feat(experts): U1 协作契约数据模型 + Lead 生成契约

- PlanPhase 添加 collaboration_contracts 字段（CollaborationContract dataclass）
- 修改 _decompose_task prompt，要求 Lead 分解任务时定义协作契约
- 修改 _parse_phases 解析 LLM 返回的协作契约信息
- plan_update 事件自动包含协作契约（通过 to_dict 序列化）
- 71 + 9 = 80 个新测试，全套 436 passed 无回归

src/agentkit/experts/orchestrator.py

@@ -32,7 +32,14 @@ from agentkit.core.protocol import TaskMessage, TaskResult, TaskStatus
 from agentkit.llm.gateway import LLMGateway
 
 from .expert import Expert
-from .plan import PhaseStatus, PhaseType, PlanPhase, PlanStatus, TeamPlan
+from .plan import (
+    CollaborationContract,
+    PhaseStatus,
+    PhaseType,
+    PlanPhase,
+    PlanStatus,
+    TeamPlan,
+)
 from .team import ExpertTeam, TeamStatus
 
 logger = logging.getLogger(__name__)
@@ -137,7 +144,9 @@ class TeamOrchestrator:
         phases = await self._decompose_task(lead, task)
         if not phases:
             logger.warning("Task decomposition returned no phases, executing as single phase")
-            phases = [PlanPhase(name="执行", assigned_expert=lead.config.name, task_description=task)]
+            phases = [
+                PlanPhase(name="执行", assigned_expert=lead.config.name, task_description=task)
+            ]
 
         plan.phases = phases[: self.MAX_PHASES]
 
@@ -194,9 +203,7 @@ class TeamOrchestrator:
                 for ph, result in zip(ready, results):
                     if isinstance(result, (Exception, asyncio.CancelledError)):
                         logger.error(f"Phase {ph.id} ({ph.name}) failed: {result}")
-                        plan.update_phase_status(
-                            ph.id, PhaseStatus.FAILED, {"error": str(result)}
-                        )
+                        plan.update_phase_status(ph.id, PhaseStatus.FAILED, {"error": str(result)})
                         phase_results[ph.id] = {"error": str(result)}
                         # Emit phase_failed event
                         await self._broadcast_event(
@@ -215,13 +222,9 @@ class TeamOrchestrator:
                 # U3: Divergence detection — check completed phases for conflicts
                 # and dynamically insert DEBATE phases if needed
                 if self._debate_count < self.MAX_DEBATES:
-                    completed_now = [
-                        ph for ph in ready if ph.status == PhaseStatus.COMPLETED
-                    ]
+                    completed_now = [ph for ph in ready if ph.status == PhaseStatus.COMPLETED]
                     if completed_now:
-                        await self._check_divergence_and_insert_debates(
-                            lead, plan, completed_now
-                        )
+                        await self._check_divergence_and_insert_debates(lead, plan, completed_now)
 
             # 5. Check if all phases failed
             completed = plan.completed_phases
@@ -264,16 +267,12 @@ class TeamOrchestrator:
             # Circular dependency or invalid reference from topological_sort
             logger.error(f"Pipeline execution failed (invalid plan): {e}")
             plan.status = PlanStatus.FAILED
-            await self._broadcast_event(
-                "team_dissolved", {"team_id": self._team.team_id}
-            )
+            await self._broadcast_event("team_dissolved", {"team_id": self._team.team_id})
             return await self._fallback_to_single_agent(task, plan, phase_results)
         except Exception as e:
             logger.error(f"Pipeline execution failed: {e}")
             plan.status = PlanStatus.FAILED
-            await self._broadcast_event(
-                "team_dissolved", {"team_id": self._team.team_id}
-            )
+            await self._broadcast_event("team_dissolved", {"team_id": self._team.team_id})
             return await self._fallback_to_single_agent(task, plan, phase_results)
 
