Constant ACCOUNT_NOT_ENTITLED 

pub const ACCOUNT_NOT_ENTITLED: &str = "account_not_entitled";

The provider account may not use the model: it needs a paid plan (Workers AI 5035), has not accepted the model’s agreement (5016), or is blocked (3023). Permanent until an operator acts. Batch-level, handled like AUTH_FAILED: an admission refusal when the call’s first provider call meets it, otherwise it stops the call and every item left unanswered carries it. Never stored.