microsoft/autogen · error · RuntimeError

InputRequestContext.runtime() must be called within the inpu

Error message

InputRequestContext.runtime() must be called within the input callback of a UserProxyAgent.

What it means

InputRequestContext.request_id() reads a ContextVar that is only set while UserProxyAgent is inside its input callback (via populate_context). Calling it outside that dynamic scope raises a LookupError wrapped in this RuntimeError, because there is no active input request to identify.

Source

Thrown at python/packages/autogen-agentchat/src/autogen_agentchat/agents/_user_proxy_agent.py:156

        _INPUT_REQUEST_CONTEXT_VAR: ClassVar[ContextVar[str]] = ContextVar("_INPUT_REQUEST_CONTEXT_VAR")

        @classmethod
        @contextmanager
        def populate_context(cls, ctx: str) -> Generator[None, Any, None]:
            """:meta private:"""
            token = UserProxyAgent.InputRequestContext._INPUT_REQUEST_CONTEXT_VAR.set(ctx)
            try:
                yield
            finally:
                UserProxyAgent.InputRequestContext._INPUT_REQUEST_CONTEXT_VAR.reset(token)

        @classmethod
        def request_id(cls) -> str:
            try:
                return cls._INPUT_REQUEST_CONTEXT_VAR.get()
            except LookupError as e:
                raise RuntimeError(
                    "InputRequestContext.runtime() must be called within the input callback of a UserProxyAgent."
                ) from e

    def __init__(
        self,
        name: str,
        *,
        description: str = "A human user",
        input_func: Optional[InputFuncType] = None,
    ) -> None:
        """Initialize the UserProxyAgent."""
        super().__init__(name=name, description=description)
        self.input_func = input_func or cancellable_input
        self._is_async = iscoroutinefunction(self.input_func)

    @property
    def produced_message_types(self) -> Sequence[type[BaseChatMessage]]:
        """Message types this agent can produce."""

View on GitHub (pinned to 027ecf0a37)

Solutions

Move the request_id() call inside the input_func callback passed to UserProxyAgent, or inside a populate_context block.
Pass the request id explicitly to components that run outside the callback instead of reading the context var.
Guard usage with try/except RuntimeError and treat it as 'no active input request'.

Example fix

// before
rid = UserProxyAgent.InputRequestContext.request_id()  # outside callback -> raises

// after
async def my_input(prompt: str, ct: CancellationToken | None) -> str:
    rid = UserProxyAgent.InputRequestContext.request_id()  # inside callback: ok
    return await ui.get_input(rid, prompt)

Defensive patterns

Strategy: try-catch

Validate before calling

# Read the id only inside the callback
async def input_func(prompt: str, ct) -> str:
    try:
        rid = UserProxyAgent.InputRequestContext.request_id()
    except RuntimeError:
        rid = "unavailable"
    return await ui.get_input(rid, prompt)

Try / catch

try:
    rid = UserProxyAgent.InputRequestContext.request_id()
except RuntimeError as e:
    if "must be called within the input callback" in str(e):
        rid = None  # no active input request; use a fallback identifier
    else:
        raise

Prevention

Call request_id() only within input_func or a populate_context block.
Pass the request id explicitly to out-of-band UI components instead of reading the ContextVar.

When it happens

Trigger: Calling InputRequestContext.request_id() (or a helper that uses it, e.g. runtime UI bindings) from arbitrary code outside the input_func callback, or before the agent has requested input.

Common situations: UI integrations (e.g. web frontends) that fetch the runtime request id eagerly at startup or in background tasks instead of inside the input callback thread/task that UserProxyAgent invoked.

Related errors

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/642ece3b05ac8c8d. Report an issue: GitHub.