# 要求结构化输出
<a name="prompting-structured-output"></a>

为确保输出格式的一致性和结构化，您可以使用*结构化输出*，包括 XML、JSON 或 Markdown 等格式。这种方法可使下游应用场景更有效地使用和处理模型生成的输出。向模型提供明确指令，生成的回复将以符合预定义架构的方式呈现。建议为模型提供要遵循的 `output schema`。

例如，若下游解析器希望 JSON 对象的键名遵循特定命名约定，则须在查询的**输出架构**字段中指定该约定。此外，如果希望回复以 JSON 格式呈现，且不带任何前言文本，则须相应地向模型提供指令。也是就明确指示“**请仅生成 JSON 格式的输出内容。切勿添加任何前言内容。**”。

**通过预填充引导模型生成**

通过预填充 `assistant` 内容*引导*模型回复是一种行之有效的替代方案。此技术有助于引导模型的行为，跳过前言内容，并强制生成特定的输出格式，例如 JSON 和 XML。例如，若使用 `"{"` 或 `"```json"` 预填充助手回复内容，则该输入可引导模型直接生成 JSON 对象，无需提供其他信息。

**提示**  
如果明确表示需要提取 JSON 内容，常见做法是使用 ````json` 进行预填充并在 `````处上添加停止序列。此操作可确保模型输出能够以编程方式解析的 JSON 对象。

以下是一些常见格式架构的示例。

------
#### [ JSON ]

```
JSON_schema = """Make sure your final response is a valid JSON schema follow the below Response Schema:

##Response Schema:
```json
{ 
"key1": "value1",
"key2": "value2",
key3: [{
"key3_1": "value_3_1,
"key3_2": "value_3_2,
...}```
"""
```

------
#### [ XML ]

```
XML_format = """Make sure your final response is a valid XML schema follow the below Response Schema:
##Response Schema:
<thinking>
( your thoughts go hee )
</thinking>
<output>
    <task>"task1"</task>
    <subtask>
    <task1_result> ( task 1 result )</task1_result>
    <task2_result> ( task 2 result )</task2_result>
    <task3_result> ( task 3 result )</task3_result>
    </subtask>
    <task>"task2"</task>
    <subtask>
    <task1_result> ( task 1 result )</task1_result>
    <task2_result> ( task 2 result )</task2_result>
    <task3_result> ( task 3 result )</task3_result>
    </subtask>
</output>

"""
```

------
#### [ Markdown ]

```
markdown_schema = """Make sure your final response is a valid Markdown schema follow the below Response Schema:

##Response Schema:
## Introduction
( 2-3 line intro)

## Design Guidance 
(Bulleted list of design guidance)

## Step by Step Instructions on Execution
( Bulleted list of instructions with each with bold title.

## Conclusion
( conclusion )


"""
```

------

以下代码演示了如何使用 API 进行预填充：

```
import boto3
import json

# Create a Bedrock Runtime client.
client = boto3.client(
    "bedrock-runtime",
    region_name="us-east-1"
)

request_body = {
    "system": [
        {"text": "You write JSON objects based on the given instructions"}
    ],
    "messages": [
        {
            "role": "user",
            "content": [{"text": "Provide details about the best selling full-frame cameras in past three years.
Answer in JSON format with keys like name, brand, price and a summary."}]
        },
        {
            "role": "assistant",
            "content": [{"text": " Here is the JSON response: ```json"}]
        },
    ],
    "inferenceConfig": {
        "maxTokens": 300,
        "temperature": 0,
    }
}

