Native Fields

Pass provider-native parameters directly with native_fields — for options outside the OpenAI-compatible surface.

Some provider features have no equivalent in the OpenAI Responses API surface. native_fields is a pass-through container that lets you send those parameters using the provider's own field names, without wrapping them in OpenGateway-specific abstractions.

How to use it#

Add native_fields at the top level of your request body. Its keys map directly to the provider's native API, and you can combine several at once.

{
"model": "google/gemini-2.5-pro",
"input": "Write a detailed technical analysis.",
"native_fields": {
"thinking_config": { "thinking_budget": 16000 },
"top_k": 40
}
}

OpenGateway forwards the contents of native_fields to the provider as-is. No normalization is applied to these fields.

Provider support#

ProviderSupported fields
Google (Gemini Responses)thinking_config, safety_settings, top_k, labels

thinking_config controls the Gemini thinking budget directly; when present, OpenGateway uses it as-is and does not derive a budget from reasoning.effort.

native_fields vs. normalization#

native_fields bypasses normalization entirely. When you use it, the gateway forwards the field verbatim — if the provider rejects it, you get the provider's error back instead of a corrected request.

Use native_fields when you need exact provider behavior. Use the standard parameters when you want the gateway to handle cross-provider compatibility for you.