Pipeline

For multi-agent orchestration, AgentScope provides the agentscope.pipeline module as syntax sugar for chaining agents together, including

• MsgHub: a message hub for broadcasting messages among multiple agents

• sequential_pipeline and SequentialPipeline: a functional and class-based implementation that chains agents in a sequential manner

import os, asyncio

from agentscope.formatter import DashScopeMultiAgentFormatter
from agentscope.message import Msg
from agentscope.model import DashScopeChatModel
from agentscope.agent import ReActAgent
from agentscope.pipeline import MsgHub

Broadcasting with MsgHub

The MsgHub class is an async context manager, receiving a list of agents as its participants. When one participant generates a replying message, all other participants will receive this message by calling their observe method.

That means within a MsgHub context, developers don’t need to manually send a replying message from one agent to another. The broadcasting is automatically handled.

Here we create four agents: Alice, Bob, Charlie and David. Then we start a meeting with Alice, Bob and Charlie by introducing themselves. Note David is not included in this meeting.

def create_agent(name: str, age: int, career: str) -> ReActAgent:
    """Create agent object by the given information."""
    return ReActAgent(
        name=name,
        sys_prompt=f"You're {name}, a {age}-year-old {career}",
        model=DashScopeChatModel(
            model_name="qwen-max",
            api_key=os.environ["DASHSCOPE_API_KEY"],
        ),
        formatter=DashScopeMultiAgentFormatter(),
    )


alice = create_agent("Alice", 50, "teacher")
bob = create_agent("Bob", 35, "engineer")
charlie = create_agent("Charlie", 28, "designer")
david = create_agent("David", 30, "developer")

Then we start a meeting and let them introduce themselves without manual message passing:

Hint

The message in announcement will be broadcasted to all participants when entering the MsgHub context.

async def example_broadcast_message():
    """Example of broadcasting messages with MsgHub."""

    # Create a message hub
    async with MsgHub(
        participants=[alice, bob, charlie],
        announcement=Msg(
            "user",
            "Now introduce yourself in one sentence, including your name, age and career.",
            "user",
        ),
    ) as hub:
        # Group chat without manual message passing
        await alice()
        await bob()
        await charlie()


asyncio.run(example_broadcast_message())

Alice: Hello, I'm Alice, a 50-year-old teacher with a passion for helping students learn and grow.
Bob: Hello, I'm Bob, a 35-year-old engineer with a focus on innovative solutions and problem-solving.
Charlie: Hello, I'm Charlie, a 28-year-old designer with a flair for creating visually appealing and functional designs.

Now let’s check if Bob, Charlie and David received Alice’s message.

async def check_broadcast_message():
    """Check if the messages are broadcasted correctly."""
    user_msg = Msg(
        "user",
        "Do you know who's Alice, and what she does? Answer me briefly.",
        "user",
    )

    await bob(user_msg)
    await charlie(user_msg)
    await david(user_msg)


asyncio.run(check_broadcast_message())

Bob: Alice is a 50-year-old teacher who is passionate about helping students learn and grow.
Charlie: Alice is a 50-year-old teacher who is passionate about helping students learn and grow.
David: I don't have specific information about an Alice you're referring to, as there could be many people with that name. Could you provide more details, such as a last name or the context in which you encountered Alice?

Now we observe that Bob and Charlie know Alice and her profession, while David has no idea about Alice since he is not included in the MsgHub context.

Dynamic Participant Management

Additionally, MsgHub supports to dynamically manage participants by the following methods:

• add: add one or multiple agents as new participants

• delete: remove one or multiple agents from participants, and they will no longer receive broadcasted messages

• broadcast: broadcast a message to all current participants

Note

The newly added participants will not receive the previous messages.

async with MsgHub(participants=[alice]) as hub:
    # Add new participants
    hub.add(david)

    # Remove participants
    hub.delete(alice)

    # Broadcast to all current participants
    await hub.broadcast(
        Msg("system", "Now we begin to ...", "system"),
    )

Pipeline

Pipeline serves as a syntax sugar for multi-agent orchestration.

Currently, AgentScope provides a sequential pipeline implementation, which execute agents one by one in a predefined order. For example, the two following code snippets are equivalent:

Code snippet 1: Manually call agents one by one

msg = None
msg = await alice(msg)
msg = await bob(msg)
msg = await charlie(msg)
msg = await david(msg)

Code snippet 2: Use sequential pipeline

from agentscope.pipeline import sequential_pipeline
msg = await sequential_pipeline(
    # List of agents to be executed in order
    agents=[alice, bob, charlie, david],
    # The first input message, can be None
    msg=None
)

Tip

By combining MsgHub and sequential_pipeline, you can create more complex workflows very easily.

Additionally, for reusability, we also provide a class-based implementation:

Using SequentialPipeline class

from agentscope.pipeline import SequentialPipeline

# Create a pipeline object
pipeline = SequentialPipeline(agents=[alice, bob, charlie, david])

# Call the pipeline
msg = await pipeline(msg=None)

# Reuse the pipeline with different input
msg = await pipeline(msg=Msg("user", "Hello!", "user"))