diff --git a/app/models/comparison.py b/app/models/comparison.py
index c351e94..a0e9165 100644
--- a/app/models/comparison.py
+++ b/app/models/comparison.py
@@ -83,7 +83,7 @@ class ComparisonRecord(Base):
     # ===== 明细(JSON,越详细越好)=====
     # 下单菜品 [{name, qty, specs?}]
     items: Mapped[list] = mapped_column(_JSON, nullable=False, default=list)
-    # 逐平台对比 [{platform_id, platform_name, package, price, is_source, rank, coupon_saved}](price/coupon_saved 单位:元,原样存)
+    # 逐平台对比 [{platform_id, platform_name, package, price, is_source, rank, coupon_saved, coupon_name}](price/coupon_saved 单位:元,原样存;coupon_name=优惠来源名)
     comparison_results: Mapped[list] = mapped_column(_JSON, nullable=False, default=list)
     # 目标平台未找到、跳过的菜名
     skipped_dish_names: Mapped[list] = mapped_column(_JSON, nullable=False, default=list)
diff --git a/app/schemas/compare_record.py b/app/schemas/compare_record.py
index d431d46..b2bb4d0 100644
--- a/app/schemas/compare_record.py
+++ b/app/schemas/compare_record.py
@@ -37,6 +37,9 @@ class ComparisonResultIn(BaseModel):
     # 必须显式声明: 落库走 model_dump(), pydantic 默认丢未知字段, 不声明这行会被悄悄吞掉。
     # 各平台抠到红包即带值(2026-06 起源平台 Phase1 意图识别也抠, 当前仅淘宝源)。见 pricebot 侧 比价红包额留痕-实现方案.md。
     coupon_saved: float | None = None
+    # 优惠**来源名**(展示用, best-effort): 美团"外卖大额神券"/京东"百亿补贴"/淘宝"平台红包"。
+    # None=没抠到 → 前端走通用"红包"。同样必须显式声明否则上报边界被 pydantic 静默丢弃(pricebot#38 引入)。
+    coupon_name: str | None = None
 
 
 class ComparisonRecordIn(BaseModel):
diff --git a/docs/api/compare-record-report.md b/docs/api/compare-record-report.md
index 9f6dde0..162cf2b 100644
--- a/docs/api/compare-record-report.md
+++ b/docs/api/compare-record-report.md
@@ -31,9 +31,10 @@
 
 **Item**：`{ name: string, qty: int=1, specs: string[]\|null }`
 
-**Result（comparison_results 元素）**：`{ platform_id, platform_name, package, price(元,float\|null), is_source(bool), rank(int\|null), coupon_saved(元,float\|null) }`
+**Result（comparison_results 元素）**：`{ platform_id, platform_name, package, price(元,float\|null), is_source(bool), rank(int\|null), coupon_saved(元,float\|null), coupon_name(string\|null) }`
 
 - `coupon_saved`：该平台本单**平台主优惠额**（元）——美团红包 / 淘宝平台红包 / 京东优惠券·百亿补贴，**只取那一笔**，不含配送费减免/共减总额。仅外卖目标平台带值，源平台/没用为 `null`，前端记录页据此展示**「已优惠 ¥X」**（null 不展示）。
+- `coupon_name`：优惠**来源名**（展示用，best-effort）——美团「外卖大额神券」/ 京东「百亿补贴」/ 淘宝「平台红包」。仅在该行有 `coupon_saved` 时带；`null` 时前端走通用「红包」。非用户选中的具体券名（选中态不可读）。
 
 ## 服务端派生（客户端不用算）
 
diff --git a/docs/database/comparison_record.md b/docs/database/comparison_record.md
index d938618..ab58252 100644
--- a/docs/database/comparison_record.md
+++ b/docs/database/comparison_record.md
@@ -29,7 +29,7 @@
 | `status` | String(16) | NOT NULL, default `success` | `success`(拿到有效对比)/ `failed`(出错/没采到目标价) |
 | `information` | String(256) | nullable | done 帧文案;成功=摘要,失败=具体原因(前端失败时当原因展示) |
 | `items` | JSON(PG: JSONB) | NOT NULL, default [] | 下单菜品 `[{name, qty, specs?}]` |
-| `comparison_results` | JSON(PG: JSONB) | NOT NULL, default [] | 逐平台对比 `[{platform_id,platform_name,package,price(元),is_source,rank,coupon_saved}]`;`coupon_saved`=该平台主优惠额(元,美团红包/淘宝平台红包/京东优惠券·百亿补贴,只取那一笔,不含配送费/共减总额),各平台抠到红包即带值(2026-06 起源平台 Phase1 意图识别也抠,当前仅淘宝源),没用/没抠到为 null,前端展示「已优惠 ¥X」 |
+| `comparison_results` | JSON(PG: JSONB) | NOT NULL, default [] | 逐平台对比 `[{platform_id,platform_name,package,price(元),is_source,rank,coupon_saved,coupon_name}]`;`coupon_saved`=该平台主优惠额(元,美团红包/淘宝平台红包/京东优惠券·百亿补贴,只取那一笔,不含配送费/共减总额),各平台抠到红包即带值(2026-06 起源平台 Phase1 意图识别也抠,当前仅淘宝源),没用/没抠到为 null,前端展示「已优惠 ¥X」;`coupon_name`=优惠来源名(展示用 best-effort,美团"外卖大额神券"/京东"百亿补贴"/淘宝"平台红包"),null 走前端通用"红包" |
 | `skipped_dish_names` | JSON(PG: JSONB) | NOT NULL, default [] | 被跳过的菜名 |
 | `raw_payload` | JSON(PG: JSONB) | nullable | 客户端原始上报(calibration + done.params 全量) |
 | `created_at` | DateTime(tz) | server_default now(), index | 时间 |
diff --git a/tests/test_compare_record.py b/tests/test_compare_record.py
index 7ec7a19..1569d2f 100644
--- a/tests/test_compare_record.py
+++ b/tests/test_compare_record.py
@@ -33,7 +33,8 @@ def _food_payload(trace_id: str) -> dict:
         ],
         "comparison_results": [
             {"platform_id": "meituan", "platform_name": "美团", "package": "com.sankuai.meituan",
-             "price": 123.50, "is_source": False, "rank": 1, "coupon_saved": 7.0},
+             "price": 123.50, "is_source": False, "rank": 1,
+             "coupon_saved": 7.0, "coupon_name": "外卖大额神券"},
             {"platform_id": "taobao_flash", "platform_name": "淘宝闪购", "package": "com.taobao.taobao",
              "price": 128.50, "is_source": True, "rank": 2},
             {"platform_id": "jd_waimai", "platform_name": "京东外卖", "package": "com.jingdong.app.mall",
@@ -79,7 +80,7 @@ def test_report_and_derive(client) -> None:
 
