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Install the SDK, write your first agent, and test it — locally or deployed to the cloud.

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Prerequisites

OpenAI API Key required. Set it as an environment variable before running your agent:
export OPENAI_API_KEY="your-key-here"

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Installation

pip install smallestai

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Write Your First Agent

Create two files: one for the agent logic, and one to run the application.
1

Create my_agent.py

Subclass OutputAgentNode and implement generate_response() to stream LLM output.
my_agent.py
import os
from smallestai.atoms.agent.nodes import OutputAgentNode
from smallestai.atoms.agent.clients.openai import OpenAIClient

class MyAgent(OutputAgentNode):
    def __init__(self):
        super().__init__(name="my-agent")
        self.llm = OpenAIClient(
            model="gpt-4o-mini",
            api_key=os.getenv("OPENAI_API_KEY")
        )

    async def generate_response(self):
        response = await self.llm.chat(
            messages=self.context.messages,
            stream=True
        )
        async for chunk in response:
            if chunk.content:
                yield chunk.content
2

Create main.py

Wire up AtomsApp with a setup_handler that adds your agent to the session.
main.py
from smallestai.atoms.agent.server import AtomsApp
from smallestai.atoms.agent.session import AgentSession
from my_agent import MyAgent

async def on_start(session: AgentSession):
    session.add_node(MyAgent())
    await session.start()
    await session.wait_until_complete()

if __name__ == "__main__":
    app = AtomsApp(setup_handler=on_start)
    app.run()
Your entry point can be named anything (app.py, run.py, etc.). When deploying, specify it with --entry-point your_file.py.
Want a greeting? Use @session.on_event to speak when the user joins:
@session.on_event("on_event_received")
async def on_event(_, event):
    if isinstance(event, SDKSystemUserJoinedEvent):
        agent.context.add_message({"role": "assistant", "content": "Hello!"})
        await agent.speak("Hello! How can I help?")
Adding the greeting to context ensures the LLM knows the conversation has started.

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Run Your Agent

Once your files are ready, you have two options:
For development and testing, run the file directly:
python main.py
This starts a WebSocket server on localhost:8080. In a separate terminal, connect to it:
smallestai agent chat
No account or deployment needed.

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What’s Next?

Tool Calling

Give your agent calculators, search, and APIs.

Orchestration

Connect multiple agents for complex workflows.

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Need Help?

Join Discord

Ask questions, share what you’re building, and get help from other developers.