AgentScope Multi-Agent Pipelines — MsgHub + FanoutPipeline

Pattern 1: SequentialPipeline (serial)
A → B → C → result

Pattern 2: FanoutPipeline (parallel)
    ┌→ B ─┐
A → ├→ C ─┤ → aggregate
    └→ D ─┘

Pattern 3: MsgHub (group chat)
A ←→ B ←→ C (everyone sees all messages)

from agentscope.agent import ReActAgent
from agentscope.model import OpenAIChatModel
from agentscope.memory import InMemoryMemory
from agentscope.formatter import OpenAIChatFormatter
from agentscope.pipeline import SequentialPipeline
import os, asyncio

model = OpenAIChatModel(
    model_name="gpt-4o",
    api_key=os.environ["OPENAI_API_KEY"],
    stream=True,
)

researcher = ReActAgent(
    name="Researcher",
    sys_prompt="You are a research specialist. Given a topic, produce detailed research notes with key facts, statistics, and insights.",
    model=model,
    memory=InMemoryMemory(),
    formatter=OpenAIChatFormatter(),
)

analyst = ReActAgent(
    name="Analyst",
    sys_prompt="You are a data analyst. Take research notes and extract actionable insights, patterns, and recommendations.",
    model=model,
    memory=InMemoryMemory(),
    formatter=OpenAIChatFormatter(),
)

writer = ReActAgent(
    name="Writer",
    sys_prompt="You are a technical writer. Take analysis results and write a clear, well-structured report for a non-technical audience.",
    model=model,
    memory=InMemoryMemory(),
    formatter=OpenAIChatFormatter(),
)

pipeline = SequentialPipeline([researcher, analyst, writer])