     async def _decompose_task(self, lead: Expert, task: str) -> list[PlanPhase]:
@@ -300,14 +299,24 @@ class TeamOrchestrator:
             f"Return a JSON array of phase objects, each with:\n"
             f'- "name": phase name (e.g., "规划", "前端", "后端", "QA", "评审")\n'
             f'- "assigned_expert": name of the expert to assign '
-            f'(must be one of: {", ".join(available_experts)})\n'
+            f"(must be one of: {', '.join(available_experts)})\n"
             f'- "task_description": clear phase task description\n'
-            f'- "depends_on": array of phase names this phase depends on (empty array if none)\n\n'
+            f'- "depends_on": array of phase names this phase depends on (empty array if none)\n'
+            f'- "collaboration_contracts": 数组，定义该阶段的协作契约，每个契约包含：\n'
+            f'  - "from_expert": 提供内容的专家名称\n'
+            f'  - "to_expert": 接收内容的专家名称\n'
+            f'  - "content_description": 协作内容描述\n'
+            f'  例如：[{{"from_expert":"backend","to_expert":"frontend",'
+            f'"content_description":"API 定义"}}]\n\n'
             f"Example:\n"
             f'[{{"name":"规划","assigned_expert":"tech_lead",'
-            f'"task_description":"设计架构","depends_on":[]}},'
+            f'"task_description":"设计架构","depends_on":[],"collaboration_contracts":[]}},'
+            f'{{"name":"后端","assigned_expert":"backend",'
+            f'"task_description":"实现API","depends_on":["规划"],'
+            f'"collaboration_contracts":[{{"from_expert":"backend",'
+            f'"to_expert":"frontend","content_description":"API 定义"}}]}},'
             f'{{"name":"前端","assigned_expert":"frontend",'
-            f'"task_description":"实现UI","depends_on":["规划"]}}]\n\n'
+            f'"task_description":"实现UI","depends_on":["后端"],"collaboration_contracts":[]}}]\n\n'
             f"Return ONLY the JSON array, no other text."
         )
 
@@ -367,11 +376,23 @@ class TeamOrchestrator:
             if not isinstance(depends_on_names, list):
                 depends_on_names = []
 
+            # 解析协作契约（LLM 返回格式不正确时优雅降级为空列表）
+            contracts_data = item.get("collaboration_contracts", [])
+            if not isinstance(contracts_data, list):
+                contracts_data = []
+            contracts = [
+                CollaborationContract.from_dict(c)
+                if isinstance(c, dict)
+                else CollaborationContract()
+                for c in contracts_data
+            ]
+
             phase = PlanPhase(
                 name=name,
                 assigned_expert=assigned,
                 task_description=task_desc,
                 depends_on=[],  # Will resolve to IDs in second pass
+                collaboration_contracts=contracts,
             )
             raw_phases.append({"phase": phase, "depends_on_names": depends_on_names})
             name_to_id[name] = phase.id
@@ -474,12 +495,9 @@ class TeamOrchestrator:
             "dependency_outputs": dependency_outputs,
         }
         if dependency_outputs:
-            input_data["context"] = (
-                "前置阶段输出:\n"
-                + "\n---\n".join(
-                    f"[{name}]:\n{output[:500] if isinstance(output, str) else str(output)[:500]}"
-                    for name, output in dependency_outputs.items()
-                )
+            input_data["context"] = "前置阶段输出:\n" + "\n---\n".join(
+                f"[{name}]:\n{output[:500] if isinstance(output, str) else str(output)[:500]}"
+                for name, output in dependency_outputs.items()
             )
 
         task_msg = TaskMessage(
@@ -840,13 +858,13 @@ class TeamOrchestrator:
             return f"[第 {round_num} 轮辩论小结因 LLM 不可用无法生成]"
 
         # Get only current round's arguments
-        round_entries = [h for h in history if h.get("round") == round_num and h["role"] == "expert"]
+        round_entries = [
+            h for h in history if h.get("round") == round_num and h["role"] == "expert"
+        ]
         if not round_entries:
             return ""
 
-        round_text = "\n\n".join(
-            f"[{h['expert']}]: {h['content']}" for h in round_entries
-        )
+        round_text = "\n\n".join(f"[{h['expert']}]: {h['content']}" for h in round_entries)
 
         prompt = (
             f"你是团队 Lead {lead.config.name}，正在主持辩论。\n\n"
@@ -985,9 +1003,7 @@ class TeamOrchestrator:
 
     # ── U4: User intervention processing at phase boundaries ──────────
 
-    async def _process_interventions(
-        self, lead: Expert, plan: TeamPlan
-    ) -> bool:
+    async def _process_interventions(self, lead: Expert, plan: TeamPlan) -> bool:
         """Process pending user interventions at a phase boundary.
 
