feat(experts):恢复 plan.py 阶段依赖图 (PlanPhase + topological_sort)

- 新增 PhaseStatus 枚举 (PENDING/RUNNING/COMPLETED/FAILED)
- 新增 PlanPhase 数据类 (id/name/assigned_expert/task_description/depends_on/status/result)
- TeamPlan 新增 phases 字段及配套方法: get_phase/update_phase_status/topological_sort/get_ready_phases
- topological_sort 使用 Kahn 算法返回执行层 (list[list[PlanPhase]])，检测循环依赖
- 保留 SubTask/MergeStrategy 向后兼容
- 新增 54 个单元测试覆盖线性/并行/循环依赖、无效引用、就绪阶段、序列化

src/agentkit/experts/plan.py

@@ -1,11 +1,13 @@
-"""Expert Team 计划数据模型 - hub-and-spoke 模式
+"""Expert Team 计划数据模型 - 流水线模式
 
-简化为 Lead Expert + 并行 Task 模式：
-- Lead Expert 接收任务并分解为子任务
-- 子任务并行执行（Task 深度=1，不能再 spawn Task）
-- Lead Expert 汇总结果（BEST 策略）
+支持两种模式：
+1. hub-and-spoke（向后兼容）：Lead Expert 分解为并行子任务（SubTask）
+2. pipeline（新）：Lead Expert 分解为阶段（PlanPhase），阶段间有依赖关系
 
-移除了阶段依赖图、VOTE/FUSION 合并策略、跨阶段状态共享。
+流水线模式核心：
+- Lead Expert 分解任务为阶段（phases），每个阶段有 assigned_expert 和 depends_on
+- 执行时按依赖拓扑排序，无依赖的阶段并行，有依赖的串行
+- 阶段间数据通过 SharedWorkspace 传递
 """
 
 from __future__ import annotations
@@ -19,8 +21,7 @@ from typing import Any
 class MergeStrategy(str, enum.Enum):
     """合并策略 - Lead Expert 用于选择最佳结果
 
-    hub-and-spoke 模式下仅保留 BEST 策略：
-    Lead Expert 从所有子任务结果中选择或综合出最佳结果。
+    仅保留 BEST 策略：Lead Expert 从所有结果中选择或综合出最佳结果。
     """
 
     BEST = "best"
@@ -37,7 +38,16 @@ class PlanStatus(str, enum.Enum):
 
 
 class SubTaskStatus(str, enum.Enum):
-    """子任务状态"""
+    """子任务状态（hub-and-spoke 模式）"""
+
+    PENDING = "pending"
+    RUNNING = "running"
+    COMPLETED = "completed"
+    FAILED = "failed"
+
+
+class PhaseStatus(str, enum.Enum):
+    """阶段状态（流水线模式）"""
 
     PENDING = "pending"
     RUNNING = "running"
@@ -47,15 +57,7 @@ class SubTaskStatus(str, enum.Enum):
 
 @dataclass
 class SubTask:
-    """Lead Expert 分解出的子任务
-
-    在 hub-and-spoke 模式中，Lead Expert 将原始任务分解为多个子任务，
-    每个子任务由一个 Expert 并行执行。子任务之间无依赖关系、无通信。
-
-    约束：
-    - Task 深度=1（子任务不能再 spawn 子任务）
-    - 子任务之间无通信
-    - Lead Expert 持有所有状态
+    """Lead Expert 分解出的子任务（hub-and-spoke 模式，向后兼容）
 
     Attributes:
         id: 子任务标识符
@@ -94,17 +96,71 @@ class SubTask:
 
 
 @dataclass
-class TeamPlan:
-    """Expert Team hub-and-spoke 执行计划
+class PlanPhase:
+    """流水线模式中的执行阶段
 
