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

# Temperature parameter not supported in GPT-5 models

export const plans_0 = "Any"

export const deployments_0 = "Braintrust-hosted"

export const data_plane_version_0 = undefined

export const use_case_0 = "Use case - Prompts using GPT-5 models"

<Note>
  **Applies to:**

  * Plan - {plans_0}
  * Deployment - {deployments_0}
  * {data_plane_version_0}
  * {use_case_0}
</Note>

Summary

**Issue:** The `temperature` parameter appears disabled or has no effect when using GPT-5 models in Braintrust prompts.

**Cause:** OpenAI's GPT-5 model family does not support the `temperature` parameter in their API.

**Resolution:** Use a different model (GPT-4, GPT-3.5-turbo, or other compatible models) if temperature control is required.

## Resolution Steps

### If temperature control is required

#### Step 1: Switch to a compatible model

Change your prompt to use GPT-4, GPT-4-turbo, or GPT-3.5-turbo, which support the `temperature` parameter.

#### Step 2: Configure temperature setting

Set your desired temperature value (0.0 to 2.0) in the model parameters.

### Otherwise, if using GPT-5 is required

#### Step 1: Accept default behavior

GPT-5 models use OpenAI's default sampling behavior without temperature control.

#### Step 2: Adjust prompt design

Modify prompt instructions to guide output style instead of relying on temperature.

## Additional Information

This is expected behavior from OpenAI's API, not a Braintrust limitation. Refer to OpenAI's model documentation for complete parameter support details for each model family.