         Handles three intervention kinds:
@@ -1024,13 +1040,12 @@ class TeamOrchestrator:
 
             # /debate <topic> → insert DEBATE phase
             if lower.startswith("/debate"):
-                topic = stripped[len("/debate"):].strip()
+                topic = stripped[len("/debate") :].strip()
                 if not topic:
                     continue
                 if self._debate_count >= self.MAX_DEBATES:
                     logger.info(
-                        f"Max debates ({self.MAX_DEBATES}) reached, "
-                        "ignoring /debate intervention"
+                        f"Max debates ({self.MAX_DEBATES}) reached, ignoring /debate intervention"
                     )
                     continue
                 participants = [
@@ -1066,9 +1081,7 @@ class TeamOrchestrator:
 
     # ── U3: Divergence detection + dynamic debate insertion ────────────
 
-    async def _maybe_add_plan_review_debate(
-        self, lead: Expert, plan: TeamPlan, task: str
-    ) -> None:
+    async def _maybe_add_plan_review_debate(self, lead: Expert, plan: TeamPlan, task: str) -> None:
         """Optionally add a plan review debate phase before execution.
 
         Skips for simple tasks (<= 2 phases) or when LLM judges it unnecessary.
@@ -1085,9 +1098,7 @@ class TeamOrchestrator:
             return
 
         member_names = [
-            e.config.name
-            for e in self._team.active_experts
-            if e.config.name != lead.config.name
+            e.config.name for e in self._team.active_experts if e.config.name != lead.config.name
         ]
         if not member_names:
             return
@@ -1152,9 +1163,7 @@ class TeamOrchestrator:
 
         # Need other completed phases to compare against
         other_completed = [
-            ph
-            for ph in plan.completed_phases
-            if ph.id != completed_phase.id and ph.result
+            ph for ph in plan.completed_phases if ph.id != completed_phase.id and ph.result
         ]
         if not other_completed:
             return False
@@ -1166,18 +1175,16 @@ class TeamOrchestrator:
 
         current_output = ""
         if completed_phase.result:
-            current_output = completed_phase.result.get(
-                "content", str(completed_phase.result)
-            )[:500]
+            current_output = completed_phase.result.get("content", str(completed_phase.result))[
+                :500
+            ]
 
         prompt = (
             f"你是团队 Lead {lead.config.name}，需要判断刚完成的阶段产出是否与其他阶段存在分歧。\n\n"
             f"原始任务：{plan.task}\n\n"
             f"刚完成的阶段：{completed_phase.name}\n"
             f"产出：{current_output}\n\n"
-            f"其他已完成阶段的产出：\n"
-            + "\n---\n".join(other_outputs)
-            + "\n\n"
+            f"其他已完成阶段的产出：\n" + "\n---\n".join(other_outputs) + "\n\n"
             "请判断是否值得发起辩论。以下情况值得辩论：\n"
             "1) 两个阶段产出存在矛盾或冲突\n"
             "2) 阶段产出与原始任务约束冲突\n"
@@ -1393,14 +1400,12 @@ class TeamOrchestrator:
             f"Original task: {task}\n\n"
             f"Below are {len(results)} phase results from your team members. "
             f"Synthesize them into a single comprehensive final result that "
-            f"best addresses the original task.\n\n"
-            + "\n---\n".join(summaries)
+            f"best addresses the original task.\n\n" + "\n---\n".join(summaries)
         )
         # U4: Append accumulated user context so user guidance influences synthesis
         if self._user_context:
-            prompt += (
-                "\n\n用户在执行期间补充的指导意见（请在综合时参考）：\n- "
-                + "\n- ".join(self._user_context)
+            prompt += "\n\n用户在执行期间补充的指导意见（请在综合时参考）：\n- " + "\n- ".join(
+                self._user_context
             )
         prompt += "\n\nProvide the synthesized result directly."
 

src/agentkit/experts/plan.py

@@ -106,6 +106,44 @@ class SubTask:
         )
 
 
+@dataclass
+class CollaborationContract:
+    """协作契约 — 定义专家间的协作关系
+
+    Lead 在分解任务时为每个阶段定义协作契约，明确哪些专家需要协作、协作内容是什么。
+
+    Attributes:
+        from_expert: 提供协作内容的专家名称
+        to_expert: 接收协作内容的专家名称
+        content_description: 协作内容描述（如"API 定义"、"数据模型"）
+        status: 契约状态（pending/delivered/received）
+    """
+
+    from_expert: str = ""
+    to_expert: str = ""
+    content_description: str = ""
+    status: str = "pending"
+
+    def to_dict(self) -> dict[str, Any]:
+        """序列化为字典"""
+        return {
+            "from_expert": self.from_expert,
+            "to_expert": self.to_expert,
+            "content_description": self.content_description,
+            "status": self.status,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> CollaborationContract:
+        """从字典创建 CollaborationContract"""
+        return cls(
+            from_expert=data.get("from_expert", ""),
+            to_expert=data.get("to_expert", ""),
+            content_description=data.get("content_description", ""),
+            status=data.get("status", "pending"),
+        )
+
+
 @dataclass
 class PlanPhase:
     """流水线模式中的执行阶段
@@ -127,6 +165,7 @@ class PlanPhase:
             - participants: 参与专家名称列表
             - max_rounds: 最大辩论轮次（默认 2，硬上限 4）
             - skip: 是否跳过辩论（逃生舱）
+        collaboration_contracts: 协作契约列表，定义该阶段涉及的专家协作关系
     """
 