-    Lead Expert 持有此计划，包含分解的子任务列表。
-    与旧版 CollaborationPlan 不同，此计划无阶段依赖图，
-    所有子任务并行执行，由 Lead Expert 统一汇总。
+    Lead Expert 将任务分解为多个阶段，阶段间通过 depends_on 建立依赖关系。
+    执行时按拓扑排序，同层无依赖阶段并行，层间串行。
+
+    Attributes:
+        id: 阶段标识符（用于 depends_on 引用）
+        name: 阶段名称（如"规划"、"前端"、"后端"、"QA"、"评审"）
+        assigned_expert: 分配的 Expert 名称
+        task_description: 阶段任务描述
+        depends_on: 前置阶段 ID 列表（空列表表示无依赖）
+        status: 当前状态
+        result: 阶段输出结果
+    """
+
+    id: str = field(default_factory=lambda: str(uuid.uuid4()))
+    name: str = ""
+    assigned_expert: str = ""
+    task_description: str = ""
+    depends_on: list[str] = field(default_factory=list)
+    status: PhaseStatus = PhaseStatus.PENDING
+    result: dict[str, Any] | None = None
+
+    def to_dict(self) -> dict[str, Any]:
+        """序列化为字典"""
+        return {
+            "id": self.id,
+            "name": self.name,
+            "assigned_expert": self.assigned_expert,
+            "task_description": self.task_description,
+            "depends_on": list(self.depends_on),
+            "status": self.status.value,
+            "result": self.result,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> PlanPhase:
+        """从字典创建 PlanPhase"""
+        return cls(
+            id=data.get("id", str(uuid.uuid4())),
+            name=data.get("name", ""),
+            assigned_expert=data.get("assigned_expert", ""),
+            task_description=data.get("task_description", ""),
+            depends_on=list(data.get("depends_on", [])),
+            status=PhaseStatus(data.get("status", PhaseStatus.PENDING.value)),
+            result=data.get("result"),
+        )
+
+
+@dataclass
+class TeamPlan:
+    """Expert Team 执行计划
+
+    支持两种模式：
+    1. hub-and-spoke（向后兼容）：使用 subtasks，并行执行无依赖
+    2. pipeline（新）：使用 phases，按依赖拓扑排序执行
+
+    新代码应优先使用 phases 字段。subtasks 保留用于向后兼容。
 
     Attributes:
         id: 计划标识符
         task: 原始任务描述
-        subtasks: 子任务列表（并行执行，无依赖关系）
+        subtasks: 子任务列表（hub-and-spoke 模式，向后兼容）
+        phases: 阶段列表（流水线模式）
         status: 计划状态
         lead_expert: 主导 Expert 名称
     """
@@ -112,6 +168,7 @@ class TeamPlan:
     id: str = field(default_factory=lambda: str(uuid.uuid4()))
     task: str = ""
     subtasks: list[SubTask] = field(default_factory=list)
+    phases: list[PlanPhase] = field(default_factory=list)
     status: PlanStatus = PlanStatus.DRAFT
     lead_expert: str = ""
 
@@ -121,6 +178,7 @@ class TeamPlan:
             "id": self.id,
             "task": self.task,
             "subtasks": [st.to_dict() for st in self.subtasks],
+            "phases": [ph.to_dict() for ph in self.phases],
             "status": self.status.value,
             "lead_expert": self.lead_expert,
         }
@@ -129,14 +187,18 @@ class TeamPlan:
     def from_dict(cls, data: dict[str, Any]) -> TeamPlan:
         """从字典创建 TeamPlan"""
         subtasks = [SubTask.from_dict(st) for st in data.get("subtasks", [])]
+        phases = [PlanPhase.from_dict(ph) for ph in data.get("phases", [])]
         return cls(
             id=data.get("id", str(uuid.uuid4())),
             task=data.get("task", ""),
             subtasks=subtasks,
+            phases=phases,
             status=PlanStatus(data.get("status", PlanStatus.DRAFT.value)),
             lead_expert=data.get("lead_expert", ""),
         )
 
