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

# unsupported_parameter

> Unsupported parameter (HTTP 400)

| | |
| - | - |
| HTTP status | `400` |
| OpenAI `type` | `invalid_request_error` |
| Anthropic `type` | `invalid_request_error` |
| Retry | No. Error responses carry `x-should-retry: false`. |

## What it means

The request uses a field Antara doesn't support, or one the model can't honor, such as `tools` on a model without tool support, `n` other than 1, or `/v1/responses` on a model whose runtime doesn't serve it. Each endpoint's field table is in [Models](https://docs.antarah.dev/models.md) and the API reference.

## What to do

Remove the field or pick a model that supports it (`GET /v1/models` lists each model's capabilities).


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