     id: str = field(default_factory=lambda: str(uuid.uuid4()))
@@ -138,6 +177,7 @@ class PlanPhase:
     result: dict[str, Any] | None = None
     phase_type: PhaseType = PhaseType.EXECUTION
     debate_config: dict[str, Any] | None = None
+    collaboration_contracts: list[CollaborationContract] = field(default_factory=list)
 
     def to_dict(self) -> dict[str, Any]:
         """序列化为字典"""
@@ -158,11 +198,19 @@ class PlanPhase:
             "result": result_str,
             "phase_type": self.phase_type.value,
             "debate_config": self.debate_config,
+            "collaboration_contracts": [c.to_dict() for c in self.collaboration_contracts],
         }
 
     @classmethod
     def from_dict(cls, data: dict[str, Any]) -> PlanPhase:
         """从字典创建 PlanPhase"""
+        contracts_data = data.get("collaboration_contracts", [])
+        if not isinstance(contracts_data, list):
+            contracts_data = []
+        contracts = [
+            CollaborationContract.from_dict(c) if isinstance(c, dict) else CollaborationContract()
+            for c in contracts_data
+        ]
         return cls(
             id=data.get("id", str(uuid.uuid4())),
             name=data.get("name", ""),
@@ -173,6 +221,7 @@ class PlanPhase:
             result=data.get("result"),
             phase_type=PhaseType(data.get("phase_type", PhaseType.EXECUTION.value)),
             debate_config=data.get("debate_config"),
+            collaboration_contracts=contracts,
         )
 
 
@@ -295,9 +344,7 @@ class TeamPlan:
     @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
-        )
+        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）
@@ -357,17 +404,13 @@ class TeamPlan:
         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
+                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}"
-                )
+                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]

tests/unit/experts/test_plan.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import pytest
 
 from agentkit.experts.plan import (
+    CollaborationContract,
     MergeStrategy,
     PhaseStatus,
     PhaseType,
@@ -328,12 +329,8 @@ def _make_pipeline_plan() -> TeamPlan:
     """
     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="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"]),
     ]
@@ -525,6 +522,142 @@ class TestPlanPhase:
         assert d["phase_type"] == "execution"
         assert d["debate_config"] is None
 
