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    第一步

    Claude 简介快速开始

    模型与定价

    模型概览选择模型Claude 4.5 的新功能迁移到 Claude 4.5模型弃用定价

    使用 Claude 构建

    功能概览使用 Messages API上下文窗口提示词最佳实践

    功能

    提示词缓存上下文编辑扩展思考流式消息批处理引用多语言支持Token 计数嵌入向量视觉PDF 支持Files API搜索结果Google Sheets 插件

    工具

    概述如何实现工具使用令牌高效的工具使用细粒度工具流式传输Bash 工具代码执行工具计算机使用工具文本编辑器工具Web fetch 工具网络搜索工具记忆工具

    代理技能

    概述在 API 中开始使用 Agent Skills技能创作最佳实践通过 API 使用 Agent Skills

    Agent SDK

    概览TypeScript SDKPython SDK

    指南

    流式输入处理权限会话管理托管 Agent SDK修改系统提示词SDK 中的 MCP自定义工具SDK 中的子代理SDK 中的斜杠命令SDK 中的代理技能跟踪成本和使用情况待办事项列表SDK 中的插件

    API 中的 MCP

    MCP 连接器远程 MCP 服务器

    Claude 在第三方平台上

    Amazon BedrockVertex AI

    提示词工程

    概述提示词生成器使用提示模板提示词改进器保持清晰和直接使用示例（多示例提示）让 Claude 思考（思维链）使用XML标签给Claude分配角色（系统提示）预填充 Claude 的响应链式复杂提示长文本技巧扩展思考技巧

    测试与评估

    定义成功标准开发测试用例使用评估工具减少延迟

    加强防护措施

    减少幻觉提高输出一致性缓解越狱handle-streaming-refusals减少提示词泄露保持Claude的角色特征

    管理和监控

    Admin API 概述使用量和成本 APIClaude Code 分析 API
    Console
    功能

    流式消息

    了解如何使用服务器发送事件(SSE)增量流式传输Claude的响应。

    在创建消息时，您可以设置 "stream": true 来使用服务器发送事件 (SSE) 增量流式传输响应。

    使用SDK进行流式传输

    我们的Python和TypeScript SDK提供多种流式传输方式。Python SDK支持同步和异步流。有关详细信息，请参阅每个SDK中的文档。

    Python
    import anthropic

client = anthropic.Anthropic()

with client.messages.stream(
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello"}],
    model="claude-sonnet-4-5",
) as stream:
  for text in stream.text_stream:
      print(text, end="", flush=True)
    TypeScript
    import Anthropic from '@anthropic-ai/sdk';

const client = new Anthropic();

await client.messages.stream({
    messages: [{role: 'user', content: "Hello"}],
    model: 'claude-sonnet-4-5',
    max_tokens: 1024,
}).on('text', (text) => {
    console.log(text);
});

    事件类型

    每个服务器发送事件都包含一个命名的事件类型和相关的JSON数据。每个事件将使用SSE事件名称（例如 event: message_stop），并在其数据中包含匹配的事件 type。

    每个流使用以下事件流程：

    1. message_start：包含一个具有空 content 的 Message 对象。
    2. 一系列内容块，每个内容块都有一个 content_block_start、一个或多个 content_block_delta 事件和一个 content_block_stop 事件。每个内容块都有一个 index，对应于其在最终Message content 数组中的索引。
    3. 一个或多个 message_delta 事件，指示对最终 Message 对象的顶级更改。
    4. 最终的 message_stop 事件。

    message_delta 事件的 usage 字段中显示的令牌计数是累积的。

    Ping事件

    事件流还可能包含任意数量的 ping 事件。

    错误事件

    我们可能偶尔在事件流中发送错误。例如，在高使用率期间，您可能会收到 overloaded_error，这通常对应于非流式上下文中的HTTP 529：

    Example error
    event: error
data: {"type": "error", "error": {"type": "overloaded_error", "message": "Overloaded"}}

