feat：完成重构和测试

app/services/agent.py

@@ -10,19 +10,13 @@ from loguru import logger
 from app.config import settings
 from app.core.exceptions import BizException
 from app.observability.tracing import astream_screen
+from app.processor.history import trim_history
 from app.schemas.agent import AgentResult, ResumeRequest
 from app.schemas.conversation import Turn
 from app.schemas.request import DesignRequest
 from app.services.conversation import ConversationStore
 
 
-SUMMARY_MAX_CHARS = 500
-
-
-def _clip(text: str) -> str:
-    return text if len(text) <= SUMMARY_MAX_CHARS else text[:SUMMARY_MAX_CHARS] + "…"
-
-
 class AgentService:
     def __init__(self, graph, store: ConversationStore):
         self.graph = graph
@@ -51,11 +45,18 @@ class AgentService:
             raise
 
         payload = request.model_dump(mode="json")
-        # 历史只信任服务端记录，覆盖前端可能携带的同名扩展字段
-        payload["history"] = [
-            {"user": turn.prompt, "assistant": turn.summary, "outcome": turn.outcome}
-            for turn in turns
-        ]
+        # 历史只信任服务端记录，覆盖前端可能携带的同名扩展字段；记录是完整的，这里按 token 预算裁剪
+        payload["history"] = trim_history(
+            [
+                {
+                    "user": turn.prompt,
+                    "assistant": turn.summary,
+                    "outcome": turn.outcome,
+                }
+                for turn in turns
+            ],
+            settings.history_max_tokens,
+        )
 
         return (
             thread_id,
@@ -144,17 +145,17 @@ class AgentService:
         self._conversation_of[thread_id] = conversation_id
 
     @staticmethod
-    def _summarize(state, result: AgentResult) -> str:
-        """用一句话描述本轮结果，只陈述后端生成了什么，不代表前端已执行"""
+    def _summarize(result: AgentResult) -> str:
+        """本轮助手一侧的完整文本，只陈述后端生成了什么，不代表前端已执行；不截断，带入请求时再按预算裁剪"""
         if result.status == "waiting_for_input":
             question = result.clarification.question if result.clarification else ""
-            return _clip(f"向用户提问：{question}")
+            return f"向用户提问：{question}"
         if result.status == "cancelled":
             return "用户取消了本次补充"
         if result.status == "failed":
-            return _clip(f"处理失败：{result.answer or '未知原因'}")
+            return f"处理失败：{result.answer or '未知原因'}"
         if result.answer:
-            return _clip(result.answer)
+            return result.answer
         return f"已生成 {len(result.actions)} 个画布动作"
 
     async def _save_turn(self, state, result: AgentResult) -> None:
@@ -167,7 +168,7 @@ class AgentService:
                     message_id=result.message_id,
                     prompt=state["request"]["prompt"],
                     outcome=result.status,
-                    summary=self._summarize(state, result),
+                    summary=self._summarize(result),
                     created_at=datetime.now(timezone.utc),
                 )
             )