apply_stored_credentials

Export this provider's stored key and endpoint into os.environ.

LangChain's chat-model factories read credentials from process env vars, so a stored key only takes effect once it's copied onto the env var name registered for that provider. This is a no-op when the provider has no env-var mapping (custom auth) or no stored credential.

The key env var is overwritten whether or not it was already set, matching the precedence rule documented on resolve_provider_credential: a credential the user typed in /auth is the most recent deliberate action and should take effect.

Because a key and its endpoint are a coherent pair (a gateway key only works against the gateway URL; a provider-native key only against the provider's own endpoint), the base URL is applied atomically with the key:

• A stored base_url is written to the provider's canonical base-URL env var, and every other base-URL name the SDK reads is cleared so an inherited gateway URL can't leak through an alternate variable.
• No stored base_url (the user left the field blank) clears all of the provider's base-URL env vars, so the SDK falls back to the provider default rather than an inherited gateway URL. This is what prevents a personal key from being shipped to the gateway.

Only the unprefixed canonical names are written, so an explicit DEEPAGENTS_CODE_{VAR} override still wins via resolve_env_var.