> None:
 @pytest.mark.asyncio
 async def test_failover_engine_continue_to_next_candidate_on_error() -> None:
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     candidates = [_make_candidate(provider_id="p1"), _make_candidate(provider_id="p2")]
 
@@ -132,7 +143,7 @@ async def test_failover_engine_continue_to_next_candidate_on_error() -> None:
 async def test_failover_engine_retry_same_candidate_when_classifier_says_continue() -> None:
     db = MagicMock()
     # ErrorAction.CONTINUE => retry current candidate (mapped to FailoverAction.RETRY)
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.CONTINUE))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.CONTINUE))
 
     candidates = [_make_candidate(provider_id="p1", is_cached=True, provider_max_retries=2)]
 
@@ -167,7 +178,7 @@ async def test_failover_engine_continues_when_classifier_raises() -> None:
     """After the 'default failover' change, RAISE no longer stops failover.
     All candidates should be attempted."""
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.RAISE))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.RAISE))
 
     candidates = [_make_candidate(provider_id="p1"), _make_candidate(provider_id="p2")]
     attempt = AsyncMock(side_effect=RuntimeError("client-ish"))
@@ -200,7 +211,7 @@ async def _empty_stream() -> AsyncIterator[bytes]:
 @pytest.mark.asyncio
 async def test_failover_engine_stream_probe_wraps_first_chunk() -> None:
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     candidates = [_make_candidate(provider_id="p1")]
     attempt = AsyncMock(
@@ -234,7 +245,7 @@ async def test_failover_engine_stream_probe_wraps_first_chunk() -> None:
 @pytest.mark.asyncio
 async def test_failover_engine_stream_probe_empty_triggers_failover() -> None:
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     candidates = [_make_candidate(provider_id="p1"), _make_candidate(provider_id="p2")]
 
@@ -273,7 +284,7 @@ async def test_failover_engine_pre_expand_marks_unused_slots_on_success(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     # patch low-level record updater to observe unused marking
     engine._update_record = MagicMock()  # type: ignore[method-assign]
@@ -333,7 +344,7 @@ class _HttpError(Exception):
 async def test_error_stop_pattern_with_matching_status_code_stops_failover() -> None:
     """When status_codes is set and matches, failover should stop."""
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     config = {
         "failover_rules": {
@@ -376,7 +387,7 @@ async def test_error_stop_pattern_with_matching_status_code_stops_failover() ->
 async def test_error_stop_pattern_with_non_matching_status_code_continues() -> None:
     """When status_codes is set but doesn't match, the rule is skipped and failover continues."""
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     config = {
         "failover_rules": {
@@ -420,7 +431,7 @@ async def test_error_stop_pattern_with_non_matching_status_code_continues() -> N
 async def test_error_stop_pattern_without_status_codes_matches_any() -> None:
     """When status_codes is not set, the rule matches any status code (existing behavior)."""
     db = MagicMock()
-    engine = FailoverEngine(db, error_classifier=_StubErrorClassifier(action=ErrorAction.BREAK))
+    engine = FailoverEngine(db, error_classifier=_stub_classifier(action=ErrorAction.BREAK))
 
