> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# As Step Hook • AI Agent SDK
> as_step_hook: Adapt a plain ``on_step`` callback into an ``after_model`` middleware hook.
# as\_step\_hook
Function
> This function is defined in the [**middleware**](../modules/middleware) module.
Adapt a plain `on_step` callback into an `after_model` middleware hook.
`HooksConfig(on_step=...)` advertises "called once per agent step". An
agent step is one model call, so the callback is routed onto the existing
`after_model` middleware slot: it is invoked with the :class:`ModelResponse`
for the step and its return value is ignored (the response passes through
unchanged, so an observer can never corrupt the run).
```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
%%{init: {'theme': 'base', 'themeVariables': { 'primaryColor': '#8B0000', 'primaryTextColor': '#fff', 'primaryBorderColor': '#710101', 'lineColor': '#189AB4', 'secondaryColor': '#189AB4', 'tertiaryColor': '#fff' }}}%%
graph TD
event["Event Trigger"] --> hook["Hook: as_step_hook"]
hook --> decision{"Decision"}
decision -- "Allow" --> proc["Process"]
decision -- "Deny" --> block["Block"]
style hook fill:#189AB4,color:#fff
style event fill:#8B0000,color:#fff
style proc fill:#8B0000,color:#fff
style block fill:#8B0000,color:#fff
```
## Signature
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
def as_step_hook(callback: Callable[[Any], Any]) -> AfterModelFn
```
## Parameters
No description available.
### Returns
The result of the operation.
## Source
`praisonaiagents/hooks/middleware.py` at line 318
***
## Related Documentation