class MessageEvent(BaseModel):
    event_type: MessageEventType = Field(default=MessageEventType.alpha)
    output: str


class MessageOutput(BaseModel):
    body: str = ""
    events: list[MessageEvent] = []


class Message(BaseModel):
    input: str
    output: MessageOutput


app = FastAPI(title="Minimal FastAPI App", version="1.0.0")


@app.post("/messages", response_model=Message)