     config = {
         "failover_rules": {

tests/services/test_sync_execute_state_transition.py

@@ -0,0 +1,132 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+import pytest
+
+from src.services.candidate.policy import FailoverAction
+from src.services.task.execute.exception_classification import (
+    CandidateErrorAction,
+    classify_candidate_error_action,
+)
+from src.services.task.execute.state_transition import (
+    SyncExecutionState,
+    resolve_execution_error_transition,
+)
+
+
+def _make_candidate() -> SimpleNamespace:
+    return SimpleNamespace(
+        provider=SimpleNamespace(id="p1", name="provider-1"),
+        endpoint=SimpleNamespace(id="e1"),
+        key=SimpleNamespace(id="k1"),
+    )
+
+
+@pytest.mark.parametrize(
+    ("raw_action", "expected"),
+    [
+        ("continue", CandidateErrorAction.RETRY_CURRENT),
+        ("break", CandidateErrorAction.NEXT_CANDIDATE),
+        ("raise", CandidateErrorAction.RAISE_ERROR),
+        ("unexpected", CandidateErrorAction.NEXT_CANDIDATE),
+        (None, CandidateErrorAction.NEXT_CANDIDATE),
+    ],
+)
+def test_classify_candidate_error_action(
+    raw_action: str | None, expected: CandidateErrorAction
+) -> None:
+    assert classify_candidate_error_action(raw_action) == expected
+
+
+def test_resolve_execution_error_transition_retry_and_consume_rectify_flag() -> None:
+    request_body_ref = {"_rectified_this_turn": True}
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=request_body_ref,
+    )
+
+    transition = resolve_execution_error_transition(
+        action=CandidateErrorAction.RETRY_CURRENT,
+        state=state,
+        max_retries_for_candidate=2,
+        retry_index=1,
+    )
+
+    assert transition.failover_action == FailoverAction.RETRY
+    assert transition.max_retries == 3
+    assert request_body_ref["_rectified_this_turn"] is False
+
+
+def test_resolve_execution_error_transition_next_candidate() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref={"_rectified_this_turn": True},
+    )
+
+    transition = resolve_execution_error_transition(
+        action=CandidateErrorAction.NEXT_CANDIDATE,
+        state=state,
+        max_retries_for_candidate=2,
+        retry_index=0,
+    )
+
+    assert transition.failover_action == FailoverAction.CONTINUE
+    assert transition.max_retries is None
+    assert state.request_body_ref == {"_rectified_this_turn": True}
+
+
+def test_sync_execution_state_resolve_candidate_record_id_fallback() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={(2, 0): "r20"},
+        request_body_ref=None,
+    )
+
+    assert state.resolve_candidate_record_id(candidate_index=2, record_id=None) == "r20"
+    assert state.resolve_candidate_record_id(candidate_index=2, record_id="r22") == "r22"
+
+
+def test_sync_execution_state_raise_classified_error_uses_last_error() -> None:
+    err = ValueError("boom")
+    candidate = _make_candidate()
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=None,
+        last_error=err,
+        last_candidate=candidate,
+    )
+    failure_ops = MagicMock()
+
+    with pytest.raises(ValueError, match="boom"):
+        state.raise_classified_error(
+            fallback_error=RuntimeError("fallback"),
+            failure_ops=failure_ops,
+            model_name="gpt-4.1",
+            api_format="openai_chat",
+        )
+
+    failure_ops.attach_metadata_to_error.assert_called_once_with(
+        err,
+        candidate,
+        "gpt-4.1",
+        "openai_chat",
+    )
+
+
+def test_sync_execution_state_raise_classified_error_fallback_error() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=None,
+    )
+    failure_ops = MagicMock()
+
+    with pytest.raises(RuntimeError, match="fallback"):
+        state.raise_classified_error(
+            fallback_error=RuntimeError("fallback"),
+            failure_ops=failure_ops,
+            model_name="gpt-4.1",
+            api_format="openai_chat",
+        )
+
+    failure_ops.attach_metadata_to_error.assert_not_called()

