optionsFor

Options configured for role under provider, or null if the role says nothing about it.

Reads the nested shape, in which a role names a different model per provider:

embabel:
  models:
    roles:
      cheapest:
        openai:
          model: gpt-4.1-nano
        anthropic:
          model: claude-haiku-4-5
          temperature: 0.0

optionsFor("cheapest", "anthropic") returns those Anthropic options, temperature included. optionsFor("cheapest", "mistral") returns null - the role is configured, but says nothing about that provider, so the caller falls back to the flat embabel.models.llms map.

A null provider returns null rather than guessing: with no active credential there is no provider to select within, and the flat map is the right answer. Provider names are matched case-insensitively, because they arrive from user-supplied credentials as often as from yaml.