---
title: "Test in the Playground"
description: "Chat with a running Model Endpoint in the Playground and change its output length, temperature, top-p, top-k, and repetition penalty in the portal."
content_type: "how-to"
product: "model-endpoints"
platform: "TIR"
url: "/tir/model-endpoints/how-to/test-in-the-playground/"
topic: ["call"]
---

# Test in the Playground

Chat with your endpoint in the portal to see how the model answers, before you connect an application. The Playground is a chat window for an endpoint that serves chat models.

## Before you begin

- An endpoint on vLLM or another framework of the vLLM family, in the **Running**, **Idle**, or **Partially Available** state.
- Permission to read model endpoints in the project. A Member needs a policy that grants read permission for the Inference service.
- An instruct or chat model. To test any other model, use your own client or the sample requests; see [Call an endpoint with a token](/tir/model-endpoints/how-to/call-an-endpoint-with-a-token/).

## Open the Playground

In the **Model Endpoints** list, select **Playground** on the endpoint's row. You can also select **Playground** on the endpoint's details page. The chat opens with that endpoint selected. **Playground** is also its own entry in the side menu, under **Inference**.

## Set the generation options

Five sliders shape the answer. Set them before you send a prompt; the defaults suit a first try.

| Option                 | Range     | Starts at | What it changes                                                                                                                                    |
| ---------------------- | --------- | --------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Output Length**      | 1 to 1024 | 512       | The most tokens in the answer. A higher value allows a longer answer, which takes longer to write.                                                 |
| **Temperature**        | 0 to 2    | 0.5       | How random the answer is. Around 0.1 to 0.3 gives steady, repeatable answers; around 0.7 to 1.0 gives more varied ones.                            |
| **Top-P**              | 0 to 1    | 1         | Limits each word to the most likely choices whose chances add up to this share, such as 0.9. A lower value gives more focused text.                |
| **Top-K**              | 1 to 100  | 1         | Limits each word to this many of the most likely choices. A small value keeps the text focused, and a larger one, such as 50, allows more variety. |
| **Repetition Penalty** | 0 to 2    | 0         | Discourages words that already appeared. A higher value pushes the model harder to avoid repeating itself.                                         |

## Check the answer

Type a prompt in the chat, and the model's reply appears in the window. Try the same prompt at two temperatures to see how much the answers change. **Playground** becomes available once the endpoint is serving, so wait until it is **Running**.

When the answers look right, connect your application and send the same settings as request fields. See [Use the OpenAI client and stream responses](/tir/model-endpoints/how-to/use-the-openai-client-and-stream-responses/).