What the agent returns for ONE field. Flat and fully-nullable rather than a discriminated union:
OpenAI strict structured output requires every key to be present, so a union of value shapes
forces the model to satisfy branches that do not apply. The runner reads only the member that
matches the field's type and ignores the rest.
What the agent returns for ONE field. Flat and fully-nullable rather than a discriminated union: OpenAI strict structured output requires every key to be present, so a union of value shapes forces the model to satisfy branches that do not apply. The runner reads only the member that matches the field's type and ignores the rest.