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agent-sdk/streaming-output.md 2026-06-16 21:57 UTC to 2026-06-17 17:02 UTC

2 added, 1 removed.

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即時串流回應

當文字和工具呼叫串流進來時,從 Agent SDK 取得即時回應

根據預設,Agent SDK 會在 Claude 完成生成每個回應後產生完整的 AssistantMessage 物件。若要在文字和工具呼叫生成時接收增量更新,請在選項中將 include_partial_messages(Python)或 includePartialMessages(TypeScript)設定為 true 來啟用部分訊息串流。

啟用串流輸出

若要啟用串流,請在選項中將 include_partial_messages(Python)或 includePartialMessages(TypeScript)設定為 true。這會導致 SDK 產生包含原始 API 事件的 StreamEvent 訊息(當它們到達時),以及通常的 AssistantMessageResultMessage

您的程式碼需要:

  1. 檢查每個訊息的類型以區分 StreamEvent 和其他訊息類型
  2. 對於 StreamEvent,提取 event 欄位並檢查其 type
  3. 尋找 content_block_delta 事件,其中 delta.typetext_delta,其中包含實際的文字區塊

下面的範例啟用串流並在文字區塊到達時列印它們。注意巢狀類型檢查:首先是 StreamEvent,然後是 content_block_delta,然後是 text_delta

from claude_agent_sdk import query, ClaudeAgentOptions
from claude_agent_sdk.types import StreamEvent
import asyncio


async def stream_response():
options = ClaudeAgentOptions(
include_partial_messages=True,
allowed_tools=["Bash", "Read"],
)

async for message in query(prompt="List the files in my project", options=options):
if isinstance(message, StreamEvent):
event = message.event
if event.get("type") == "content_block_delta":
delta = event.get("delta", {})
if delta.get("type") == "text_delta":
print(delta.get("text", ""), end="", flush=True)


asyncio.run(stream_response())

StreamEvent 參考

啟用部分訊息時,您會收到包裝在物件中的原始 Claude API 串流事件。該類型在每個 SDK 中有不同的名稱:

  • PythonStreamEvent(從 claude_agent_sdk.types 匯入)
  • TypeScriptSDKPartialAssistantMessage,其中 type: 'stream_event'

兩者都包含原始 Claude API 事件,而不是累積的文字。您需要自己提取和累積文字增量。以下是每種類型的結構:

@dataclass
class StreamEvent:
uuid: str  # Unique identifier for this event
session_id: str  # Session identifier
event: dict[str, Any]  # The raw Claude API stream event
parent_tool_use_id: str | None  # Parent tool ID if from a subagent

event 欄位包含來自 Claude API 的原始串流事件。常見的事件類型包括:

事件類型 說明
message_start 新訊息的開始
content_block_start 新內容區塊的開始(文字或工具使用)
content_block_delta 內容的增量更新
content_block_stop 內容區塊的結束
message_delta 訊息層級的更新(停止原因、使用情況)
message_stop 訊息的結束

訊息流

啟用部分訊息後,您會按此順序接收訊息:

StreamEvent (message_start)
StreamEvent (content_block_start) - text block
StreamEvent (content_block_delta) - text chunks...
StreamEvent (content_block_stop)
StreamEvent (content_block_start) - tool_use block
StreamEvent (content_block_delta) - tool input chunks...
StreamEvent (content_block_stop)
StreamEvent (message_delta)
StreamEvent (message_stop)
AssistantMessage - complete message with all content
... tool executes ...
... more streaming events for next turn ...
ResultMessage - final result

未啟用部分訊息(Python 中的 include_partial_messages、TypeScript 中的 includePartialMessages)時,您會收到除 StreamEvent 外的所有訊息類型。常見類型包括 SystemMessage(工作階段初始化)、AssistantMessage(完整回應)、ResultMessage(最終結果)和指示何時壓縮對話歷史記錄的緊湊邊界訊息(TypeScript 中的 SDKCompactBoundaryMessage;Python 中具有子類型 "compact_boundary"SystemMessage)。