# Invoke the model and extract the response body.
response = client.invoke_model(
    modelId="amazon.nova-micro-v1:0",
    body=json.dumps(request_body)
)
model_response = json.loads(response["body"].read())
```

**注意**  
对于结构化输出，无论您是否利用工具，我们都建议使用贪婪解码参数。即：`temperature=0`。

## 示例 1：添加输出架构
<a name="structure-collapsible1"></a>

向“输出架构”部分添加恰当的架构可引导模型遵循该架构生成内容。然而，模型输出具有不确定性，可能与输出架构存在差异。


| 角色 |  | 提示 | 
| --- |--- |--- |
| 用户 | 提供过去三年最畅销的全画幅相机的详细信息。以 JSON 格式作答，且应包含名称、品牌、价格和摘要等关键字。 | 提供过去三年最畅销的全画幅相机的详细信息。必须仅以 JSON 格式作答。请遵循下方输出架构。<br />**输出架构：**<pre>[{<br />    "name": "name goes here",<br />    "brand": "brand goes here",<br />    "price": "price goes here",<br />    "summary": "summary goes here"<br />}]</pre> | 
| 助手 |  <pre>[<br /> {<br /> "name": "Sony Alpha A7R IV",<br /> "brand": "Sony",<br /> "price": "Approximately $3,500",<br /> "summary": "The Sony Alpha A7R IV is renowned for its<br /> exceptional image quality, thanks to a 61-megapixel<br /> full-frame sensor. It also features 4K video recording<br /> and a robust build, making it a favorite among professional<br /> photographers and videographers."<br /> },<br /> {<br /> "name": "Canon EOS R5",<br /> "brand": "Canon",<br /> "price": "Approximately $3,900",<br /> "summary": "The Canon EOS R5 combines high-resolution<br /> imaging with advanced video capabilities. It houses a<br /> 45-megapixel sensor, 8K video recording, and impressive<br /> autofocus performance, appealing to both photography<br /> and filmmaking professionals."<br /> },<br /> {<br /> "name": "Nikon Z7 II",<br /> "brand": "Nikon",<br /> "price": "Approximately $2,800",<br /> "summary": "The Nikon Z7 II offers a 45.7-megapixel<br /> full-frame sensor and is praised for its high resolution<br /> and excellent dynamic range. It also supports 4K video<br /> recording and features a versatile Z-mount lens system,<br /> making it a strong contender in the full-frame market."<br /> },<br /> {<br /> "name": "Fujifilm GFX 100S",<br /> "brand": "Fujifilm",<br /> "price": "Approximately $7,000",<br /> "summary": "While not a traditional full-frame camera,<br /> the Fujifilm GFX 100S stands out with its 102-megapixel<br /> medium format sensor. It is lauded for its stunning detail<br /> and color reproduction, though it comes at a higher price<br /> point and is aimed at specialized users."<br /> }<br /> ]</pre>  |  <pre>[<br /> {<br /> "name": "Nikon D850",<br /> "brand": "Nikon",<br /> "price": "$3,296.95",<br /> "summary": "The Nikon D850 is a professional full-frame<br /> DSLR camera known for its exceptional image quality,<br /> 45.7-megapixel resolution, 7 fps continuous shooting,<br /> and 4K video capabilities."<br /> },<br /> {<br /> "name": "Canon EOS 5D Mark IV",<br /> "brand": "Canon",<br /> "price": "$3,499.00",<br /> "summary": "The Canon EOS 5D Mark IV is a popular<br /> full-frame DSLR appreciated for its 30.4-megapixel sensor,<br /> 4K video recording, robust build quality, and reliable<br /> autofocus system."<br /> },<br /> {<br /> "name": "Sony A7R III",<br /> "brand": "Sony",<br /> "price": "$3,198.00",<br /> "summary": "The Sony A7R III is a high-resolution<br /> full-frame mirrorless camera renowned for its 42.4-megapixel<br /> sensor, excellent low-light performance, and versatile<br /> lens compatibility."<br /> },<br /> {<br /> "name": "Fujifilm GFX 100S",<br /> "brand": "Fujifilm",<br /> "price": "$5,999.99",<br /> "summary": "The Fujifilm GFX 100S is a medium format<br /> mirrorless camera that stands out for its 102-megapixel<br /> sensor, high dynamic range, and exceptional color reproduction."<br /> },<br /> {<br /> "name": "Sony A7 III",<br /> "brand": "Sony",<br /> "price": "$1,998.00",<br /> "summary": "The Sony A7 III is a full-frame mirrorless<br /> camera popular among enthusiasts and professionals for<br /> its 24.2-megapixel sensor, fast autofocus, and 4K video<br /> capabilities."<br /> }<br /> ]</pre>  | 