+    # ── SubTask 方法（hub-and-spoke 模式，向后兼容）──
+
     def get_subtask(self, subtask_id: str) -> SubTask | None:
         """根据 ID 获取子任务，不存在则返回 None"""
         for st in self.subtasks:
@@ -170,3 +232,121 @@ class TeamPlan:
         return all(
             st.status in (SubTaskStatus.COMPLETED, SubTaskStatus.FAILED) for st in self.subtasks
         )
+
+    # ── PlanPhase 方法（流水线模式）──
+
+    def get_phase(self, phase_id: str) -> PlanPhase | None:
+        """根据 ID 获取阶段，不存在则返回 None"""
+        for ph in self.phases:
+            if ph.id == phase_id:
+                return ph
+        return None
+
+    def update_phase_status(
+        self, phase_id: str, status: PhaseStatus, result: dict[str, Any] | None = None
+    ) -> None:
+        """更新阶段状态和可选的结果"""
+        ph = self.get_phase(phase_id)
+        if ph is not None:
+            ph.status = status
+            if result is not None:
+                ph.result = result
+
+    @property
+    def completed_phases(self) -> list[PlanPhase]:
+        """已完成的阶段列表"""
+        return [ph for ph in self.phases if ph.status == PhaseStatus.COMPLETED]
+
+    @property
+    def failed_phases(self) -> list[PlanPhase]:
+        """失败的阶段列表"""
+        return [ph for ph in self.phases if ph.status == PhaseStatus.FAILED]
+
+    @property
+    def all_phases_done(self) -> bool:
+        """所有阶段是否都已完成（成功或失败）"""
+        return all(
+            ph.status in (PhaseStatus.COMPLETED, PhaseStatus.FAILED) for ph in self.phases
+        )
+
+    def get_ready_phases(self) -> list[PlanPhase]:
+        """返回当前可执行的阶段（状态为 PENDING 且所有依赖已完成）
+
+        Returns:
+            可执行的阶段列表
+        """
+        completed_ids = {ph.id for ph in self.completed_phases}
+        ready = []
+        for ph in self.phases:
+            if ph.status != PhaseStatus.PENDING:
+                continue
+            # Check if all dependencies are completed
+            if all(dep_id in completed_ids for dep_id in ph.depends_on):
+                ready.append(ph)
+        return ready
+
+    def topological_sort(self) -> list[list[PlanPhase]]:
+        """按依赖关系拓扑排序阶段，返回执行层列表
+
+        同层阶段无依赖关系，可并行执行；层间有依赖，需串行等待。
+
+        Returns:
+            执行层列表，每层包含可并行执行的阶段
+
+        Raises:
+            ValueError: 如果存在循环依赖
+        """
+        if not self.phases:
+            return []
+
+        # Build dependency graph
+        phase_map = {ph.id: ph for ph in self.phases}
+        all_ids = set(phase_map.keys())
+
+        # Validate depends_on references
+        for ph in self.phases:
+            for dep_id in ph.depends_on:
+                if dep_id not in all_ids:
+                    raise ValueError(
+                        f"Phase '{ph.id}' ({ph.name}) depends on non-existent phase '{dep_id}'"
+                    )
+
+        # Kahn's algorithm for topological sort
+        # Compute in-degree (number of dependencies) for each phase
+        in_degree: dict[str, int] = {ph.id: len(ph.depends_on) for ph in self.phases}
+
+        # Build reverse dependency map (which phases depend on this one)
+        dependents: dict[str, list[str]] = {ph.id: [] for ph in self.phases}
+        for ph in self.phases:
+            for dep_id in ph.depends_on:
+                dependents[dep_id].append(ph.id)
+
+        layers: list[list[PlanPhase]] = []
+        processed: set[str] = set()
+
+        while len(processed) < len(self.phases):
+            # Find all phases with in_degree 0 that haven't been processed
+            current_layer_ids = [
+                ph_id
+                for ph_id in in_degree
+                if ph_id not in processed and in_degree[ph_id] == 0
+            ]
+
+            if not current_layer_ids:
+                # No progress — cycle detected
+                remaining = [ph_id for ph_id in in_degree if ph_id not in processed]
+                raise ValueError(
+                    f"Circular dependency detected among phases: {remaining}"
+                )
+
+            # Add current layer
+            current_layer = [phase_map[ph_id] for ph_id in current_layer_ids]
+            layers.append(current_layer)
+
+            # Mark as processed and reduce in_degree for dependents
+            for ph_id in current_layer_ids:
+                processed.add(ph_id)
+                for dep_id in dependents[ph_id]:
+                    in_degree[dep_id] -= 1
+
+        return layers

