> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trycurious.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Every decision returns the control

> Why decide keeps serving the control: initializing, variants awaiting approval, every variant concluded, the holdout, sticky assignment, or a restart.

Decisions come back with `arm_type: "control"` every time. One of these is the cause; check them in order.

## The experiment is still initializing

`experiment_status` is `initializing`. Curious is generating the first variants and building the model, and serves the control meanwhile. This takes minutes, not seconds, after the first declaration. Nothing to do; the status moves to `exploring` when variants are live. See [The experiment lifecycle](https://docs.trycurious.ai/concepts/lifecycle.md).

## Variants are waiting for approval

`experiment_status` is still `initializing` long after the declaration, and the dashboard shows variants marked pending. `options.approval` defaults to `manual`, so generated variants wait for a person. Approve them in the [dashboard](https://app.trycurious.ai), or declare `"options": { "approval": "auto" }`. See [Approval](https://docs.trycurious.ai/concepts/approval.md).

## Every variant was concluded

The response carries a warning:

```json theme={null}
"warnings": [{ "code": "serving_control_only", "message": "Every variant is concluded. The control is serving alone until new variants are generated." }]
```

The variants lost, proved equivalent, or breached a constraint, and the next generation round has not landed yet. Read their conclusions in the dashboard; if a constraint is concluding everything, its threshold may be mis-declared. See [Constraints](https://docs.trycurious.ai/concepts/constraints.md).

## This user is in the holdout

Some users always see the control by design: the share is `options.holdout`, five percent by default, chosen deterministically per user and element. Try a different `user_id`. See [Assignment and stickiness](https://docs.trycurious.ai/concepts/assignment.md#the-holdout-cohort).

## This user is sticky to the control

Under `options.assignment: "static"`, a user who was first served the control keeps it while the control is live, which is always. Try a different `user_id`, or compare across many users rather than one.

## The experiment just restarted

A declaration-class field changed, the experiment was superseded, and the successor is `initializing` with only the control. See [The experiment restarted](https://docs.trycurious.ai/troubleshooting/experiment-restarted.md).

## Still the control?

Look at the element in the dashboard: its status, its arms and their states. Quote the `X-Request-Id` of a decision to [support](mailto:team@trycurious.ai).


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