串流文字回應

若要在生成文字時顯示它,請尋找 content_block_delta 事件,其中 delta.typetext_delta。這些包含增量文字區塊。下面的範例在每個區塊到達時列印它:

from claude_agent_sdk import query, ClaudeAgentOptions
from claude_agent_sdk.types import StreamEvent
import asyncio


async def stream_text():
options = ClaudeAgentOptions(include_partial_messages=True)

async for message in query(prompt="Explain how databases work", options=options):
if isinstance(message, StreamEvent):
event = message.event
if event.get("type") == "content_block_delta":
delta = event.get("delta", {})
if delta.get("type") == "text_delta":
# Print each text chunk as it arrives
print(delta.get("text", ""), end="", flush=True)

print()  # Final newline


asyncio.run(stream_text())

串流工具呼叫

工具呼叫也會增量串流。您可以追蹤工具何時開始、在生成時接收其輸入,以及查看何時完成。下面的範例追蹤目前被呼叫的工具並在串流進來時累積 JSON 輸入。它使用三種事件類型:

  • content_block_start:工具開始
  • content_block_delta 搭配 input_json_delta:輸入區塊到達
  • content_block_stop:工具呼叫完成
from claude_agent_sdk import query, ClaudeAgentOptions
from claude_agent_sdk.types import StreamEvent
import asyncio


async def stream_tool_calls():
options = ClaudeAgentOptions(
include_partial_messages=True,
allowed_tools=["Read", "Bash"],
)

# Track the current tool and accumulate its input JSON
current_tool = None
tool_input = ""

async for message in query(prompt="Read the README.md file", options=options):
if isinstance(message, StreamEvent):
event = message.event
event_type = event.get("type")

if event_type == "content_block_start":
# New tool call is starting
content_block = event.get("content_block", {})
if content_block.get("type") == "tool_use":
current_tool = content_block.get("name")
tool_input = ""
print(f"Starting tool: {current_tool}")

elif event_type == "content_block_delta":
delta = event.get("delta", {})
if delta.get("type") == "input_json_delta":
# Accumulate JSON input as it streams in
chunk = delta.get("partial_json", "")
tool_input += chunk
print(f"  Input chunk: {chunk}")

elif event_type == "content_block_stop":
# Tool call complete - show final input
if current_tool:
print(f"Tool {current_tool} called with: {tool_input}")
current_tool = None


asyncio.run(stream_tool_calls())

建立串流 UI

此範例將文字和工具串流結合成一個有凝聚力的 UI。它追蹤代理目前是否正在執行工具(使用 in_tool 旗標)以顯示狀態指示器,例如在工具執行時顯示 [Using Read...]。文字在不在工具中時正常串流,工具完成會觸發「完成」訊息。此模式對於需要在多步驟代理任務期間顯示進度的聊天介面很有用。

from claude_agent_sdk import query, ClaudeAgentOptions, ResultMessage
from claude_agent_sdk.types import StreamEvent
import asyncio
import sys


async def streaming_ui():
options = ClaudeAgentOptions(
include_partial_messages=True,
allowed_tools=["Read", "Bash", "Grep"],
)

# Track whether we're currently in a tool call
in_tool = False

async for message in query(
prompt="Find all TODO comments in the codebase", options=options
):
if isinstance(message, StreamEvent):
event = message.event
event_type = event.get("type")

if event_type == "content_block_start":
content_block = event.get("content_block", {})
if content_block.get("type") == "tool_use":
# Tool call is starting - show status indicator
tool_name = content_block.get("name")
print(f"\n[Using {tool_name}...]", end="", flush=True)
in_tool = True

elif event_type == "content_block_delta":
delta = event.get("delta", {})
# Only stream text when not executing a tool
if delta.get("type") == "text_delta" and not in_tool:
sys.stdout.write(delta.get("text", ""))
sys.stdout.flush()

elif event_type == "content_block_stop":
if in_tool:
# Tool call finished
print(" done", flush=True)
in_tool = False

elif isinstance(message, ResultMessage):
# Agent finished all work
print(f"\n\n--- Complete ---")


asyncio.run(streaming_ui())

已知限制

  • 結構化輸出:JSON 結果僅出現在最終 ResultMessage.structured_output 中,而不是作為串流增量。如需詳細資訊,請參閱結構化輸出

後續步驟

現在您可以即時串流文字和工具呼叫,請探索這些相關主題: