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

# MODEL PLAYGROUND

The **Model Playground** puts several models side by side in their own chat panels and sends one prompt to all of them at once. It answers "which model is better for my task?"
You can compare a deployed fine-tuned model to a base model, an open-source model to a frontier model, or any combination you choose.

The Oumi Agent can tell you which of your deployments are available to compare and point you here, but it cannot drive the Playground for you. You open the page and run the comparison yourself.

***

## WHEN TO USE THE PLAYGROUND

Check out the Playground when the question is qualitative and you want an answer in seconds. The Playground can also help you answer questions about latency, token effiency, and cost on a per-request basis.

| Use the Playground                                     | Use an [evaluation](/guides/evaluations)      |
| ------------------------------------------------------ | --------------------------------------------- |
| "Does the fine-tune sound better than the base model?" | "Which model scores higher, and by how much?" |
| A handful of prompts you type by hand                  | A dataset of many examples                    |
| Reading answers yourself                               | Metrics, scores, or a judge                   |
| Instant, throwaway                                     | Repeatable and recorded                       |

A Playground session is a good sanity check before you invest in a full evaluation. It is not a substitute for one: nothing you do here is scored, saved, or reproducible.

## OPEN THE PLAYGROUND

Select **Playground** in the project sidebar. The page opens empty, with a prompt to select models. In the Playground, you can chat with any of your existing [Deployments](/guides/deployment) or with an open-source base model.
If you have a deployment with an [external model](/guides/deployment/deploy-a-model#before-you-start), you will have the opportunity to directly compare a frontier lab's model to your own.

***

## ADD MODELS TO COMPARE

Click `Add Model...` to open a searchable picker with two groups:

* **Your deployments.** Every deployment in the project that has not been deleted. A deployment must be `Active` before you can chat with it. You can add one that is still starting up, but its panel stays disabled and shows the current status until it becomes active.
* **Oumi base models.** Untrained open-source models that Oumi serves directly, ready to chat with no deployment of your own. This group appears only where Oumi is serving base models for your project.

Each pick opens another panel, up to **four panels at once**. `Add Model...` is disabled once you reach four.

<Tip>You can chat with more than one copy of the same deployment or base model. Two panels running the same deployment let you compare two system prompts or two temperature settings against each other. Repeat panels are numbered in the header, so the second copy reads `My Deployment #2`.</Tip>

***

## SEND A PROMPT

Type in the input at the bottom of the page and press `Enter`, or click the arrow. The prompt goes to every ready panel at the same time, and each panel streams its own answer independently.

Panels keep separate conversations. Follow-up prompts also fan out to all of them, so each model sees only its own history.

While any panel is still generating:

* The send button becomes a **stop** button that stops every panel at once.
* Each streaming panel gets its own stop button in its header, to stop just that one.

Stopping keeps whatever text had already streamed in, including a partial response. Keep in mind that all of these conversations are ephemeral, so navigating away from the page will lose them. The "Playground" feature is designed for quick experiments
where you may want to compare performance or cost of different models or configurations.

<Warning>Leaving the page while a response is still generating loses the in-flight answers. Your browser warns you first.</Warning>

***

## SWITCH A PANEL'S MODEL

Click the model name in a panel header to swap that panel to a different model in place. This is the fastest way to ask "what would a different model have said?" without retyping the conversation.

When you switch:

* The conversation stays, and the new model picks it up from there.
* The panel's system prompt follows it across.
* The panel's sampling parameters reset, because the new model may accept a different set.
* Your next message is marked with a `Model changed to ...` divider, so the transcript shows exactly where the answers stopped coming from the old model.

## WHAT'S NEXT

<CardGroup cols={1}>
  <Card title="System prompts and sampling parameters" icon="gear" href="/guides/playground/system-prompts-and-parameters">
    Learn how to use system prompts and sampling parameters to tune the behavior of the models.
  </Card>
</CardGroup>