 
 def test_coupon_saved_passthrough(client) -> None:
-    """红包优惠额 coupon_saved 上报→落库→读出;仅目标平台带值,源平台不带(null)。"""
+    """红包优惠额 coupon_saved + 来源名 coupon_name 上报→落库→读出;仅目标平台带值,源平台不带(null)。"""
     token = _login(client, "13800002010")
     rid = client.post(
         "/api/v1/compare/record", json=_food_payload("trace-coupon"), headers=_auth(token)
@@ -87,7 +88,9 @@ def test_coupon_saved_passthrough(client) -> None:
     d = client.get(f"/api/v1/compare/records/{rid}", headers=_auth(token)).json()
     by_pid = {x["platform_id"]: x for x in d["comparison_results"]}
     assert by_pid["meituan"]["coupon_saved"] == 7.0            # 目标平台带值
+    assert by_pid["meituan"]["coupon_name"] == "外卖大额神券"   # 来源名透传(pricebot#38)
     assert by_pid["taobao_flash"].get("coupon_saved") is None  # 源平台不带/为 null
+    assert by_pid["taobao_flash"].get("coupon_name") is None   # 源平台无来源名
 
 
 def test_source_is_cheapest_no_saving(client) -> None:
diff --git a/tests/test_welfare.py b/tests/test_welfare.py
index 1803815..79743ba 100644
--- a/tests/test_welfare.py
+++ b/tests/test_welfare.py
@@ -180,6 +180,51 @@ def test_exchange_flow(client) -> None:
     assert page["items"][0]["biz_type"] == "exchange_in"
 
 
+def test_exchange_min_floor_one_cent(client) -> None:
+    """锁定本次下调的兑换下限:正好兑下限额(MIN_EXCHANGE_COIN=100 金币=1 分)应成功。
+
+    这是本 PR 的核心新能力(下限 10000→100,可兑 1 分起)。test_exchange_flow 兑的是
+    1 元(10000),在旧下限下也通过,证明不了新下限;本用例供款并兑换正好等于下限的
+    100 金币,断言到账 1 分。若有人把 MIN_EXCHANGE_COIN 改回 10000,100 会因低于下限被
+    判 400,本用例随之失败,从而把新下限值钉死。
+    """
+    phone = "13800001010"
+    token = _login(client, phone)
+    # 供款: 正好注入一个下限额度的金币(=COIN_PER_CENT=100)
+    with SessionLocal() as db:
+        user = get_user_by_phone(db, phone)
+        assert user is not None
+        crud_wallet.grant_coins(
+            db, user.id, MIN_EXCHANGE_COIN, biz_type="test_seed", remark="测试供款"
+        )
+        db.commit()
+
+    # 兑换下限额 100 金币 → 1 分
+    r = client.post(
+        "/api/v1/wallet/exchange",
+        json={"coin_amount": MIN_EXCHANGE_COIN},
+        headers=_auth(token),
+    )
+    assert r.status_code == 200, r.text
+    res = r.json()
+    assert res["coin_amount"] == MIN_EXCHANGE_COIN
+    assert res["cash_added_cents"] == 1  # coins_to_cents(100) == 1
+    assert res["coin_balance"] == 0
+    assert res["cash_balance_cents"] == 1
+
+    # 金币流水有一笔 exchange_out(=-100)
+    r = client.get("/api/v1/wallet/coin-transactions", headers=_auth(token))
+    out_txn = next(t for t in r.json()["items"] if t["biz_type"] == "exchange_out")
+    assert out_txn["amount"] == -MIN_EXCHANGE_COIN
+
+    # 现金流水有且仅有一笔 exchange_in(=+1 分)
+    r = client.get("/api/v1/wallet/cash-transactions", headers=_auth(token))
+    cash = r.json()["items"]
+    assert len(cash) == 1
+    assert cash[0]["amount_cents"] == 1
+    assert cash[0]["biz_type"] == "exchange_in"
+
+
 def test_exchange_insufficient_and_invalid(client) -> None:
     token = _login(client, "13800001006")