diff --git a/tests/unit/service/test_customer_service_suitability.py b/tests/unit/service/test_customer_service_suitability.py
new file mode 100644
index 0000000..bac196f
--- /dev/null
+++ b/tests/unit/service/test_customer_service_suitability.py
@@ -0,0 +1,199 @@
+"""客服适当性出口的单元测试。
+
+这个出口会给出「能不能买」的结论，所以每条分支都必须锁住——写错一条就是误导客户。
+用例里的数字取自真实链路：南方季季盈90天是 R2，来自产品手册的「风险等级」行。
+"""
+
+from typing import Any, cast
+
+import pytest
+
+from app.core.contracts import AgentRequest, ConversationTurn, RequestContext
+from app.service.agent.implementations.customer_service import CustomerServiceAgent
+
+FALLBACK = "抱歉，这个问题我暂时无法给出准确答复。建议您拨打客服热线 400-XXX-XXXX 转人工客服咨询。"
+
+
+def _decision(**overrides: Any) -> dict[str, Any]:
+    base: dict[str, Any] = {
+        "allowed": True, "reason_code": "MATCHED", "required_disclosure": False,
+        "requires_confirmation": False, "requires_recording": False,
+        "customer_risk_level": 2, "assessment_valid_until": None,
+    }
+    base.update(overrides)
+    return base
+
+
+def _agent() -> CustomerServiceAgent:
+    """跳过 __init__ 造实例：本组用例只碰话术与 call_tool 替身。"""
+    return object.__new__(CustomerServiceAgent)
+
+
+def _request(*history: tuple[str, str]) -> AgentRequest:
+    turns = tuple(
+        ConversationTurn(role=cast(Any, role), content=content) for role, content in history
+    )
+    return AgentRequest(
+        agent_type="customer_service", session_id="s", message="c1客户能买它吗",
+        idempotency_key="1234567890123456", history=turns,
+    )
+
+
+def _hit(title: str, content: str) -> dict[str, Any]:
+    return {"doc_id": "PROD-007-03", "title": title, "content": content, "score": 0.9}
+
+
+# ---- 话术 ----
+
+def test_allowed_reply_names_product_level_and_customer_level() -> None:
+    text = CustomerServiceAgent._suitability_text("南方季季盈90天", 2, _decision())
+
+    assert "南方季季盈90天" in text
+    assert "R2（中低风险）" in text
+    assert "可以购买" in text
+    assert "C2" in text
+
+
+def test_disclosure_and_recording_are_disclosed_when_required() -> None:
+    text = CustomerServiceAgent._suitability_text(
+        "南方稳健增利180天", 4, _decision(required_disclosure=True, requires_recording=True)
+    )
+
+    assert "风险揭示书" in text
+    assert "双录" in text
+
+
+def test_rejection_does_not_assert_a_reason() -> None:
+    """拒绝的原因可能是等级不匹配、测评过期或未测评，不能一律说成"超出承受能力"。"""
+    text = CustomerServiceAgent._suitability_text(
+        "南方季季盈90天", 3, _decision(allowed=False)
+    )
+
+    assert "暂时无法购买" in text
+    assert "超出" not in text
+
+
+def test_missing_assessment_is_said_in_plain_words() -> None:
+    """档案里没有测评结果时不能写"您的等级为未记录"——客户看不懂。"""
+    text = CustomerServiceAgent._suitability_text(
+        "南方季季盈90天", 2, _decision(allowed=False, customer_risk_level=None)
+    )
+
+    assert "没有在有效期内的风险测评结果" in text
+    assert "未记录" not in text
+
+
+def test_validity_is_shortened_to_a_plain_date() -> None:
+    text = CustomerServiceAgent._suitability_text(
+        "南方季季盈90天", 2, _decision(assessment_valid_until="2027-01-15T00:00:00+00:00")
+    )
+
+    assert "2027-01-15" in text
+    assert "T00:00" not in text
+
+
