233 lines
9.2 KiB
Python
233 lines
9.2 KiB
Python
"""对话接口（T-06 最小闭环 · FLOW §2）：四 Agent 统一 chat 入口。
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链路：X-Agent-Type 分流 + Agent 准入（deps.assert_agent_access，手册 §5.4）
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→ T-03 输入防护（input_guard：注入短语 / 超长，命中即拒 + input_guard_log
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留痕，fail-fast 在会话解析前）→ customer 归属固定本人 / 代理人等指定客户走
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G-01 归属校验（A-01 语义）→ SessionGuard（会话存在、actor/agent_type 一致
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AUTH_403_SESSION_AGENT、active 状态，手册 §9）→ memory_service 窗口 →
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agent_service（T-07 图 + T-04 Tool 节点：意图→归属校验→Core RO 只读查询）
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→ user/assistant 双消息落 MySQL + Redis 窗口 → 响应 {session_id, reply,
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has_disclaimer, trace_id}。
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落库：agent_session/agent_message（同 trace_id）；agent_tool_call 由 Tool
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节点落（T-04，success/blocked/error 全留痕）。审计：鉴权失败/越权经
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deps.deny 双写留痕；输入防护拒绝经 T-03 落 input_guard_log。
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"""
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from __future__ import annotations
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import logging
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from uuid import uuid4
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from fastapi import APIRouter, Depends, Request
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from pydantic import BaseModel, Field
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from app.api.deps import (
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AGENT_TYPES,
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AuthContext,
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assert_agent_access,
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assert_customer_access,
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deny,
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get_auth_context,
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)
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from app.repository.core_ro import CoreReadOnlyRepository
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from app.repository.risk_repository import RiskRepository
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from app.repository.session_repository import SessionRepository
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from app.service import agent_service, input_guard, memory_service
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from app.utils.exceptions import ApiError, StateConflict
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from app.utils.trace import current_trace, new_trace
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logger = logging.getLogger(__name__)
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router = APIRouter(prefix="/api/chat", tags=["chat"])
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# Pydantic 硬顶（仅防 DoS 的超宽上限）：业务上限 4000 由 input_guard
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# （T-03）判定——在 guard 层拦截才能落 input_guard_log 留痕；
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# Pydantic 层直接 422 会绕过留痕（F-03「拦截记录」要求）。
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MESSAGE_HARD_CEILING = 20000
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def _repo() -> RiskRepository:
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"""审计仓储（deny 留痕用；测试 monkeypatch 点）。"""
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return RiskRepository()
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def _session_repo() -> SessionRepository:
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"""会话仓储（测试 monkeypatch 点）。"""
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return SessionRepository()
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def _core_ro() -> CoreReadOnlyRepository:
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"""归属校验仓储（测试 monkeypatch 点）。"""
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return CoreReadOnlyRepository()
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class ChatRequest(BaseModel):
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session_id: str | None = Field(None, description="缺省新建会话；传入则续聊")
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message: str = Field(..., min_length=1, max_length=MESSAGE_HARD_CEILING)
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customer_id: str | None = Field(
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None, description="目标客户：customer 角色忽略（强制本人）；advisor/risk/analyst 可指定（过归属校验）"
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)
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title: str | None = Field(None, max_length=256)
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def _primary_role(auth: AuthContext) -> str:
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"""会话主角色（agent_session.actor_role）：按 Agent 边界优先序取（评审 P3-11，
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多角色 token 落库稳定）。"""
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for role in ("customer", "advisor", "analyst", "risk_officer", "compliance", "ops"):
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if role in auth.roles:
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return role
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return auth.roles[0] if auth.roles else "unknown"
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def _resolve_customer_id(
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auth: AuthContext, agent_type: str, requested: str | None
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) -> str | None:
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"""会话关联客户：customer 强制本人；其余角色指定时过 G-01 归属校验。"""
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if agent_type == "customer":
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if requested and requested != auth.customer_id:
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deny(auth, "AUTH_403_NOT_OWNER", _repo(), customer_id=requested, agent_type=agent_type)
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return auth.customer_id
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if requested:
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assert_customer_access(auth, requested, core_ro=_core_ro(), risk_repo=_repo())
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return requested
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return None
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@router.post("")
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def chat_api(req: ChatRequest, request: Request, auth: AuthContext = Depends(get_auth_context)) -> dict:
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agent_type = request.headers.get("X-Agent-Type", "").strip()
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if not agent_type:
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raise ApiError(401, "AUTH_401_MISSING_AGENT_TYPE", "missing X-Agent-Type header")
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if agent_type not in AGENT_TYPES:
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raise ApiError(400, "BAD_REQUEST", f"invalid X-Agent-Type: {agent_type}")
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assert_agent_access(auth, agent_type, risk_repo=_repo())
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message = req.message.strip()
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if not message:
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raise ApiError(400, "BAD_REQUEST", "message is blank")
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# T-03 限流（actor 级固定窗口，拍板 30 次/分）：先于内容防护——计数
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# 覆盖全部请求（含将被注入拦截的），重复攻击者快速收敛到 429，不再
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# 逐条扫描+留痕；Redis 异常 fail-open（可用性保护非安全边界）。
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if not input_guard.check_rate_limit(agent_type, auth.actor_id):
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try:
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_repo().insert_input_guard_log(
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trace_id=current_trace() or new_trace(),
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agent_type=agent_type,
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actor_id=auth.actor_id,
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guard_type=input_guard.GUARD_RATE_LIMIT,
