Router Steps

Parameters

Parameter	Type	Default	Description
`selector`	`Callable[[StepInput], ...] \| Callable[[StepInput, list], ...] \| str`	`None`	Function or CEL expression string to select steps dynamically. Functions can optionally accept `step_choices` as second parameter
`choices`	`WorkflowSteps`	Required	Available steps for selection. Supports nested lists (becomes Steps container)
`name`	`Optional[str]`	`None`	Name of the router step
`description`	`Optional[str]`	`None`	Description of the router step
`human_review`	`Optional[HumanReview]`	`None`	All HITL settings in a single config. See HumanReview Config.
`requires_confirmation`	`bool`	`False`	Pause for user confirmation before executing selected route
`confirmation_message`	`Optional[str]`	`None`	Message shown to user when requesting confirmation
`requires_user_input`	`bool`	`False`	Pause for user to select route(s) instead of using selector. See Router HITL.
`user_input_message`	`Optional[str]`	`None`	Message shown to user when requesting route selection
`allow_multiple_selections`	`bool`	`False`	Allow user to select multiple routes
`user_input_schema`	`Optional[List[Dict[str, Any]]]`	`None`	Custom input schema for the user-input pause. If unset, the pause presents the available `choices` for route selection
`requires_output_review`	`bool`	`False`	Pause after the selected route completes to review its output. See Output Review.
`output_review_message`	`Optional[str]`	`None`	Message shown to user during output review
`hitl_max_retries`	`int`	`3`	Max re-executions when an output review is rejected with `OnReject.retry`
`on_reject`	`Union[OnReject, str]`	`OnReject.skip`	Action when rejected: `skip`, `cancel`, `retry`

Selector Return Types

The selector function can return any of the following:

Return Type	Description
`str`	Step name as string - Router resolves it from choices
`Step`	Step object directly
`List[Step]`	List of steps for chaining execution

selector also accepts a CEL expression string in place of a function. The expression must evaluate to a step name from choices.

Selector Function Signatures

Basic Signature

def selector(step_input: StepInput) -> Union[str, Step, List[Step]]:
    ...

Extended Signature (with step_choices)

def selector(step_input: StepInput, step_choices: list) -> Union[str, Step, List[Step]]:
    ...

The step_choices parameter provides access to the prepared Step objects from Router.choices, enabling dynamic selection based on available options.

Extended Signature (with session_state)

def selector(step_input: StepInput, session_state: dict) -> Union[str, Step, List[Step]]:
    ...

If the selector accepts a session_state parameter, the workflow’s session state is passed to it at call time.

Async Support

All selector signatures support async functions:

async def selector(step_input: StepInput, step_choices: list) -> Union[str, Step, List[Step]]:
    ...

Agno SDK Reference

AgentOS API Reference

Agno CLI

Agno Infra CLI

Router Steps

Parameters

Selector Return Types

Selector Function Signatures

Basic Signature

Extended Signature (with step_choices)

Extended Signature (with session_state)

Async Support

​Parameters

​Selector Return Types

​Selector Function Signatures

​Basic Signature

​Extended Signature (with step_choices)

​Extended Signature (with session_state)

​Async Support

Parameters

Selector Return Types

Selector Function Signatures

Basic Signature

Extended Signature (with step_choices)

Extended Signature (with session_state)

Async Support