+def test_unknown_level_falls_back_to_the_code() -> None:
+    text = CustomerServiceAgent._suitability_text("某产品", 9, _decision())
+
+    assert "R9" in text
+
+
+# ---- 产品名来源 ----
+
+def test_previous_topic_takes_the_subject_of_the_last_answer() -> None:
+    topic = CustomerServiceAgent._previous_topic(_request(
+        ("user", "季季盈90天起投多少"),
+        ("assistant", "南方季季盈90天：起投金额 1万元"),
+    ))
+
+    assert topic == "南方季季盈90天"
+
+
+def test_previous_topic_ignores_user_turns() -> None:
+    """客户的问句不是可信的产品名来源，只能从回答里取。"""
+    assert CustomerServiceAgent._previous_topic(
+        _request(("user", "季季盈90天起投多少"))
+    ) == ""
+
+
+def test_previous_topic_is_empty_after_a_fallback_answer() -> None:
+    """上一轮是兜底话术时取不出主语，调用方据此转人工（而不是瞎猜一个产品）。"""
+    assert CustomerServiceAgent._previous_topic(
+        _request(("user", "随便问点什么"), ("assistant", FALLBACK))
+    ) == ""
+
+
+# ---- 产品风险等级 ----
+
+async def _level(hits: list[dict[str, Any]]) -> int | None:
+    agent = _agent()
+
+    async def fake_call_tool(name: str, arguments: dict[str, Any], **kwargs: Any) -> Any:
+        return {"hits": hits, "degraded": False}
+
+    agent.call_tool = fake_call_tool  # type: ignore[method-assign]
+    return await agent._product_risk_level(
+        "南方季季盈90天", RequestContext(user_id="9001", trace_id="t")
+    )
+
+
+@pytest.mark.asyncio
+async def test_level_is_read_from_the_risk_level_row() -> None:
+    level = await _level([
+        _hit("手册 · 2.1 南方季季盈90天 · 风险等级", "南方季季盈90天：风险等级 R2（中低风险）")
+    ])
+
+    assert level == 2
+
+
+@pytest.mark.asyncio
+async def test_row_about_another_product_is_rejected() -> None:
+    """命中别的产品的等级行时必须放弃，否则会拿别人的等级去给客户做裁决。"""
+    level = await _level([
+        _hit("手册 · 3.1 南方稳健增利180天 · 风险等级", "南方稳健增利180天：风险等级 R3（中风险）")
+    ])
+
+    assert level is None
+
+
+@pytest.mark.asyncio
+async def test_enumeration_row_is_rejected() -> None:
+    """C1 的 FAQ 里写着"可购买 R1、R2"这种列举，那不是产品等级。"""
+    level = await _level([
+        _hit(
+            "C1 客户能买什么产品?",
+            "C1（保守型）客户可以购买 R1（低风险）、R2（中低风险）等级的产品。",
+        )
+    ])
+
+    assert level is None
+
+
+@pytest.mark.asyncio
+async def test_degraded_search_yields_no_level() -> None:
+    """检索降级时不能返回一个等级——那会让裁决建立在"其实没查到"之上。"""
+    agent = _agent()
+
+    async def fake_call_tool(name: str, arguments: dict[str, Any], **kwargs: Any) -> Any:
+        return {"hits": [], "degraded": True, "reason": "search_failed"}
+
+    agent.call_tool = fake_call_tool  # type: ignore[method-assign]
+
+    assert await agent._product_risk_level(
+        "南方季季盈90天", RequestContext(user_id="9001", trace_id="t")
+    ) is None
+
+
+@pytest.mark.asyncio
+async def test_tool_failure_yields_no_level() -> None:
+    """工具抛异常时返回 None（由调用方转人工），不能让异常冒到主链路。"""
+    agent = _agent()
+
+    async def fake_call_tool(name: str, arguments: dict[str, Any], **kwargs: Any) -> Any:
+        raise RuntimeError("milvus 挂了")
+
+    agent.call_tool = fake_call_tool  # type: ignore[method-assign]
+
+    assert await agent._product_risk_level(
+        "南方季季盈90天", RequestContext(user_id="9001", trace_id="t")
+    ) is None