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action="blocked",
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raw_excerpt=f"rate limited: {auth.actor_id}",
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session_id=req.session_id,
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)
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except Exception:
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logger.warning(
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"rate limit log failed (degraded): actor=%s", auth.actor_id, exc_info=True
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)
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raise ApiError(429, "GUARD_RATE_LIMITED", "rate limit exceeded, retry later")
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# T-03 输入防护（F-03/G-03）：准入后、会话解析前 fail-fast——被拒输入
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# 不建会话、不落消息表。命中即拒（拍板：宁可误拒不可漏放）；留痕失败
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# 降级 warning，拒绝语义优先（与 deps 401/403 留痕降级同口径）。
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verdict = input_guard.inspect_message(message)
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if verdict.blocked:
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try:
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_repo().insert_input_guard_log(
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trace_id=current_trace() or new_trace(),
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agent_type=agent_type,
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actor_id=auth.actor_id,
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guard_type=verdict.guard_type or input_guard.GUARD_INJECTION,
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action="blocked",
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raw_excerpt=message[:1024],
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session_id=(req.session_id or "")[:64], # P3 评审：未校验字段先截断再落审计库
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)
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except Exception:
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logger.warning(
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"input guard log failed (degraded): actor=%s type=%s",
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auth.actor_id,
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verdict.guard_type,
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exc_info=True,
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)
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code = (
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"GUARD_BLOCKED_OVERSIZE"
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if verdict.guard_type == input_guard.GUARD_OVERSIZE
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else "GUARD_BLOCKED_INJECTION"
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)
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raise ApiError(400, code, "message rejected by input guard")
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customer_id = _resolve_customer_id(auth, agent_type, req.customer_id)
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session_repo = _session_repo()
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if req.session_id:
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session = session_repo.get_session(req.session_id)
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if session is None:
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raise ApiError(404, "NOT_FOUND", f"session not found: {req.session_id}")
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# SessionGuard（手册 §9）：actor/agent_type 一致；他人会话 fail-closed
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if session["actor_id"] != auth.actor_id or session["agent_type"] != agent_type:
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deny(
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auth,
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"AUTH_403_SESSION_AGENT",
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_repo(),
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customer_id=session.get("customer_id"),
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message="session belongs to another actor or agent",
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agent_type=agent_type,
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)
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if session["status"] != "active":
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raise ApiError(409, "STATE_CONFLICT", f"session is {session['status']}")
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sid = session["session_id"]
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else:
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sid = f"sess-{uuid4().hex[:16]}"
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session_repo.create_session(
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session_id=sid,
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trace_id=current_trace(),
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agent_type=agent_type,
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actor_id=auth.actor_id,
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actor_role=_primary_role(auth),
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customer_id=customer_id,
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advisor_id=auth.actor_id if agent_type == "advisor" else None,
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title=req.title,
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)
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history = memory_service.get_recent(agent_type, sid)
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result = agent_service.chat(
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agent_type,
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history,
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message,
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session_id=sid,
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trace_id=current_trace(),
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actor={"actor_id": auth.actor_id, "roles": auth.roles, "token_type": auth.token_type},
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customer_id=customer_id,
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)
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# 落盘：user + assistant 同步写（异步化归后续）；同 trace_id 贯通
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trace_id = current_trace()
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seq = session_repo.next_seq_no(sid)
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session_repo.insert_message(
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session_id=sid, trace_id=trace_id, seq_no=seq, role="user", content=message
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)
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session_repo.insert_message(
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session_id=sid,
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trace_id=trace_id,
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seq_no=seq + 1,
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role="assistant",
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content=result["reply"],
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has_disclaimer=bool(result["has_disclaimer"]),
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)
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memory_service.append_window(
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agent_type,
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sid,
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[
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{"role": "user", "content": message},
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{"role": "assistant", "content": result["reply"]},
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],
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)
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return {
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"session_id": sid,
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"agent_type": agent_type,
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"customer_id": customer_id,
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"reply": result["reply"],
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"has_disclaimer": result["has_disclaimer"],
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"trace_id": trace_id,
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}
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