Sync ACP¶

Sync ACP provides the simplest way to build agents in Agentex. Perfect for blocking request/response interactions (like chat bots) where you don't need complex state management or workflow control.

Core Characteristics¶

Single handler method: @acp.on_message_send
Automatic task lifecycle management - Tasks created and managed automatically
Direct message processing - Respond to messages immediately
Automatic message management - Agentex Server creates messages on your behalf
Minimal complexity - Focus on your business logic

Message Flow¶

sequenceDiagram
    participant Client
    participant Agentex
    participant Agent

    Client->>Agentex: Send Message
    Agentex->>Agentex: Auto-create Task
    Agentex->>Agent: on_message_send(params)
    Agent->>Agent: Process Message
    Agent-->>Agentex: Return Response
    Agentex-->>Client: Response
    Note over Agentex: Task remains open for future messages

Basic Implementation¶

from agentex.lib.sdk.fastacp.fastacp import FastACP
from agentex.lib.types.acp import SendMessageParams
from agentex.types.text_content import TextContent
from agentex.types.message_author import MessageAuthor

# Create Sync ACP server
acp = FastACP.create(acp_type="sync")

@acp.on_message_send
async def handle_message(params: SendMessageParams):
    """Process incoming messages and return responses"""

    # Access the user's message
    user_message = params.content.content

    # Process and create response
    response_text = f"You said: {user_message}"

    # Return response (Agentex auto-creates the message)
    return TextContent(
        author=MessageAuthor.AGENT,
        content=response_text
    )

Handler Parameters¶

SendMessageParams¶

The @acp.on_message_send handler receives:

Bases: BaseModel

Parameters for message/send method.

Attributes:

Name	Type	Description
`agent`	`Agent`	The agent that the message was sent to.
`task`	`Task`	The task that the message was sent to.
`content`	`TaskMessageContent`	The message that was sent to the agent.
`stream`	`bool`	Whether to stream the message back to the agentex server from the agent.
`request`	`dict[str, Any] \| None`	Additional request context including headers forwarded to this agent.