tests/unit/experts/test_plan.py

@@ -1,9 +1,13 @@
-"""TeamPlan / SubTask 数据模型单元测试 (hub-and-spoke 模式)"""
+"""TeamPlan / SubTask / PlanPhase 数据模型单元测试 (hub-and-spoke + 流水线模式)"""
 
 from __future__ import annotations
 
+import pytest
+
 from agentkit.experts.plan import (
     MergeStrategy,
+    PhaseStatus,
+    PlanPhase,
     PlanStatus,
     SubTask,
     SubTaskStatus,
@@ -286,3 +290,426 @@ class TestTeamPlan:
         """all_done 当没有子任务时返回 True（vacuous truth）"""
         plan = TeamPlan(task="空计划")
         assert plan.all_done is True
+
+
+# ── PlanPhase 测试（流水线模式）──────────────────────────
+
+
+def _make_phase(
+    id: str = "phase_1",
+    name: str = "规划",
+    assigned_expert: str = "tech_lead",
+    task_description: str = "分析需求并制定计划",
+    depends_on: list[str] | None = None,
+    status: PhaseStatus = PhaseStatus.PENDING,
+    result: dict | None = None,
+) -> PlanPhase:
+    """创建测试用 PlanPhase 实例"""
+    return PlanPhase(
+        id=id,
+        name=name,
+        assigned_expert=assigned_expert,
+        task_description=task_description,
+        depends_on=depends_on or [],
+        status=status,
+        result=result,
+    )
+
+
+def _make_pipeline_plan() -> TeamPlan:
+    """创建一个流水线模式的执行计划
+
+    结构:
+        Layer 0: [规划] (无依赖)
+        Layer 1: [前端, 后端] (依赖规划)
+        Layer 2: [QA] (依赖前端+后端)
+        Layer 3: [评审] (依赖QA)
+    """
+    phases = [
+        _make_phase(id="p1", name="规划", assigned_expert="tech_lead", depends_on=[]),
+        _make_phase(
+            id="p2", name="前端", assigned_expert="frontend_engineer", depends_on=["p1"]
+        ),
+        _make_phase(
+            id="p3", name="后端", assigned_expert="backend_engineer", depends_on=["p1"]
+        ),
+        _make_phase(id="p4", name="QA", assigned_expert="qa_engineer", depends_on=["p2", "p3"]),
+        _make_phase(id="p5", name="评审", assigned_expert="code_reviewer", depends_on=["p4"]),
+    ]
+    return TeamPlan(
+        id="pipeline_001",
+        task="开发用户登录功能",
+        phases=phases,
+        status=PlanStatus.DRAFT,
+        lead_expert="tech_lead",
+    )
+
+
+class TestPhaseStatus:
+    """PhaseStatus 枚举测试"""
+
+    def test_statuses_exist(self):
+        """阶段状态都存在"""
+        assert PhaseStatus.PENDING == "pending"
+        assert PhaseStatus.RUNNING == "running"
+        assert PhaseStatus.COMPLETED == "completed"
+        assert PhaseStatus.FAILED == "failed"
+
+
+class TestPlanPhase:
+    """PlanPhase 数据模型测试"""
+
+    def test_creation_with_all_fields(self):
+        """创建 PlanPhase 并设置所有字段"""
+        phase = PlanPhase(
+            id="phase_a",
+            name="前端开发",
+            assigned_expert="frontend_engineer",
+            task_description="实现登录页面",
+            depends_on=["phase_planning"],
+            status=PhaseStatus.RUNNING,
+            result={"component": "LoginForm"},
+        )
+        assert phase.id == "phase_a"
+        assert phase.name == "前端开发"
+        assert phase.assigned_expert == "frontend_engineer"
+        assert phase.task_description == "实现登录页面"
+        assert phase.depends_on == ["phase_planning"]
+        assert phase.status == PhaseStatus.RUNNING
+        assert phase.result == {"component": "LoginForm"}
+
+    def test_default_values(self):
+        """默认值：自动生成 id，空 depends_on，PENDING 状态"""
+        phase = PlanPhase(name="测试阶段")
+        assert phase.id is not None
+        assert len(phase.id) > 0
+        assert phase.name == "测试阶段"
+        assert phase.assigned_expert == ""
+        assert phase.task_description == ""
+        assert phase.depends_on == []
+        assert phase.status == PhaseStatus.PENDING
+        assert phase.result is None
+
+    def test_to_dict_from_dict_roundtrip(self):
+        """to_dict / from_dict 往返序列化"""
+        phase = _make_phase(
