diff --git a/app/service/memory_extraction_service.py b/app/service/memory_extraction_service.py
index 0286f3d..31a9fef 100644
--- a/app/service/memory_extraction_service.py
+++ b/app/service/memory_extraction_service.py
@@ -163,8 +163,20 @@ class MemoryExtractionService:
             candidate = candidate.removeprefix("```")
             candidate = candidate.removeprefix("json").removesuffix("```").strip()
         try:
-            return _ExtractionPayload.model_validate(json.loads(candidate))
-        except (json.JSONDecodeError, ValidationError, TypeError) as exc:
+            data = json.loads(candidate)
+        except (json.JSONDecodeError, TypeError) as exc:
+            raise RecoverableAgentError("模型记忆抽取输出不是有效 JSON") from exc
+        # 模型有时把结果包在**单元素数组**里，而契约是**对象**。实测出现于 episode 抽取路径：
+        #     [{"memory_key": null, "value": null, "memory_type": null, "confidence": 0}]
+        # 该形状此前直接进 pydantic 校验、报 `Input should be a valid dictionary`，
+        # 被记成"输出不是有效 JSON"并反复重试直到 episode 判失败 —— 而它其实是**合法的空结果**
+        # （`_validate` 已能把"三字段为 null 且 confidence=0"识别为"无持久事实"）。
+        # 只归一化"恰好一个对象的数组"；多元素或元素非对象时**不猜**，仍交给校验失败关闭。
+        if isinstance(data, list) and len(data) == 1 and isinstance(data[0], dict):
+            data = data[0]
+        try:
+            return _ExtractionPayload.model_validate(data)
+        except (ValidationError, TypeError) as exc:
             raise RecoverableAgentError("模型记忆抽取输出不是有效 JSON") from exc
 
     def _validate(
diff --git a/tests/unit/service/test_memory_extraction_service.py b/tests/unit/service/test_memory_extraction_service.py
index c06a57a..ac93368 100644
--- a/tests/unit/service/test_memory_extraction_service.py
+++ b/tests/unit/service/test_memory_extraction_service.py
@@ -161,6 +161,39 @@ async def test_declared_empty_extraction_returns_none() -> None:
         await extract_with(json.dumps({**payload, "confidence": 0.5}))
 
 
+@pytest.mark.asyncio
+async def test_single_element_array_is_normalized() -> None:
+    """模型把结果包在**单元素数组**里时归一化为对象，而不是当成"无效 JSON"。
+
+    背景（2026-09-12 实测）：契约是对象，但模型在 episode 抽取路径会返回
+    `[{"memory_key": null, "value": null, "memory_type": null, "confidence": 0}]`。
+    该形状此前直接进 pydantic 校验，报
+    `Input should be a valid dictionary ... input_type=list`，被记成"输出不是有效 JSON"，
+    于是反复重试到 episode 判失败 —— 而它其实是**合法的空结果**。
+    """
+    empty = {"memory_key": None, "value": None, "memory_type": None, "confidence": 0}
+    # 数组包着的空结果 → 归一化后按"无持久事实"处理，返回 None（不是失败）。
+    assert await extract_with(json.dumps([empty])) is None
+    # 数组包着的**有事实**结果 → 同样归一化，照常解析出来。
+    extracted = await extract_with(json.dumps([VALID_PAYLOAD]))
+    assert extracted is not None
+    assert extracted.memory_key == VALID_PAYLOAD["memory_key"]
+
+
+@pytest.mark.asyncio
+async def test_multi_element_or_non_dict_array_still_fails_closed() -> None:
+    """只归一化"恰好一个对象的数组"；其余形状**不猜**，仍失败关闭。
+
+    多元素时无法判断哪一个是答案，猜错会把错误记忆写进库 —— 比失败更糟。
+    """
+    with pytest.raises(RecoverableAgentError):
+        await extract_with(json.dumps([VALID_PAYLOAD, VALID_PAYLOAD]))
+    with pytest.raises(RecoverableAgentError):
+        await extract_with(json.dumps(["not-a-dict"]))
+    with pytest.raises(RecoverableAgentError):
+        await extract_with(json.dumps([]))
+
+
 @pytest.mark.asyncio
 async def test_missing_endpoint_fails_closed_without_calling_model() -> None:
     service, model = build_service(json.dumps(VALID_PAYLOAD), resolver=StubResolver([]))