tests/services/test_task_pool_ops.py

@@ -0,0 +1,118 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+from typing import Any, cast
+
+import pytest
+
+from src.models.database import Provider, ProviderAPIKey, ProviderEndpoint
+from src.services.scheduling.schemas import PoolCandidate, ProviderCandidate
+from src.services.task.execute.pool import TaskPoolOperationsService
+
+
+def _provider(provider_id: str) -> Provider:
+    return cast(Provider, SimpleNamespace(id=provider_id))
+
+
+def _endpoint(endpoint_id: str) -> ProviderEndpoint:
+    return cast(ProviderEndpoint, SimpleNamespace(id=endpoint_id))
+
+
+def _key(key_id: str) -> ProviderAPIKey:
+    return cast(ProviderAPIKey, SimpleNamespace(id=key_id))
+
+
+def test_extract_session_uuid_returns_none_for_non_dict_request_body() -> None:
+    svc = TaskPoolOperationsService()
+    assert svc.extract_session_uuid("openai", None) is None
+    assert svc.extract_session_uuid("openai", cast(Any, "not-dict")) is None
+
+
+def test_extract_session_uuid_uses_pool_hook(monkeypatch: pytest.MonkeyPatch) -> None:
+    from src.services.provider.pool import hooks
+
+    hook = SimpleNamespace(extract_session_uuid=lambda body: f"sid:{body.get('session')}")
+
+    def _get_pool_hook(_provider_type: str) -> Any:
+        return hook
+
+    monkeypatch.setattr(hooks, "get_pool_hook", _get_pool_hook)
+
+    svc = TaskPoolOperationsService()
+    session_id = svc.extract_session_uuid("claude_code", {"session": "abc"})
+    assert session_id == "sid:abc"
+
+
+def test_expand_pool_candidates_for_async_submit_keeps_non_pool_candidate() -> None:
+    provider = _provider("p1")
+    endpoint = _endpoint("e1")
+    key = _key("k1")
+    candidate = ProviderCandidate(provider=provider, endpoint=endpoint, key=key)
+
+    svc = TaskPoolOperationsService()
+    expanded = svc.expand_pool_candidates_for_async_submit([candidate])
+
+    assert len(expanded) == 1
+    assert expanded[0] is candidate
+
+
+def test_expand_pool_candidates_for_async_submit_expands_pool_keys() -> None:
+    provider = _provider("p1")
+    endpoint = _endpoint("e1")
+    key = _key("k0")
+    pool_key_1 = cast(
+        ProviderAPIKey,
+        SimpleNamespace(
+            id="k1",
+            _pool_skipped=False,
+            _pool_mapping_matched_model="mapped-model",
+            _pool_extra_data={"source": "warm"},
+        ),
+    )
+    pool_key_2 = cast(
+        ProviderAPIKey,
+        SimpleNamespace(
+            id="k2",
+            _pool_skipped=True,
+            _pool_skip_reason="cooldown",
+            _pool_extra_data={"reason_code": "429"},
+        ),
+    )
+
+    pool_candidate = PoolCandidate(
+        provider=provider,
+        endpoint=endpoint,
+        key=key,
+        is_cached=True,
+        is_skipped=False,
+        skip_reason=None,
+        mapping_matched_model="fallback-model",
+        needs_conversion=True,
+        provider_api_format="openai:chat",
+        output_limit=1024,
+        capability_miss_count=1,
+        pool_keys=[pool_key_1, pool_key_2],
+    )
+
+    svc = TaskPoolOperationsService()
+    expanded = svc.expand_pool_candidates_for_async_submit([pool_candidate])
+
+    assert len(expanded) == 2
+    first, second = expanded
+
+    assert first.key is pool_key_1
+    assert first.is_skipped is False
+    assert first.mapping_matched_model == "mapped-model"
+    first_extra = getattr(first, "_pool_extra_data")
+    assert first_extra["pool_group_id"] == "p1"
+    assert first_extra["pool_key_index"] == 0
+    assert first_extra["source"] == "warm"
+
+    assert second.key is pool_key_2
+    assert second.is_skipped is True
+    assert second.skip_reason == "cooldown"
+    assert second.mapping_matched_model == "fallback-model"
+    second_extra = getattr(second, "_pool_extra_data")
+    assert second_extra["pool_group_id"] == "p1"
+    assert second_extra["pool_key_index"] == 1
+    assert second_extra["reason_code"] == "429"

tests/services/test_task_service_async_execute.py

@@ -1,4 +1,4 @@
-from __future__ import annotations
+from __future__ import annotations
 
 from types import SimpleNamespace
 from unittest.mock import AsyncMock, MagicMock
@@ -8,10 +8,9 @@ import pytest
 from src.core.exceptions import EmbeddedErrorException
 from src.services.candidate.schema import CandidateKey
 from src.services.candidate.submit import SubmitOutcome
-from src.services.request.executor import ExecutionContext, ExecutionError
+from src.services.task.core.context import TaskMode
-from src.services.task import service as task_service_module
+from src.services.task.core.protocol import AttemptKind
-from src.services.task.context import TaskMode
+from src.services.task.service import pool_on_error
-from src.services.task.protocol import AttemptKind
 from src.services.task.service import TaskService
 
