Strands Agents SDK マルチエージェント — マルチエージェントパターンの選び方

@tool
def summarizer(text: str) -> str:
    """Summarize the given text into 2 concise sentences.
 
    Args:
        text: The text to summarize
 
    Returns:
        A concise summary
    """
    agent = Agent(model=bedrock_model, system_prompt="Summarize in exactly 2 sentences.", callback_handler=None)
    return agent(f"Summarize this: {text}").message['content'][0]['text']
 
@tool
def translator(text: str, target_language: str) -> str:
    """Translate the given text into the specified language.
 
    Args:
        text: The text to translate
        target_language: The target language
 
    Returns:
        The translated text
    """
    agent = Agent(model=bedrock_model, system_prompt="Translate accurately. Return only the translation.", callback_handler=None)
    return agent(f"Translate into {target_language}: {text}").message['content'][0]['text']

from strands import Agent, tool
from strands.models import BedrockModel
from strands.multiagent import Swarm, GraphBuilder
 
bedrock_model = BedrockModel(
    model_id="us.anthropic.claude-sonnet-4-20250514-v1:0",
    region_name="us-east-1",
)
 
TASK = "Summarize what Amazon Bedrock is in 2 sentences, then translate the summary into Japanese."
 
# Pattern A: Agents as Tools
@tool
def summarizer(text: str) -> str:
    """Summarize the given text into 2 concise sentences.
 
    Args:
        text: The text to summarize
 
    Returns:
        A concise summary
    """
    agent = Agent(model=bedrock_model, system_prompt="Summarize in exactly 2 sentences.", callback_handler=None)
    return agent(f"Summarize this: {text}").message['content'][0]['text']
 
@tool
def translator(text: str, target_language: str) -> str:
    """Translate the given text into the specified language.
 
    Args:
        text: The text to translate
        target_language: The target language
 
    Returns:
        The translated text
    """
    agent = Agent(model=bedrock_model, system_prompt="Translate accurately. Return only the translation.", callback_handler=None)
    return agent(f"Translate into {target_language}: {text}").message['content'][0]['text']
 
orchestrator = Agent(
    model=bedrock_model, tools=[summarizer, translator],
    system_prompt="First summarize, then translate to Japanese.",
    callback_handler=None,
)
result_a = orchestrator(TASK)
summary_a = result_a.metrics.get_summary()
print(f"Agents as Tools: {summary_a['total_cycles']} cycles, {summary_a['total_duration']:.1f}s, {summary_a['accumulated_usage']['totalTokens']} tokens")
 
# Pattern B: Swarm
summarizer_agent = Agent(name="summarizer", model=bedrock_model, system_prompt="Summarize the topic in exactly 2 sentences, then hand off to the translator.", callback_handler=None)
translator_agent = Agent(name="translator", model=bedrock_model, system_prompt="Translate the provided summary into Japanese. Do not hand off.", callback_handler=None)
swarm = Swarm([summarizer_agent, translator_agent], entry_point=summarizer_agent, max_handoffs=5, max_iterations=5)
result_b = swarm(TASK)
print(f"Swarm: {result_b.execution_count} nodes, {result_b.execution_time}ms")
 
# Pattern C: Graph
summarizer_agent2 = Agent(name="summarizer2", model=bedrock_model, system_prompt="Summarize the topic in exactly 2 sentences.", callback_handler=None)
translator_agent2 = Agent(name="translator2", model=bedrock_model, system_prompt="Translate the provided text into Japanese.", callback_handler=None)
builder = GraphBuilder()
builder.add_node(summarizer_agent2, "summarize")
builder.add_node(translator_agent2, "translate")
builder.add_edge("summarize", "translate")
builder.set_entry_point("summarize")
graph = builder.build()
result_c = graph(TASK)
total_time_c = sum(nr.execution_time for nr in result_c.results.values())
print(f"Graph: {len(result_c.execution_order)} nodes, {total_time_c}ms")