+            id="roundtrip_phase",
+            name="往返测试",
+            assigned_expert="tester",
+            task_description="测试序列化",
+            depends_on=["dep1", "dep2"],
+            status=PhaseStatus.COMPLETED,
+            result={"key": "value"},
+        )
+        d = phase.to_dict()
+        restored = PlanPhase.from_dict(d)
+
+        assert restored.id == phase.id
+        assert restored.name == phase.name
+        assert restored.assigned_expert == phase.assigned_expert
+        assert restored.task_description == phase.task_description
+        assert restored.depends_on == phase.depends_on
+        assert restored.status == phase.status
+        assert restored.result == phase.result
+
+    def test_to_dict_structure(self):
+        """to_dict 返回正确的字典结构"""
+        phase = _make_phase(
+            id="struct_test",
+            name="结构测试",
+            assigned_expert="dev",
+            task_description="测试结构",
+            depends_on=["d1"],
+            status=PhaseStatus.RUNNING,
+            result={"output": "data"},
+        )
+        d = phase.to_dict()
+        assert d["id"] == "struct_test"
+        assert d["name"] == "结构测试"
+        assert d["assigned_expert"] == "dev"
+        assert d["task_description"] == "测试结构"
+        assert d["depends_on"] == ["d1"]
+        assert d["status"] == "running"
+        assert d["result"] == {"output": "data"}
+
+
+class TestTeamPlanPhases:
+    """TeamPlan 流水线模式（phases）测试"""
+
+    def test_pipeline_plan_creation(self):
+        """创建流水线模式的 TeamPlan"""
+        plan = _make_pipeline_plan()
+        assert plan.id == "pipeline_001"
+        assert plan.task == "开发用户登录功能"
+        assert len(plan.phases) == 5
+        assert plan.lead_expert == "tech_lead"
+
+    def test_get_phase_by_id(self):
+        """get_phase 根据 ID 获取阶段"""
+        plan = _make_pipeline_plan()
+        ph = plan.get_phase("p3")
+        assert ph is not None
+        assert ph.id == "p3"
+        assert ph.name == "后端"
+
+    def test_get_phase_nonexistent_returns_none(self):
+        """get_phase 对不存在的 ID 返回 None"""
+        plan = _make_pipeline_plan()
+        assert plan.get_phase("nonexistent") is None
+
+    def test_update_phase_status(self):
+        """update_phase_status 更新阶段状态和结果"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED, {"plan": "设计文档"})
+        ph = plan.get_phase("p1")
+        assert ph is not None
+        assert ph.status == PhaseStatus.COMPLETED
+        assert ph.result == {"plan": "设计文档"}
+
+    def test_update_phase_status_without_result(self):
+        """update_phase_status 不传 result 时不覆盖已有 result"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED, {"plan": "文档"})
+        plan.update_phase_status("p1", PhaseStatus.RUNNING)
+        ph = plan.get_phase("p1")
+        assert ph is not None
+        assert ph.status == PhaseStatus.RUNNING
+        assert ph.result == {"plan": "文档"}
+
+    def test_completed_phases_property(self):
+        """completed_phases 返回已完成的阶段"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p2", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p3", PhaseStatus.FAILED)
+
+        completed = plan.completed_phases
+        assert len(completed) == 2
+        assert {ph.id for ph in completed} == {"p1", "p2"}
+
+    def test_failed_phases_property(self):
+        """failed_phases 返回失败的阶段"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p2", PhaseStatus.FAILED)
+        plan.update_phase_status("p3", PhaseStatus.FAILED)
+
+        failed = plan.failed_phases
+        assert len(failed) == 2
+        assert {ph.id for ph in failed} == {"p2", "p3"}
+
+    def test_all_phases_done_when_all_completed(self):
+        """all_phases_done 当所有阶段完成时返回 True"""
+        plan = _make_pipeline_plan()