 
@@ -51,7 +50,7 @@ async def test_task_service_execute_async_returns_execution_result() -> None:
     )
 
     svc.submit_with_failover = AsyncMock(return_value=outcome)  # type: ignore[method-assign]
-    svc._recorder.get_candidate_keys = MagicMock(  # type: ignore[attr-defined, method-assign]
+    svc._execute_facade_ops._get_candidate_keys = MagicMock(  # type: ignore[attr-defined, method-assign]
         return_value=[
             CandidateKey(candidate_index=0, retry_index=0, status="success", provider_id="p1")
         ]
@@ -82,7 +81,7 @@ async def test_task_service_execute_sync_passes_request_headers_and_body() -> No
     db = MagicMock()
     svc = TaskService(db)
     sentinel_result = object()
-    svc._execute_sync_unified = AsyncMock(  # type: ignore[method-assign]
+    svc._sync_ops.execute_sync_unified = AsyncMock(  # type: ignore[attr-defined, method-assign]
         return_value=sentinel_result
     )
 
@@ -105,95 +104,92 @@ async def test_task_service_execute_sync_passes_request_headers_and_body() -> No
     )
 
     assert result is sentinel_result
-    svc._execute_sync_unified.assert_awaited_once()  # type: ignore[attr-defined]
+    svc._sync_ops.execute_sync_unified.assert_awaited_once()  # type: ignore[attr-defined]
-    kwargs = svc._execute_sync_unified.await_args.kwargs  # type: ignore[attr-defined, union-attr]
+    kwargs = svc._sync_ops.execute_sync_unified.await_args.kwargs  # type: ignore[attr-defined, union-attr]
     assert kwargs["request_headers"] == request_headers
     assert kwargs["request_body"] == request_body
     assert kwargs["request_body_ref"] == request_body_ref
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize(
+async def test_task_service_execute_delegates_to_execute_facade_ops() -> None:
-    ("is_client_error", "retry_index", "max_retries_for_candidate", "expected_action"),
+    svc = TaskService(MagicMock())
-    [
+    sentinel = object()
-        (True, 0, 1, "break"),
+    svc._execute_facade_ops.execute = AsyncMock(return_value=sentinel)  # type: ignore[attr-defined, method-assign]
-        (False, 0, 2, "continue"),
-    ],
-)
-async def test_task_service_embedded_error_branch_applies_pool_health_policy(
-    monkeypatch: pytest.MonkeyPatch,
-    is_client_error: bool,
-    retry_index: int,
-    max_retries_for_candidate: int,
-    expected_action: str,
-) -> None:
-    db = MagicMock()
-    svc = TaskService(db)
 
