FIFTY AGENT SDK

# imports omitted; weather data is a fixed fixture
@tool()
async def get_weather(city: str) -> dict[str, Any]:
    """Return the current weather for a city."""
    return {"city": city, "temp_c": 21}

registry = Registry()
InProcProvider([get_weather]).register_into(registry)

# imports and configured llm/registry omitted
loop = AgentLoop(
    llm=llm,
    registry=registry,
    parser=JsonModeParser(),
    prompts=PromptSections(persona="You are helpful."),
    safety=SafetyConfig(),
    model="gpt-4o",
    output_format=JSON_MODE_OUTPUT_FORMAT,
)
runner = AgentRunner(
    loop=loop,
    state=MemoryStateStore(),
    system_prompt="You are a helpful weather assistant.",
)

# inside async setup, using the runner above
async for event in runner.run(
    "session-1", "What's the weather in Paris?"
):
    if event.event_type == "tool_failed":
        print(event.error)
    elif event.event_type == "final":
        print(event.text)

# existing loop and session_id with at least four messages
store = runner.state
branch = await store.fork(session_id, from_sequence=4)
await store.switch_branch(session_id, branch)
await store.append(
    session_id, ChatMessage(role="user", content="...edited...")
)
await store.get_messages(session_id, branch_id="trunk")