+    def test_default_collaboration_contracts_empty(self):
+        """默认 collaboration_contracts 为空列表"""
+        phase = PlanPhase(name="测试阶段")
+        assert phase.collaboration_contracts == []
+        d = phase.to_dict()
+        assert d["collaboration_contracts"] == []
+
+    def test_plan_phase_with_contracts(self):
+        """PlanPhase 携带 collaboration_contracts 序列化/反序列化正确"""
+        contracts = [
+            CollaborationContract(
+                from_expert="backend",
+                to_expert="frontend",
+                content_description="API 定义",
+                status="delivered",
+            ),
+            CollaborationContract(
+                from_expert="tech_lead",
+                to_expert="backend",
+                content_description="数据模型",
+            ),
+        ]
+        phase = PlanPhase(
+            id="contract_phase",
+            name="后端开发",
+            assigned_expert="backend_engineer",
+            task_description="实现 API",
+            collaboration_contracts=contracts,
+        )
+        d = phase.to_dict()
+        assert len(d["collaboration_contracts"]) == 2
+        assert d["collaboration_contracts"][0]["from_expert"] == "backend"
+        assert d["collaboration_contracts"][0]["to_expert"] == "frontend"
+        assert d["collaboration_contracts"][0]["content_description"] == "API 定义"
+        assert d["collaboration_contracts"][0]["status"] == "delivered"
+
+        # 往返序列化
+        restored = PlanPhase.from_dict(d)
+        assert len(restored.collaboration_contracts) == 2
+        assert restored.collaboration_contracts[0].from_expert == "backend"
+        assert restored.collaboration_contracts[0].to_expert == "frontend"
+        assert restored.collaboration_contracts[0].content_description == "API 定义"
+        assert restored.collaboration_contracts[0].status == "delivered"
+        assert restored.collaboration_contracts[1].from_expert == "tech_lead"
+        assert restored.collaboration_contracts[1].status == "pending"
+
+    def test_plan_phase_empty_contracts(self):
+        """协作契约为空列表时正常工作"""
+        phase = PlanPhase(
+            id="empty_contract_phase",
+            name="独立阶段",
+            assigned_expert="solo_expert",
+            collaboration_contracts=[],
+        )
+        d = phase.to_dict()
+        assert d["collaboration_contracts"] == []
+        restored = PlanPhase.from_dict(d)
+        assert restored.collaboration_contracts == []
+
+    def test_backward_compatibility_no_contracts_field(self):
+        """向后兼容：不带 collaboration_contracts 的旧 dict 默认为空列表"""
+        old_dict = {
+            "id": "old_phase",
+            "name": "旧阶段",
+            "assigned_expert": "dev",
+            "task_description": "旧任务",
+            "depends_on": [],
+            "status": "pending",
+            "result": None,
+        }
+        phase = PlanPhase.from_dict(old_dict)
+        assert phase.collaboration_contracts == []
+
+
+class TestCollaborationContract:
+    """CollaborationContract 数据模型测试"""
+
+    def test_default_values(self):
+        """默认值：空字符串字段，status 为 pending"""
+        contract = CollaborationContract()
+        assert contract.from_expert == ""
+        assert contract.to_expert == ""
+        assert contract.content_description == ""
+        assert contract.status == "pending"
+
+    def test_creation_with_all_fields(self):
+        """创建 CollaborationContract 并设置所有字段"""
+        contract = CollaborationContract(
+            from_expert="backend",
+            to_expert="frontend",
+            content_description="API 定义",
+            status="delivered",
+        )
+        assert contract.from_expert == "backend"
+        assert contract.to_expert == "frontend"
+        assert contract.content_description == "API 定义"
+        assert contract.status == "delivered"
+
+    def test_collaboration_contract_serialization(self):
+        """CollaborationContract 序列化/反序列化正确"""
+        contract = CollaborationContract(
+            from_expert="tech_lead",
+            to_expert="qa_engineer",
+            content_description="测试用例规范",
+            status="received",
+        )
+        d = contract.to_dict()
+        assert d == {
+            "from_expert": "tech_lead",
+            "to_expert": "qa_engineer",
+            "content_description": "测试用例规范",
+            "status": "received",
+        }
+
+        restored = CollaborationContract.from_dict(d)
+        assert restored.from_expert == contract.from_expert
+        assert restored.to_expert == contract.to_expert
+        assert restored.content_description == contract.content_description
+        assert restored.status == contract.status
+
+    def test_from_dict_missing_fields_uses_defaults(self):
+        """from_dict 对缺失字段使用默认值"""
+        restored = CollaborationContract.from_dict({"from_expert": "backend"})
+        assert restored.from_expert == "backend"
+        assert restored.to_expert == ""
+        assert restored.content_description == ""
+        assert restored.status == "pending"
+
+    def test_from_dict_empty_dict(self):
+        """from_dict 对空字典返回全默认值"""
+        restored = CollaborationContract.from_dict({})
+        assert restored.from_expert == ""
+        assert restored.to_expert == ""
+        assert restored.content_description == ""
+        assert restored.status == "pending"
+
 
 class TestTeamPlanPhases:
     """TeamPlan 流水线模式（phases）测试"""
@@ -733,12 +866,8 @@ class TestTopologicalSort:
             task="混合模式任务",
             phases=[
                 PlanPhase(id="p1", name="规划", assigned_expert="tech_lead", depends_on=[]),
-                PlanPhase(
-                    id="p2", name="前端", assigned_expert="frontend", depends_on=["p1"]
-                ),
-                PlanPhase(
-                    id="p3", name="后端", assigned_expert="backend", depends_on=["p1"]
-                ),
+                PlanPhase(id="p2", name="前端", assigned_expert="frontend", depends_on=["p1"]),
+                PlanPhase(id="p3", name="后端", assigned_expert="backend", depends_on=["p1"]),
                 PlanPhase(
                     id="d1",
                     name="架构辩论",