-    monkeypatch.setattr(
+    result = await svc.execute(
-        task_service_module.RequestCandidateService, "mark_candidate_failed", MagicMock()
+        task_type="chat",
-    )
+        task_mode=TaskMode.SYNC,
-    monkeypatch.setattr(
-        "src.services.proxy_node.resolver.resolve_effective_proxy",
-        lambda provider_proxy, key_proxy: provider_proxy or key_proxy,
-    )
-    monkeypatch.setattr("src.services.proxy_node.resolver.resolve_proxy_info", lambda _proxy: None)
-
-    pool_on_error = AsyncMock()
-    monkeypatch.setattr(svc, "_pool_on_error", pool_on_error)
-
-    candidate = SimpleNamespace(
-        provider=SimpleNamespace(id="p1", name="prov", proxy=None),
-        endpoint=SimpleNamespace(id="e1"),
-        key=SimpleNamespace(id="k1", proxy=None),
-    )
-    cause = EmbeddedErrorException(
-        provider_name="prov",
-        error_code=429,
-        error_message="usage_limit_reached",
-        error_status="RESOURCE_EXHAUSTED",
-    )
-    context = ExecutionContext(
-        candidate_id="cid-1",
-        candidate_index=0,
-        provider_id="p1",
-        endpoint_id="e1",
-        key_id="k1",
-        user_id=None,
-        api_key_id=None,
-        is_cached_user=False,
-        elapsed_ms=12,
-        concurrent_requests=3,
-    )
-    exec_err = ExecutionError(cause, context)
-    classifier = SimpleNamespace(is_client_error=lambda _text: is_client_error)
-
-    action = await svc._handle_candidate_error(
-        exec_err=exec_err,
-        candidate=candidate,
-        candidate_record_id="cand-1",
-        retry_index=retry_index,
-        max_retries_for_candidate=max_retries_for_candidate,
-        affinity_key="provider-test:p1",
         api_format="openai:chat",
-        global_model_id="gpt-4o-mini",
+        model_name="m",
-        request_id="req-1",
+        user_api_key=MagicMock(id="u", user_id="user"),
-        attempt=1,
+        request_func=AsyncMock(),
-        max_attempts=3,
+        request_id="rid",
-        error_classifier=classifier,
     )
 
-    assert action == expected_action
+    assert result is sentinel
-    pool_on_error.assert_awaited_once_with(candidate.provider, candidate.key, 429, cause)
+    svc._execute_facade_ops.execute.assert_awaited_once()  # type: ignore[attr-defined]
 
 
 @pytest.mark.asyncio
-async def test_task_service_pool_on_error_uses_embedded_error_message_fallback(
+async def test_task_service_submit_with_failover_delegates_to_submit_facade_ops() -> None:
+    svc = TaskService(MagicMock())
+    sentinel = object()
+    svc._submit_facade_ops.submit_with_failover = AsyncMock(  # type: ignore[attr-defined, method-assign]
+        return_value=sentinel
+    )
+
+    result = await svc.submit_with_failover(
+        api_format="openai:video",
+        model_name="sora",
+        affinity_key="a1",
+        user_api_key=MagicMock(id="u", user_id="user"),
+        request_id="rid",
+        task_type="video",
+        submit_func=AsyncMock(),
+        extract_external_task_id=lambda payload: payload.get("id"),
+    )
+
+    assert result is sentinel
+    svc._submit_facade_ops.submit_with_failover.assert_awaited_once()  # type: ignore[attr-defined]
+
+
+@pytest.mark.asyncio
+async def test_task_service_poll_delegates_to_video_facade_ops() -> None:
+    svc = TaskService(MagicMock())
+    sentinel = object()
+    svc._video_facade_ops.poll = AsyncMock(return_value=sentinel)  # type: ignore[attr-defined, method-assign]
+
+    result = await svc.poll("task-1", user_id="user-1")
+
+    assert result is sentinel
+    svc._video_facade_ops.poll.assert_awaited_once_with("task-1", user_id="user-1")  # type: ignore[attr-defined]
+
+
+@pytest.mark.asyncio
+async def test_task_service_cancel_delegates_to_video_facade_ops() -> None:
+    svc = TaskService(MagicMock())
+    sentinel = object()
+    svc._video_facade_ops.cancel = AsyncMock(return_value=sentinel)  # type: ignore[attr-defined, method-assign]
+
+    result = await svc.cancel(
+        "task-1",
+        user_id="user-1",
+        original_headers={"x-test": "1"},
+    )
+
+    assert result is sentinel
+    svc._video_facade_ops.cancel.assert_awaited_once_with(  # type: ignore[attr-defined]
+        "task-1",
+        user_id="user-1",
+        original_headers={"x-test": "1"},
+    )
+
+
+@pytest.mark.asyncio
+async def test_pool_on_error_uses_embedded_error_message_fallback(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
-    db = MagicMock()
-    svc = TaskService(db)
-
     parsed_pool_cfg = object()
     apply_health_policy = AsyncMock()
     monkeypatch.setattr(
@@ -212,7 +208,7 @@ async def test_task_service_pool_on_error_uses_embedded_error_message_fallback(
         error_message="usage_limit_reached",
     )
 
