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# set_history

> Control what the model still sees from earlier steps when this step is entered.

[ref-step]: /docs/server-sdks/reference/python/agents/context-builder/step

[ref-context-set-history]: /docs/server-sdks/reference/python/agents/context-builder/context/set-history

Control what the model still sees when this step is entered. The mode applies at
the moment of entry and governs everything that came before, including the turn
that triggered the transition. It doesn't affect this step's own turns, which
accumulate fresh. Nothing is deleted: the call log keeps every message.

Overrides the context-level default set with
[`Context.set_history()`][ref-context-set-history].

## Parameters

**`history`** `str` — required

One of three modes.

* `"keep"` -- clear nothing. Every prior step's instructions and dialogue stay
  visible to the model.
* `"default"` -- hide the prior step instructions, keep the user and assistant
  dialogue. This is the behavior when unset.
* `"hide"` -- hide the prior instructions and pull the prior dialogue out of the
  model's context. Pair it with a `${step_history.*}` reference in this step's
  text to choose exactly what comes back.

---

## Returns

[`Step`][ref-step] -- Self for method chaining.

## Raises

`ValueError` if `history` is not one of the three modes.

## Example

```python {8-10}
from signalwire import AgentBase

agent = AgentBase(name="my-agent", route="/agent")

contexts = agent.define_contexts()
ctx = contexts.add_context("default")
ctx.add_step("collect_trip").set_text("Ask where the caller is going and when.")
ctx.add_step("confirm_trip").set_history("hide").set_text(
    "Previously: ${step_history.prev.summary}\n\nConfirm the booking details."
)

agent.serve()
```

> Control what the model still sees from earlier steps when this step is entered.