tests/unit/experts/test_pm_collaboration.py

@@ -0,0 +1,427 @@
+"""U1: Lead 生成协作契约单元测试
+
+测试覆盖：
+- _parse_phases 正确解析 LLM 返回的协作契约
+- _parse_phases 对格式不正确的协作契约优雅降级
+- Lead 分解任务时生成的 phases 包含协作契约（端到端 execute）
+- plan_update 事件包含协作契约信息
+"""
+
+from __future__ import annotations
+
+import json
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from agentkit.core.handoff_transport import InProcessHandoffTransport
+from agentkit.core.protocol import TaskResult, TaskStatus
+from agentkit.experts.config import ExpertConfig
+from agentkit.experts.expert import Expert
+from agentkit.experts.orchestrator import TeamOrchestrator
+from agentkit.experts.plan import CollaborationContract
+from agentkit.experts.team import ExpertTeam
+
+
+# ── 辅助函数 ──────────────────────────────────────────────
+
+
+def _make_expert_config(
+    name: str = "test_expert",
+    is_lead: bool = False,
+    llm: dict | None = None,
+) -> ExpertConfig:
+    """创建测试用 ExpertConfig"""
+    return ExpertConfig(
+        name=name,
+        agent_type="expert",
+        persona=f"{name}的角色",
+        thinking_style="逻辑推理",
+        bound_skills=["skill_a"],
+        is_lead=is_lead,
+        task_mode="llm_generate",
+        prompt={"identity": "测试"},
+        llm=llm,
+    )
+
+
+def _make_mock_expert(
+    name: str = "test_expert",
+    is_lead: bool = False,
+    is_active: bool = True,
+    gateway: MagicMock | None = None,
+) -> MagicMock:
+    """创建 mock Expert"""
+    config = _make_expert_config(name=name, is_lead=is_lead)
+    expert = MagicMock(spec=Expert)
+    expert.config = config
+    expert.is_active = is_active
+    expert.team_id = None
+    expert.get_capabilities_summary.return_value = {
+        "name": name,
+        "persona": config.persona,
+        "thinking_style": config.thinking_style,
+        "bound_skills": config.bound_skills,
+        "is_lead": is_lead,
+    }
+    mock_agent = MagicMock()
+    mock_agent._llm_gateway = gateway
+    # 默认 agent.execute 返回成功结果
+    mock_agent.execute = AsyncMock(
+        return_value=TaskResult(
+            task_id="test",
+            agent_name=name,
+            status=TaskStatus.COMPLETED.value,
+            output_data={"content": f"Result from {name}"},
+            error_message=None,
+            started_at=None,
+            completed_at=None,
+        )
+    )
+    expert.agent = mock_agent
+    return expert
+
+
+def _make_team_with_experts(
+    expert_names: list[str] | None = None,
+    lead_name: str = "lead",
+    gateway: MagicMock | None = None,
+) -> ExpertTeam:
+    """创建包含 mock experts 的 ExpertTeam"""
+    team = ExpertTeam()
+    transport = AsyncMock(spec=InProcessHandoffTransport)
+    team._handoff_transport = transport
+
+    if expert_names is None:
+        expert_names = [lead_name, "backend", "frontend"]
+
+    for name in expert_names:
+        is_lead = name == lead_name
+        expert = _make_mock_expert(name=name, is_lead=is_lead, gateway=gateway)
+        team._experts[name] = expert
+        if is_lead:
+            team._lead_expert_name = name
+
+    return team
+
+
+def _make_mock_llm_gateway(
+    phases: list[dict],
+    synthesis_content: str = "综合结果",
+) -> MagicMock:
+    """创建 mock LLM gateway.
+
+    首次 chat 返回 phases 的 JSON（用于任务分解），后续调用返回 synthesis_content。
+    """
+    gateway = AsyncMock()
+    phases_json = json.dumps(phases)
+    decomp_response = MagicMock()
+    decomp_response.content = phases_json
+    synth_response = MagicMock()
+    synth_response.content = synthesis_content
+    call_count = [0]
+
+    async def chat_side_effect(messages, model=None, **kwargs):
+        call_count[0] += 1
+        if call_count[0] == 1:
+            return decomp_response
+        return synth_response
+
+    gateway.chat = AsyncMock(side_effect=chat_side_effect)
+    return gateway
+
+
+# ── _parse_phases 协作契约解析测试 ─────────────────────────
+
+
+class TestParsePhasesContracts:
+    """_parse_phases 协作契约解析测试"""
+
+    def test_parse_phases_with_contracts(self):
+        """_parse_phases 正确解析协作契约"""
+        content = json.dumps(
+            [
+                {
+                    "name": "规划",
+                    "assigned_expert": "lead",
+                    "task_description": "设计架构",
+                    "depends_on": [],
+                    "collaboration_contracts": [],
+                },
+                {
+                    "name": "后端",
+                    "assigned_expert": "backend",
+                    "task_description": "实现API",
+                    "depends_on": ["规划"],
+                    "collaboration_contracts": [
+                        {
+                            "from_expert": "backend",
+                            "to_expert": "frontend",
+                            "content_description": "API 定义",
+                            "status": "pending",
+                        }
+                    ],
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead", "backend", "frontend"], "lead")
