When adding or extending client/provider integrations, enforce a single, predictable configuration-resolution contract: - **Args → env fallbacks:** For each required setting (e.g., `api_version`, `region`), accept an explicit argument, otherwise fall back to the corresponding environment variable(s). Only raise a clear error when *neither* is provided. - **Keep derived config coherent on overrides:** If your client derives other settings from config (e.g., `base_url` derived from `region`), then `copy()`/cloning/overrides must recompute or correctly forward dependent values so behavior matches the updated config. - **Prevent invalid config-mode switches:** If auth modes are mutually exclusive (e.g., SigV4 vs API key, or token vs API key), ensure `copy()` clears/normalizes incompatible fields instead of forwarding stale state. - **Stability across releases & feature flags:** - If an integration requires adding public exports (like `__init__.py`), update the generator configuration so the change persists across automated releases. - Manage optional feature dependencies (e.g., async HTTP support) via extras/feature flags and raise a focused runtime error when the optional dependency isn’t installed. Example patterns: ```python # 1) Env fallback + clear error resolved_api_version = api_version or os.environ.get("OPENAI_API_VERSION") if not resolved_api_version: raise ValueError("Must provide api_version or set OPENAI_API_VERSION") # 2) copy(): keep dependent config consistent new_region = region or self._region # ensure base_url is recalculated when region changes _forward_base_url = {} if region else {"base_url": self.base_url} # 3) copy(): normalize mutually-exclusive auth fields # if switching to api_key, drop credential provider forwarded_credential_provider = None if "api_key" in kwargs else (credential_provider or self._credential_provider) ``` Add unit tests that cover: - override of primary config triggers correct recomputation of dependent config (e.g., `region` → `base_url`), - explicit switches between mutually exclusive auth modes behave as expected, - missing required config produces the intended error message and does not fail later with confusing downstream exceptions.