+        for ph in plan.phases:
+            plan.update_phase_status(ph.id, PhaseStatus.COMPLETED)
+        assert plan.all_phases_done is True
+
+    def test_all_phases_done_when_some_failed(self):
+        """all_phases_done 当所有阶段完成或失败时返回 True"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p2", PhaseStatus.FAILED)
+        plan.update_phase_status("p3", PhaseStatus.FAILED)
+        plan.update_phase_status("p4", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p5", PhaseStatus.COMPLETED)
+        assert plan.all_phases_done is True
+
+    def test_all_phases_done_when_pending(self):
+        """all_phases_done 当有阶段未完成时返回 False"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        # p2-p5 still pending
+        assert plan.all_phases_done is False
+
+    def test_all_phases_done_empty_plan(self):
+        """all_phases_done 当没有阶段时返回 True"""
+        plan = TeamPlan(task="空计划")
+        assert plan.all_phases_done is True
+
+
+class TestTopologicalSort:
+    """topological_sort 拓扑排序测试"""
+
+    def test_linear_dependency(self):
+        """线性依赖：A→B→C 排序为 [[A], [B], [C]]"""
+        plan = TeamPlan(
+            task="线性任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=[]),
+                _make_phase(id="b", name="B", depends_on=["a"]),
+                _make_phase(id="c", name="C", depends_on=["b"]),
+            ],
+        )
+        layers = plan.topological_sort()
+        assert len(layers) == 3
+        assert [ph.id for ph in layers[0]] == ["a"]
+        assert [ph.id for ph in layers[1]] == ["b"]
+        assert [ph.id for ph in layers[2]] == ["c"]
+
+    def test_parallel_phases(self):
+        """并行阶段：A→{B,C}→D 排序为 [[A], [B,C], [D]]"""
+        plan = TeamPlan(
+            task="并行任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=[]),
+                _make_phase(id="b", name="B", depends_on=["a"]),
+                _make_phase(id="c", name="C", depends_on=["a"]),
+                _make_phase(id="d", name="D", depends_on=["b", "c"]),
+            ],
+        )
+        layers = plan.topological_sort()
+        assert len(layers) == 3
+        assert [ph.id for ph in layers[0]] == ["a"]
+        assert set(ph.id for ph in layers[1]) == {"b", "c"}
+        assert [ph.id for ph in layers[2]] == ["d"]
+
+    def test_full_pipeline_structure(self):
+        """完整流水线结构：规划→{前端,后端}→QA→评审"""
+        plan = _make_pipeline_plan()
+        layers = plan.topological_sort()
+        assert len(layers) == 4
+        assert [ph.id for ph in layers[0]] == ["p1"]
+        assert set(ph.id for ph in layers[1]) == {"p2", "p3"}
+        assert [ph.id for ph in layers[2]] == ["p4"]
+        assert [ph.id for ph in layers[3]] == ["p5"]
+
+    def test_no_dependencies(self):
+        """无依赖：所有阶段在同一层"""
+        plan = TeamPlan(
+            task="无依赖任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=[]),
+                _make_phase(id="b", name="B", depends_on=[]),
+                _make_phase(id="c", name="C", depends_on=[]),
+            ],
+        )
+        layers = plan.topological_sort()
+        assert len(layers) == 1
+        assert set(ph.id for ph in layers[0]) == {"a", "b", "c"}
+
+    def test_empty_phases(self):
+        """空阶段列表返回空列表"""
+        plan = TeamPlan(task="空计划")
+        assert plan.topological_sort() == []
+
+    def test_circular_dependency_raises(self):
+        """循环依赖 A→B→A 抛出 ValueError"""
+        plan = TeamPlan(
+            task="循环依赖任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=["b"]),
+                _make_phase(id="b", name="B", depends_on=["a"]),
+            ],
+        )
+        with pytest.raises(ValueError, match="Circular dependency"):
+            plan.topological_sort()
+
+    def test_self_dependency_raises(self):