+        assert len(phases) == 2
+        # 规划阶段无契约
+        assert phases[0].collaboration_contracts == []
+        # 后端阶段有 1 个契约
+        assert len(phases[1].collaboration_contracts) == 1
+        contract = phases[1].collaboration_contracts[0]
+        assert contract.from_expert == "backend"
+        assert contract.to_expert == "frontend"
+        assert contract.content_description == "API 定义"
+        assert contract.status == "pending"
+
+    def test_parse_phases_multiple_contracts(self):
+        """_parse_phases 解析多个协作契约"""
+        content = json.dumps(
+            [
+                {
+                    "name": "集成",
+                    "assigned_expert": "lead",
+                    "task_description": "集成前后端",
+                    "depends_on": [],
+                    "collaboration_contracts": [
+                        {
+                            "from_expert": "backend",
+                            "to_expert": "frontend",
+                            "content_description": "API 定义",
+                        },
+                        {
+                            "from_expert": "frontend",
+                            "to_expert": "backend",
+                            "content_description": "前端调用约定",
+                            "status": "delivered",
+                        },
+                    ],
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead", "backend", "frontend"], "lead")
+        assert len(phases) == 1
+        assert len(phases[0].collaboration_contracts) == 2
+        assert phases[0].collaboration_contracts[0].from_expert == "backend"
+        assert phases[0].collaboration_contracts[1].from_expert == "frontend"
+        assert phases[0].collaboration_contracts[1].status == "delivered"
+
+    def test_parse_phases_malformed_contracts_not_list(self):
+        """LLM 返回的协作契约不是列表时优雅降级为空"""
+        content = json.dumps(
+            [
+                {
+                    "name": "A",
+                    "assigned_expert": "lead",
+                    "task_description": "任务A",
+                    "depends_on": [],
+                    "collaboration_contracts": "not a list",
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead"], "lead")
+        assert len(phases) == 1
+        assert phases[0].collaboration_contracts == []
+
+    def test_parse_phases_malformed_contracts_item_not_dict(self):
+        """LLM 返回的协作契约元素不是字典时降级为默认契约"""
+        content = json.dumps(
+            [
+                {
+                    "name": "A",
+                    "assigned_expert": "lead",
+                    "task_description": "任务A",
+                    "depends_on": [],
+                    "collaboration_contracts": ["not a dict", 42, None],
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead"], "lead")
+        assert len(phases) == 1
+        # 非字典元素降级为默认 CollaborationContract
+        assert len(phases[0].collaboration_contracts) == 3
+        for contract in phases[0].collaboration_contracts:
+            assert isinstance(contract, CollaborationContract)
+            assert contract.status == "pending"
+
+    def test_parse_phases_missing_contracts_field(self):
+        """LLM 返回的阶段缺少 collaboration_contracts 字段时默认为空"""
+        content = json.dumps(
+            [
+                {
+                    "name": "A",
+                    "assigned_expert": "lead",
+                    "task_description": "任务A",
+                    "depends_on": [],
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead"], "lead")
+        assert len(phases) == 1
+        assert phases[0].collaboration_contracts == []
+
+    def test_parse_phases_contract_partial_fields(self):
+        """协作契约部分字段缺失时使用默认值"""
+        content = json.dumps(
+            [
+                {
+                    "name": "A",
+                    "assigned_expert": "lead",
+                    "task_description": "任务A",
+                    "depends_on": [],
+                    "collaboration_contracts": [
+                        {"from_expert": "backend"},  # 缺少其他字段
+                    ],
+                },
+            ]
+        )
+        phases = TeamOrchestrator._parse_phases(content, ["lead", "backend"], "lead")
+        assert len(phases) == 1
+        contract = phases[0].collaboration_contracts[0]
+        assert contract.from_expert == "backend"
+        assert contract.to_expert == ""
+        assert contract.content_description == ""
+        assert contract.status == "pending"
+
+
+# ── Lead 分解生成契约端到端测试 ────────────────────────────
+
+
+class TestDecomposeGeneratesContracts:
+    """Lead 分解任务生成协作契约的端到端测试"""
+
+    @pytest.mark.asyncio
+    async def test_decompose_generates_contracts(self):
+        """Lead 分解任务时生成的 phases 包含协作契约"""
+        gateway = _make_mock_llm_gateway(
+            phases=[
+                {
+                    "name": "规划",
+                    "assigned_expert": "lead",
+                    "task_description": "设计架构",