-    await svc._pool_on_error(provider, key, 429, cause)
+    await pool_on_error(provider, key, 429, cause)
 
     apply_health_policy.assert_awaited_once()
     kwargs = apply_health_policy.await_args.kwargs

tests/services/test_video_ops_cancel_delegate.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+from fastapi import HTTPException
+
+from src.services.task.core.exceptions import TaskNotFoundError
+from src.services.task.video.operations import VideoTaskOperationsService
+
+
+@pytest.mark.asyncio
+async def test_video_ops_cancel_delegates_to_cancel_ops() -> None:
+    svc = VideoTaskOperationsService(MagicMock())
+    task = SimpleNamespace(id="task-1")
+
+    svc._get_video_task_for_user = MagicMock(return_value=task)  # type: ignore[attr-defined, method-assign]
+    svc._cancel_ops.cancel_task = AsyncMock(return_value={"ok": True})  # type: ignore[attr-defined, method-assign]
+
+    result = await svc.cancel(
+        "task-1",
+        user_id="user-1",
+        original_headers={"x-test": "1"},
+    )
+
+    assert result == {"ok": True}
+    svc._cancel_ops.cancel_task.assert_awaited_once_with(  # type: ignore[attr-defined]
+        task=task,
+        task_id="task-1",
+        original_headers={"x-test": "1"},
+    )
+
+
+@pytest.mark.asyncio
+async def test_video_ops_cancel_maps_not_found_to_http_404() -> None:
+    svc = VideoTaskOperationsService(MagicMock())
+    svc._get_video_task_for_user = MagicMock(side_effect=TaskNotFoundError("missing"))  # type: ignore[attr-defined, method-assign]
+
+    with pytest.raises(HTTPException) as excinfo:
+        await svc.cancel("missing", user_id="user-1")
+
+    assert excinfo.value.status_code == 404
+    assert excinfo.value.detail == "Video task not found"

tests/services/test_video_task_poller.py

@@ -1,10 +1,12 @@
-from types import SimpleNamespace
+from types import SimpleNamespace
+from typing import cast
 from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
 from src.core.api_format.conversion.internal_video import InternalVideoPollResult, VideoStatus
-from src.services.task.impl.video_poller import VideoTaskPollerAdapter
+from src.models.database import VideoTask
+from src.services.task.video.poller_adapter import VideoTaskPollerAdapter
 
 
 @pytest.mark.asyncio
@@ -13,11 +15,14 @@ async def test_poll_task_status_routes_gemini_video_to_gemini(
 ) -> None:
     adapter = VideoTaskPollerAdapter()
 
-    task = SimpleNamespace(
+    task = cast(
+        VideoTask,
+        SimpleNamespace(
             endpoint_id="e1",
             key_id="k1",
             provider_api_format="gemini:video",
             external_task_id="operations/123",
+        ),
     )
     endpoint = SimpleNamespace(id="e1", base_url="https://example.com", api_format="gemini:video")
     key = SimpleNamespace(id="k1", api_key="enc")
@@ -25,12 +30,12 @@ async def test_poll_task_status_routes_gemini_video_to_gemini(
     monkeypatch.setattr(adapter, "_get_endpoint", lambda _db, _id: endpoint)
     monkeypatch.setattr(adapter, "_get_key", lambda _db, _id: key)
     monkeypatch.setattr(
-        "src.services.task.impl.video_poller.crypto_service.decrypt", lambda _v: "decrypted"
+        "src.services.task.video.poller_adapter.crypto_service.decrypt", lambda _v: "decrypted"
     )
 
     auth_info = SimpleNamespace(auth_header="authorization", auth_value="Bearer x")
     monkeypatch.setattr(
-        "src.services.task.impl.video_poller.get_provider_auth",
+        "src.services.task.video.poller_adapter.get_provider_auth",
         AsyncMock(return_value=auth_info),
     )