    其他事件

    根据我们的版本控制策略，我们可能会添加新的事件类型，您的代码应该优雅地处理未知的事件类型。

    内容块增量类型

    每个 content_block_delta 事件包含一个类型的 delta，用于更新给定 index 处的 content 块。

    文本增量

    text 内容块增量如下所示：

    Text delta
    event: content_block_delta
data: {"type": "content_block_delta","index": 0,"delta": {"type": "text_delta", "text": "ello frien"}}

    输入JSON增量

    tool_use 内容块的增量对应于块的 input 字段的更新。为了支持最大粒度，增量是_部分JSON字符串_，而最终的 tool_use.input 始终是一个_对象_。

    您可以累积字符串增量，并在收到 content_block_stop 事件后解析JSON，方法是使用像Pydantic这样的库进行部分JSON解析，或者使用我们的SDK，它们提供帮助程序来访问解析的增量值。

    tool_use 内容块增量如下所示：

    Input JSON delta
    event: content_block_delta
data: {"type": "content_block_delta","index": 1,"delta": {"type": "input_json_delta","partial_json": "{\"location\": \"San Fra"}}}

    注意：我们当前的模型仅支持一次从 input 发出一个完整的键和值属性。因此，在使用工具时，模型工作期间流式事件之间可能会有延迟。一旦累积了 input 键和值，我们将它们作为多个带有分块部分json的 content_block_delta 事件发出，以便格式可以自动支持未来模型中更细的粒度。

    思考增量

    当使用启用流式传输的扩展思考时，您将通过 thinking_delta 事件接收思考内容。这些增量对应于 thinking 内容块的 thinking 字段。

    对于思考内容，在 content_block_stop 事件之前会发送一个特殊的 signature_delta 事件。此签名用于验证思考块的完整性。

    典型的思考增量如下所示：

    Thinking delta
    event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "Let me solve this step by step:\n\n1. First break down 27 * 453"}}

    签名增量如下所示：

    Signature delta
    event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "signature_delta", "signature": "EqQBCgIYAhIM1gbcDa9GJwZA2b3hGgxBdjrkzLoky3dl1pkiMOYds..."}}

    完整的HTTP流响应

    我们强烈建议您在使用流式模式时使用我们的客户端SDK。但是，如果您正在构建直接的API集成，您将需要自己处理这些事件。

    流响应由以下部分组成：

    1. 一个 message_start 事件
    2. 可能有多个内容块，每个内容块包含：
      • 一个 content_block_start 事件
      • 可能有多个 content_block_delta 事件
      • 一个 content_block_stop 事件
    3. 一个 message_delta 事件
    4. 一个 message_stop 事件

    整个响应中也可能分散有 ping 事件。有关格式的更多详细信息，请参阅事件类型。

    基本流式请求

    curl https://api.anthropic.com/v1/messages \
     --header "anthropic-version: 2023-06-01" \
     --header "content-type: application/json" \
     --header "x-api-key: $ANTHROPIC_API_KEY" \
     --data \
'{
  "model": "claude-sonnet-4-5",
  "messages": [{"role": "user", "content": "Hello"}],
  "max_tokens": 256,
  "stream": true
}'
    Response
    event: message_start
data: {"type": "message_start", "message": {"id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY", "type": "message", "role": "assistant", "content": [], "model": "claude-sonnet-4-5-20250929", "stop_reason": null, "stop_sequence": null, "usage": {"input_tokens": 25, "output_tokens": 1}}}

event: content_block_start
data: {"type": "content_block_start", "index": 0, "content_block": {"type": "text", "text": ""}}

event: ping
data: {"type": "ping"}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "text_delta", "text": "Hello"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "text_delta", "text": "!"}}

event: content_block_stop
data: {"type": "content_block_stop", "index": 0}

event: message_delta
data: {"type": "message_delta", "delta": {"stop_reason": "end_turn", "stop_sequence":null}, "usage": {"output_tokens": 15}}