+        """自循环依赖 A→A 抛出 ValueError"""
+        plan = TeamPlan(
+            task="自循环任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=["a"]),
+            ],
+        )
+        with pytest.raises(ValueError, match="Circular dependency"):
+            plan.topological_sort()
+
+    def test_invalid_dependency_reference_raises(self):
+        """依赖不存在的阶段 ID 抛出 ValueError"""
+        plan = TeamPlan(
+            task="无效依赖任务",
+            phases=[
+                _make_phase(id="a", name="A", depends_on=["nonexistent"]),
+            ],
+        )
+        with pytest.raises(ValueError, match="non-existent phase"):
+            plan.topological_sort()
+
+
+class TestGetReadyPhases:
+    """get_ready_phases 就绪阶段测试"""
+
+    def test_initial_ready_phases(self):
+        """初始时只有无依赖的阶段就绪"""
+        plan = _make_pipeline_plan()
+        ready = plan.get_ready_phases()
+        assert len(ready) == 1
+        assert ready[0].id == "p1"
+
+    def test_ready_after_first_layer_completes(self):
+        """第一层完成后，第二层阶段就绪"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        ready = plan.get_ready_phases()
+        assert len(ready) == 2
+        assert {ph.id for ph in ready} == {"p2", "p3"}
+
+    def test_ready_after_partial_completion(self):
+        """部分完成：p1 完成后 p2 完成，p3 仍 pending → p4 不就绪"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p2", PhaseStatus.COMPLETED)
+        # p3 still pending, so p4 (depends on p2 AND p3) is not ready
+        ready = plan.get_ready_phases()
+        assert len(ready) == 1
+        assert ready[0].id == "p3"
+
+    def test_ready_excludes_running_phases(self):
+        """运行中的阶段不被视为就绪"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.RUNNING)
+        ready = plan.get_ready_phases()
+        assert len(ready) == 0
+
+    def test_ready_excludes_completed_phases(self):
+        """已完成的阶段不被视为就绪"""
+        plan = _make_pipeline_plan()
+        plan.update_phase_status("p1", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p2", PhaseStatus.COMPLETED)
+        plan.update_phase_status("p3", PhaseStatus.COMPLETED)
+        ready = plan.get_ready_phases()
+        assert len(ready) == 1
+        assert ready[0].id == "p4"
+
+
+class TestTeamPlanPhasesSerialization:
+    """TeamPlan phases 序列化测试"""
+
+    def test_to_dict_includes_phases(self):
+        """to_dict 包含 phases 字段"""
+        plan = _make_pipeline_plan()
+        d = plan.to_dict()
+        assert "phases" in d
+        assert len(d["phases"]) == 5
+        assert d["phases"][0]["id"] == "p1"
+        assert d["phases"][0]["depends_on"] == []
+
+    def test_from_dict_restores_phases(self):
+        """from_dict 恢复 phases"""
+        plan = _make_pipeline_plan()
+        d = plan.to_dict()
+        restored = TeamPlan.from_dict(d)
+
+        assert len(restored.phases) == len(plan.phases)
+        for original, restored_ph in zip(plan.phases, restored.phases):
+            assert restored_ph.id == original.id
+            assert restored_ph.name == original.name
+            assert restored_ph.assigned_expert == original.assigned_expert
+            assert restored_ph.task_description == original.task_description
+            assert restored_ph.depends_on == original.depends_on
+            assert restored_ph.status == original.status
+
+    def test_both_subtasks_and_phases_coexist(self):
+        """subtasks 和 phases 可以共存"""
+        plan = TeamPlan(
+            task="混合模式",
+            subtasks=[SubTask(id="s1", description="子任务1")],
+            phases=[_make_phase(id="p1", name="阶段1")],
+        )
+        d = plan.to_dict()
+        assert len(d["subtasks"]) == 1
+        assert len(d["phases"]) == 1
+        assert d["subtasks"][0]["id"] == "s1"
+        assert d["phases"][0]["id"] == "p1"