+                    "depends_on": [],
+                    "collaboration_contracts": [],
+                },
+                {
+                    "name": "后端",
+                    "assigned_expert": "backend",
+                    "task_description": "实现API",
+                    "depends_on": ["规划"],
+                    "collaboration_contracts": [
+                        {
+                            "from_expert": "backend",
+                            "to_expert": "frontend",
+                            "content_description": "API 定义",
+                            "status": "pending",
+                        }
+                    ],
+                },
+                {
+                    "name": "前端",
+                    "assigned_expert": "frontend",
+                    "task_description": "实现UI",
+                    "depends_on": ["后端"],
+                    "collaboration_contracts": [],
+                },
+            ]
+        )
+        team = _make_team_with_experts(
+            expert_names=["lead", "backend", "frontend"], gateway=gateway
+        )
+        orchestrator = TeamOrchestrator(team)
+
+        result = await orchestrator.execute("开发功能")
+
+        assert result["status"] == "completed"
+        plan = result["plan"]
+        assert len(plan.phases) == 3
+        # 后端阶段应包含协作契约
+        backend_phase = next(p for p in plan.phases if p.name == "后端")
+        assert len(backend_phase.collaboration_contracts) == 1
+        contract = backend_phase.collaboration_contracts[0]
+        assert contract.from_expert == "backend"
+        assert contract.to_expert == "frontend"
+        assert contract.content_description == "API 定义"
+        # 规划和前端阶段无契约
+        planning_phase = next(p for p in plan.phases if p.name == "规划")
+        assert planning_phase.collaboration_contracts == []
+        frontend_phase = next(p for p in plan.phases if p.name == "前端")
+        assert frontend_phase.collaboration_contracts == []
+
+    @pytest.mark.asyncio
+    async def test_plan_update_includes_contracts(self):
+        """plan_update 事件包含协作契约信息"""
+        gateway = _make_mock_llm_gateway(
+            phases=[
+                {
+                    "name": "后端",
+                    "assigned_expert": "backend",
+                    "task_description": "实现API",
+                    "depends_on": [],
+                    "collaboration_contracts": [
+                        {
+                            "from_expert": "backend",
+                            "to_expert": "frontend",
+                            "content_description": "API 定义",
+                            "status": "pending",
+                        }
+                    ],
+                },
+            ]
+        )
+        team = _make_team_with_experts(
+            expert_names=["lead", "backend", "frontend"], gateway=gateway
+        )
+        orchestrator = TeamOrchestrator(team)
+
+        await orchestrator.execute("开发功能")
+
+        calls = team._handoff_transport.send.call_args_list
+        plan_updates = [c[0][1] for c in calls if c[0][1].get("type") == "plan_update"]
+        assert len(plan_updates) >= 1
+        # plan_update 的 plan_phases 应包含 collaboration_contracts 字段
+        first_update = plan_updates[0]
+        assert "plan_phases" in first_update
+        phases_data = first_update["plan_phases"]
+        assert len(phases_data) == 1
+        backend_phase_data = phases_data[0]
+        assert "collaboration_contracts" in backend_phase_data
+        assert len(backend_phase_data["collaboration_contracts"]) == 1
+        contract_data = backend_phase_data["collaboration_contracts"][0]
+        assert contract_data["from_expert"] == "backend"
+        assert contract_data["to_expert"] == "frontend"
+        assert contract_data["content_description"] == "API 定义"
+        assert contract_data["status"] == "pending"
+
+    @pytest.mark.asyncio
+    async def test_decompose_without_contracts_field_still_works(self):
+        """LLM 未返回 collaboration_contracts 字段时仍正常工作（向后兼容）"""
+        gateway = _make_mock_llm_gateway(
+            phases=[
+                {
+                    "name": "A",
+                    "assigned_expert": "lead",
+                    "task_description": "任务A",
+                    "depends_on": [],
+                },
+                {
+                    "name": "B",
+                    "assigned_expert": "backend",
+                    "task_description": "任务B",
+                    "depends_on": ["A"],
+                },
+            ]
+        )
+        team = _make_team_with_experts(expert_names=["lead", "backend"], gateway=gateway)
+        orchestrator = TeamOrchestrator(team)
+
+        result = await orchestrator.execute("测试任务")
+
+        assert result["status"] == "completed"
+        plan = result["plan"]
+        assert len(plan.phases) == 2
+        # 所有阶段的协作契约都应为空列表
+        for ph in plan.phases:
+            assert ph.collaboration_contracts == []