event: message_stop
data: {"type": "message_stop"}

    使用工具的流式请求

    工具使用现在支持参数值的细粒度流式传输作为测试功能。有关更多详细信息，请参阅细粒度工具流式传输。

    在此请求中，我们要求Claude使用工具告诉我们天气情况。

      curl https://api.anthropic.com/v1/messages \
    -H "content-type: application/json" \
    -H "x-api-key: $ANTHROPIC_API_KEY" \
    -H "anthropic-version: 2023-06-01" \
    -d '{
      "model": "claude-sonnet-4-5",
      "max_tokens": 1024,
      "tools": [
        {
          "name": "get_weather",
          "description": "Get the current weather in a given location",
          "input_schema": {
            "type": "object",
            "properties": {
              "location": {
                "type": "string",
                "description": "The city and state, e.g. San Francisco, CA"
              }
            },
            "required": ["location"]
          }
        }
      ],
      "tool_choice": {"type": "any"},
      "messages": [
        {
          "role": "user",
          "content": "What is the weather like in San Francisco?"
        }
      ],
      "stream": true
    }'
    Response
    event: message_start
data: {"type":"message_start","message":{"id":"msg_014p7gG3wDgGV9EUtLvnow3U","type":"message","role":"assistant","model":"claude-sonnet-4-5-20250929","stop_sequence":null,"usage":{"input_tokens":472,"output_tokens":2},"content":[],"stop_reason":null}}

event: content_block_start
data: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}

event: ping
data: {"type": "ping"}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"Okay"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":","}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" let"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"'s"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" check"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" the"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" weather"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" for"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" San"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" Francisco"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":","}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" CA"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":":"}}

event: content_block_stop
data: {"type":"content_block_stop","index":0}

event: content_block_start
data: {"type":"content_block_start","index":1,"content_block":{"type":"tool_use","id":"toolu_01T1x1fJ34qAmk2tNTrN7Up6","name":"get_weather","input":{}}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"{\"location\":"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":" \"San"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":" Francisc"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"o,"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":" CA\""}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":", "}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"\"unit\": \"fah"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"renheit\"}"}}

event: content_block_stop
data: {"type":"content_block_stop","index":1}

event: message_delta
data: {"type":"message_delta","delta":{"stop_reason":"tool_use","stop_sequence":null},"usage":{"output_tokens":89}}

event: message_stop
data: {"type":"message_stop"}

    使用扩展思考的流式请求

    在此请求中，我们启用带有流式传输的扩展思考，以查看Claude的逐步推理。

    curl https://api.anthropic.com/v1/messages \
     --header "x-api-key: $ANTHROPIC_API_KEY" \
     --header "anthropic-version: 2023-06-01" \
     --header "content-type: application/json" \
     --data \
'{
    "model": "claude-sonnet-4-5",
    "max_tokens": 20000,
    "stream": true,
    "thinking": {
        "type": "enabled",
        "budget_tokens": 16000
    },
    "messages": [
        {
            "role": "user",
            "content": "What is 27 * 453?"
        }
    ]
}'
    Response
    event: message_start
data: {"type": "message_start", "message": {"id": "msg_01...", "type": "message", "role": "assistant", "content": [], "model": "claude-sonnet-4-5-20250929", "stop_reason": null, "stop_sequence": null}}

event: content_block_start
data: {"type": "content_block_start", "index": 0, "content_block": {"type": "thinking", "thinking": ""}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "Let me solve this step by step:\n\n1. First break down 27 * 453"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "\n2. 453 = 400 + 50 + 3"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "\n3. 27 * 400 = 10,800"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "\n4. 27 * 50 = 1,350"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "\n5. 27 * 3 = 81"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "thinking_delta", "thinking": "\n6. 10,800 + 1,350 + 81 = 12,231"}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "signature_delta", "signature": "EqQBCgIYAhIM1gbcDa9GJwZA2b3hGgxBdjrkzLoky3dl1pkiMOYds..."}}

event: content_block_stop
data: {"type": "content_block_stop", "index": 0}

event: content_block_start
data: {"type": "content_block_start", "index": 1, "content_block": {"type": "text", "text": ""}}

event: content_block_delta
data: {"type": "content_block_delta", "index": 1, "delta": {"type": "text_delta", "text": "27 * 453 = 12,231"}}

event: content_block_stop
data: {"type": "content_block_stop", "index": 1}

event: message_delta
data: {"type": "message_delta", "delta": {"stop_reason": "end_turn", "stop_sequence": null}}

