Fable 5 is unavailable to zero-data-retention organisations

The error

An organisation configured for zero data retention sends a perfectly well-formed request to Fable 5 and gets a rejection rather than a response — not a rate limit, not a malformed-request error, but a flat refusal tied to the account's retention setting rather than anything about the request itself.

Why this specific model is the one that's blocked

Fable 5 requires a data retention window to operate — Anthropic's most capable model needs a short retention period as part of how it runs, and that requirement is incompatible with an organisation-level zero-retention setting by definition, not as a configurable option that could be relaxed per-request. Every other current model in the lineup can run under a zero-retention policy; Fable 5 specifically cannot, which makes it the one model choice a zero-retention organisation has to route around structurally rather than a case-by-case judgement call.

What to route to instead

If your organisation is on zero data retention, the practical fix is choosing a different model for the workload that would otherwise have used Fable 5 — Opus 5 is the closest capability match in the current lineup and runs under zero retention without issue. This isn't a workaround or a degraded substitute so much as a different constraint on model choice that has to be factored in alongside cost and task shape: zero-retention status changes which models are even eligible before price and capability enter the decision at all.

Where else this surfaces

If your organisation's retention policy is set at the account level, it's worth checking any model-picking logic — a router, a fallback chain, an eval harness that cycles through several models — for a hardcoded reference to Fable 5, since that's the one place a zero-retention account will see this error appear even when nobody explicitly chose Fable 5 for the task. The model picker can help confirm which models remain viable options once a zero-retention constraint is factored into the recommendation.