"""Explicit chat-only provider compatibility, without exposing reasoning as answers."""
import os


def chat_model_options():
    mode = os.getenv("CHAT_THINKING_MODE", "").strip().lower()
    if mode not in ("", "disabled", "enabled"):
        raise ValueError("CHAT_THINKING_MODE 只允许 disabled、enabled 或留空")
    options = {"timeout": 60, "max_retries": 0}
    if mode:
        options["extra_body"] = {"thinking": {"type": mode}}
    return options