Default value changed

What changed

Behavior shifts for every call that omits the field.

Affects BetaImageGenTool reachable from 6 operations.

"gpt-image-2" → "gpt-image-2.6-sunburst"

Who is affected

Code that calls OpenAI's BetaImageGenTool objects, used by 6 OpenAI operations.

Before and after

Based on OpenAI’s published API specification. How severity is decided.