diff --git a/tests/unit/api/test_llm_route_coercion.py b/tests/unit/api/test_llm_route_coercion.py
index ccf0d2e..1c945fd 100644
--- a/tests/unit/api/test_llm_route_coercion.py
+++ b/tests/unit/api/test_llm_route_coercion.py
@@ -1,14 +1,18 @@
 # -*- coding: utf-8 -*-
-"""/llm 路由边界 ID 归一：user_id / config_id 字符串 → int，非法值 → 422。
+"""/llm 路由边界行为：user_id / config_id 归一（M2/M3）+ 缺配置 → 404。
 
-锁定 M2/M3 修复：弱类型 ID 不再下沉到 SQL 靠驱动隐式转换，路由层显式校验。
+锁定 M2/M3 修复：弱类型 ID 不再下沉到 SQL 靠驱动隐式转换，路由层显式校验；
+并验证统一解析未命中（含系统兜底）时翻成 HTTP 404，保持原有对外契约。
 """
 from __future__ import annotations
 
+from unittest.mock import AsyncMock
+
 import pytest
 from fastapi import HTTPException
 
-from src.api.routes.llm import _coerce_int
+from src.api.routes.llm import _coerce_int, _resolve_provider
+from src.core.llm.exceptions import UserModelConfigMissingError
 
 
 def test_coerce_int_valid():
@@ -27,3 +31,17 @@ def test_coerce_int_rejects_empty():
         _coerce_int("", "config_id")
     assert exc.value.status_code == 422
     assert "config_id" in exc.value.detail
+
+
+@pytest.mark.asyncio
+async def test_resolve_provider_missing_config_maps_to_404(monkeypatch):
+    """统一解析未命中（含系统兜底）抛 UserModelConfigMissingError → HTTP 404，
+    保持 /llm 端点原有对外行为。"""
+    async def _raise(**kwargs):
+        raise UserModelConfigMissingError("EMBEDDING", 123)
+
+    monkeypatch.setattr("src.api.routes.llm.aresolve_user_model", _raise)
+    with pytest.raises(HTTPException) as exc:
+        await _resolve_provider(db=AsyncMock(), user_id="123", capability="EMBEDDING")
+    assert exc.value.status_code == 404
+    assert "EMBEDDING" in exc.value.detail
diff --git a/tests/unit/api/test_recall_route.py b/tests/unit/api/test_recall_route.py
index 86555cb..ec9ca14 100644
--- a/tests/unit/api/test_recall_route.py
+++ b/tests/unit/api/test_recall_route.py
@@ -17,6 +17,7 @@
 from src.config import settings
 from src.core.pipeline.recall import (
     RecallError,
+    RecallFatalError,
     RecallHit,
     RecallResponse,
 )
@@ -295,6 +296,25 @@ def test_all_sources_failed_emits_sse_error(client):
         app.dependency_overrides.pop(get_recall_pipeline, None)
 
 
+def test_embedding_config_missing_emits_sse_error(client):
+    """发起用户无默认 EMBEDDING 配置 → pipeline 抛 RecallFatalError →
+    SSE error 事件返回 RECALL_EMBEDDING_CONFIG_MISSING（硬失败，不降级）。"""
+    fake = FakePipeline(exc=RecallFatalError("user embedding config missing"))
+    app.dependency_overrides[get_recall_pipeline] = lambda: fake
+    try:
+        resp = _post(TestClient(app), make_token(), {"query": "q", "user_id": 123, "dataset_ids": [1]})
+        assert resp.status_code == 200
+        assert resp.headers["content-type"].startswith("text/event-stream")
+        import json
+        name, data = _parse_sse(resp.text)[0]
+        assert name == "error"
+        payload = json.loads(data)
+        assert payload["code"] == "RECALL_EMBEDDING_CONFIG_MISSING"
+        assert "Traceback" not in payload["message"]
+    finally:
+        app.dependency_overrides.pop(get_recall_pipeline, None)
+
+
 def test_timeout_emits_sse_error(client, monkeypatch):
     monkeypatch.setattr(settings, "RECALL_STREAM_TIMEOUT_MS", 10)
     fake = FakePipeline(response=_ok_response(), delay=0.5)