@observe

def observe(
    name: str | None = None,
    *,
    tags: list[str] | None = None,
    metadata: dict | None = None,
    user_id: str | Callable[[], str | None] | None = None,
    session_id: str | Callable[[], str | None] | None = None,
    version: str | None = None,
    trace_id: str | Callable[[], str | None] | None = None,
    capture_input: bool = False,
    capture_output: bool = False,
) -> Callable

from rdk import observe

@observe()
def chat(message: str) -> str:
    # trace name defaults to "chat"
    ...

@observe(name="customer-support")
def handle_request(message: str) -> str:
    ...

from rdk import observe

@observe(
    name="chat-pipeline",
    tags=["production", "claude"],
    metadata={"team": "ml-platform"},
    version="2.1.0",
)
def pipeline(question: str) -> str:
    ...

from rdk import observe

@observe(
    name="chat",
    user_id=lambda: get_current_user_id(),    # Callable — evaluated at call time
    session_id=lambda: get_session_id(),
)
def chat(message: str) -> str:
    ...

from rdk import observe

@observe(name="summarize", capture_input=True, capture_output=True)
def summarize(text: str) -> str:
    # Arguments stored in trace.metadata["input"]
    # Return value stored in trace.metadata["output"]
    ...

from rdk import observe

@observe(name="sync-chat")
def sync_chat(message: str) -> str:
    ...

@observe(name="async-chat")
async def async_chat(message: str) -> str:
    ...

@observe(name="outer")
def outer():
    inner()  # No new trace created; spans go to "outer"

@observe(name="inner")
def inner():
    ...

from rdk import trace

with trace("my-operation", tags=["dev"]) as t:
    print(f"Trace ID: {t.id}")
    # LLM calls here are captured