event: message_stop
data: {"type": "message_stop"}

    使用网络搜索工具的流式请求

    在此请求中，我们要求Claude搜索网络以获取当前天气信息。

    curl https://api.anthropic.com/v1/messages \
     --header "x-api-key: $ANTHROPIC_API_KEY" \
     --header "anthropic-version: 2023-06-01" \
     --header "content-type: application/json" \
     --data \
'{
    "model": "claude-sonnet-4-5",
    "max_tokens": 1024,
    "stream": true,
    "tools": [
        {
            "type": "web_search_20250305",
            "name": "web_search",
            "max_uses": 5
        }
    ],
    "messages": [
        {
            "role": "user",
            "content": "What is the weather like in New York City today?"
        }
    ]
}'
    Response
    event: message_start
data: {"type":"message_start","message":{"id":"msg_01G...","type":"message","role":"assistant","model":"claude-sonnet-4-5-20250929","content":[],"stop_reason":null,"stop_sequence":null,"usage":{"input_tokens":2679,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"output_tokens":3}}}

event: content_block_start
data: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"I'll check"}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":" the current weather in New York City for you"}}

event: ping
data: {"type": "ping"}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"."}}

event: content_block_stop
data: {"type":"content_block_stop","index":0}

event: content_block_start
data: {"type":"content_block_start","index":1,"content_block":{"type":"server_tool_use","id":"srvtoolu_014hJH82Qum7Td6UV8gDXThB","name":"web_search","input":{}}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"{\"query"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"\":"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":" \"weather"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":" NY"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"C to"}}

event: content_block_delta
data: {"type":"content_block_delta","index":1,"delta":{"type":"input_json_delta","partial_json":"day\"}"}}

event: content_block_stop
data: {"type":"content_block_stop","index":1 }

event: content_block_start
data: {"type":"content_block_start","index":2,"content_block":{"type":"web_search_tool_result","tool_use_id":"srvtoolu_014hJH82Qum7Td6UV8gDXThB","content":[{"type":"web_search_result","title":"Weather in New York City in May 2025 (New York) - detailed Weather Forecast for a month","url":"https://world-weather.info/forecast/usa/new_york/may-2025/","encrypted_content":"Ev0DCioIAxgCIiQ3NmU4ZmI4OC1k...","page_age":null},...]}}

event: content_block_stop
data: {"type":"content_block_stop","index":2}

event: content_block_start
data: {"type":"content_block_start","index":3,"content_block":{"type":"text","text":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":3,"delta":{"type":"text_delta","text":"Here's the current weather information for New York"}}

event: content_block_delta
data: {"type":"content_block_delta","index":3,"delta":{"type":"text_delta","text":" City:\n\n# Weather"}}

event: content_block_delta
data: {"type":"content_block_delta","index":3,"delta":{"type":"text_delta","text":" in New York City"}}

event: content_block_delta
data: {"type":"content_block_delta","index":3,"delta":{"type":"text_delta","text":"\n\n"}}

...

event: content_block_stop
data: {"type":"content_block_stop","index":17}

event: message_delta
data: {"type":"message_delta","delta":{"stop_reason":"end_turn","stop_sequence":null},"usage":{"input_tokens":10682,"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"output_tokens":510,"server_tool_use":{"web_search_requests":1}}}

event: message_stop
data: {"type":"message_stop"}

    错误恢复

    当流式请求因网络问题、超时或其他错误而中断时，您可以通过从流中断的地方恢复来进行恢复。这种方法可以避免重新处理整个响应。

    基本恢复策略包括：

    1. 捕获部分响应：保存在发生错误之前成功接收的所有内容
    2. 构造继续请求：创建一个新的API请求，将部分助手响应作为新助手消息的开始
    3. 恢复流式传输：从中断的地方继续接收响应的其余部分

    错误恢复最佳实践

    1. 使用SDK功能：利用SDK的内置消息累积和错误处理功能
    2. 处理内容类型：请注意消息可以包含多个内容块（text、tool_use、thinking）。工具使用和扩展思考块无法部分恢复。您可以从最近的文本块恢复流式传输。
    • 使用SDK进行流式传输
    • Ping事件
    • 输入JSON增量
    • 完整的HTTP流响应
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