了解 Claude
- 使用Claude构建
- 用例
- 上下文窗口
- 术语表
- 提示工程
智能体组件
- 工具
- 模型上下文协议 (MCP)
- 电脑使用(测试版)
- Google Sheets 插件
流式消息
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 提供了多种流式传输方式。Python SDK 同时支持同步和异步流。有关详细信息,请参阅各 SDK 的文档。
import anthropic
client = anthropic.Anthropic()
with client.messages.stream(
max_tokens=1024,
messages=[{"role": "user", "content": "Hello"}],
model="claude-opus-4-20250514",
) as stream:
for text in stream.text_stream:
print(text, end="", flush=True)
事件类型
每个服务器发送事件包括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:
message_start
:包含一个带有空content
的Message
对象。- 一系列内容块,每个块都有一个
content_block_start
,一个或多个content_block_delta
事件,以及一个content_block_stop
事件。每个内容块都有一个index
,对应于其在最终 Messagecontent
数组中的索引。 - 一个或多个
message_delta
事件,表示对最终Message
对象的顶层更改。 - 最后一个
message_stop
事件。
message_delta
事件中 usage
字段显示的令牌计数是累积的。
Ping 事件
事件流中可能还包含任意数量的 ping
事件。
错误事件
我们偶尔可能会在事件流中发送错误。例如,在高使用量期间,您可能会收到 overloaded_error
,这在非流式上下文中通常对应于 HTTP 529:
event: error
data: {"type": "error", "error": {"type": "overloaded_error", "message": "Overloaded"}}
其他事件
根据我们的版本控制政策,我们可能会添加新的事件类型,您的代码应该能够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 delta
,其类型会更新给定 index
处的 content
块。
文本增量
text
内容块增量如下所示:
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,它们提供了访问解析后的增量值的辅助工具。
tool_use
内容块增量如下所示:
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
中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 input
键和值被累积,我们会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的更细粒度。
思考增量
当使用启用了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:
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:
event: content_block_delta
data: {"type": "content_block_delta", "index": 0, "delta": {"type": "signature_delta", "signature": "EqQBCgIYAhIM1gbcDa9GJwZA2b3hGgxBdjrkzLoky3dl1pkiMOYds..."}}
完整的 HTTP 流响应
我们强烈建议在使用流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,则需要自己处理这些事件。
流响应由以下部分组成:
- 一个
message_start
事件 - 可能有多个内容块,每个块包含:
- 一个
content_block_start
事件 - 可能有多个
content_block_delta
事件 - 一个
content_block_stop
事件
- 一个
- 一个
message_delta
事件 - 一个
message_stop
事件
整个响应中可能还分散着 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-opus-4-20250514",
"messages": [{"role": "user", "content": "Hello"}],
"max_tokens": 256,
"stream": true
}'
event: message_start
data: {"type": "message_start", "message": {"id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY", "type": "message", "role": "assistant", "content": [], "model": "claude-opus-4-20250514", "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"}
带工具使用的流式请求
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-opus-4-20250514",
"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
}'
event: message_start
data: {"type":"message_start","message":{"id":"msg_014p7gG3wDgGV9EUtLvnow3U","type":"message","role":"assistant","model":"claude-3-haiku-20240307","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"}
带扩展思考的流式请求
在此请求中,我们启用了带流式传输的扩展思考,以查看 Claude 的逐步推理过程。
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-opus-4-20250514",
"max_tokens": 20000,
"stream": true,
"thinking": {
"type": "enabled",
"budget_tokens": 16000
},
"messages": [
{
"role": "user",
"content": "What is 27 * 453?"
}
]
}'
event: message_start
data: {"type": "message_start", "message": {"id": "msg_01...", "type": "message", "role": "assistant", "content": [], "model": "claude-opus-4-20250514", "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"}
带网络搜索工具使用的流式请求
event: message_start
data: {"type":"message_start","message":{"id":"msg_01G...","type":"message","role":"assistant","model":"claude-3-7-sonnet-20250219","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"}