## 示例 2：预填充模型回复
<a name="structure-collapsible2"></a>

第二种方法是在助手消息中包含所需的初始文本，从而预填充模型的回复。在这种情况下，Amazon Nova 模型将从助手消息中断处继续回复。


| 角色 | 提示 | 
| --- |--- |
| 用户 | 提供过去三年最畅销的全画幅相机的详细信息。回复须采用 JSON 格式，并包含以下关键字：名称、品牌、年份、价格、摘要。 | 
| 助手*（预填充*） | ```json | 
| 助手 |  <pre>{<br /> "cameras": [<br /> {<br /> "name": "Sony Alpha A7 III",<br /> "brand": "Sony",<br /> "year": 2018,<br /> "price": "$1999",<br /> "summary": "The Sony Alpha A7 III is a highly acclaimed<br /> full-frame mirrorless camera known for its excellent<br /> image quality, advanced autofocus system, and 4K video<br /> capabilities."<br /> },<br /> {<br /> "name": "Canon EOS R5",<br /> "brand": "Canon",<br /> "year": 2020,<br /> "price": "$3899",<br /> "summary": "The Canon EOS R5 is a top-tier full-frame<br /> mirrorless camera that offers stunning 45MP images, 8K<br /> video recording, and exceptional performance in various<br /> lighting conditions."<br /> },<br /> {<br /> "name": "Nikon Z7 II",<br /> "brand": "Nikon",<br /> "year": 2020,<br /> "price": "$2999",<br /> "summary": "The Nikon Z7 II is a flagship full-frame<br /> mirrorless camera with a 45.7MP sensor, superb image<br /> quality, and advanced video recording features."<br /> },<br /> {<br /> "name": "Fujifilm GFX 100S",<br /> "brand": "Fujifilm",<br /> "year": 2020,<br /> "price": "$7999",<br /> "summary": "The Fujifilm GFX 100S is a medium format<br /> mirrorless camera known for its impressive 102MP sensor,<br /> beautiful film simulations, and versatile lens options."<br /> },<br /> {<br /> "name": "Sony Alpha A7R IV",<br /> "brand": "Sony",<br /> "year": 2019,<br /> "price": "$3499",<br /> "summary": "The Sony Alpha A7R IV features a 61MP<br /> sensor, excellent low-light performance, and advanced<br /> video capabilities, making it a favorite among<br /> professional photographers."<br /> }<br /> ]<br /> }<br /> ```</pre>  | 

## 示例 3：指定使用工具
<a name="structure-collapsible3"></a>

第三种方法是使用“工具使用”，通过在“工具使用”架构部分中包含 *pydantic JSON 架构*来强制模型回复遵循特定架构。可为所提供架构指定*工具选择*，这样 Amazon Nova 就会根据所选工具的架构生成回复。要了解如何利用“工具使用”功能的更多信息，请参阅[Amazon Nova 的“工具使用”（函数调用）](tool-use.md)。


|  |  | 
| --- |--- |
| 用户 | 从下方提供的查询中提取相关实体<pre>Query: John works in BUILDING-0987<br />and has been in charge of product id 23564#.<br />His performance has been excellent in past<br />year and he is up for a raise.<br /><br />Use the print_entities tool.</pre> | 
| ToolConfig |  <pre>tool_config = {<br />    "tools": [<br />        {<br />            "toolSpec": {<br />                    "name": "print_entities",<br />                    "description": "Extract the named entity based on provided input",<br />                    "inputSchema": {<br />                        "type": "object",<br />                        "properties": {<br />                            "name": {<br />                               "type": "string",<br />                               "description": "The extracted entity name. This should be a name of a person, place, animal or thing"<br />                            },<br />                            "location": {<br />                               "type": "string",<br />                                "description": "The extracted location name. This is a site name or a building name like SITE-001 or BUILDING-003"<br />                            },<br />                            "product": {<br />                              "type": "string",<br />                              "description": "The extracted product code, this is generally a 6 digit alphanumeric code such as 45623#, 234567"<br />                            }<br />                        },<br />                        "required": ["name", "location", "product"]<br />                 }<br />            }<br />        }<br />    ],<br />    "toolChoice": {<br />        "tool": {<br />            "name": "print_entities"<br />        }<br />    }<br />}</pre>  |