Gateway Fable model aliases

Work with Fable

Claude Fable 5.1 and Claude Fable 5 are the most capable models in Claude Code, suited to tasks larger than a single sitting. They sustain long autonomous sessions, investigate before acting, and verify their work more often than smaller models. Fable 5.1 is the newer release.

Neither Fable model is the account-type default on any plan or provider. Select one explicitly:

• Fable 5.1: run /model fable, or launch with claude --model fable. In Claude apps gateway sessions, where the alias resolves to Fable 5, run /model claude-fable-5-1 instead.
• Fable 5: select it by model ID. On the Anthropic API, run /model claude-fable-5 or launch with claude --model claude-fable-5. On other providers, use your provider's Fable 5 model ID or pin it with ANTHROPIC_DEFAULT_FABLE_MODEL.

If you connect to the Anthropic API directly and your user settings hold claude-fable-5 or claude-fable-5[1m] as the model, for example because you selected Fable in the /model picker before v2.1.257, Claude Code changes that saved value to the fable or fable[1m] alias the first time you run v2.1.257 or later. The startup model line shows (auto-updated) once. A claude-fable-5 value in project, local, or managed settings stays as it is.

Requests that a Fable model's safety classifiers flag, most often in cybersecurity and biology domains, trigger automatic model fallback.

To get the most from Fable:

• Describe the outcome, not the steps: hand it the result you want and let it plan the path. To keep it working toward that outcome, set a goal.
• Hand it ambiguous problems: root-cause investigations, outage debugging, and architecture decisions are where the extra investigation and verification pay off.
• Skip the verification reminders: it verifies its own work with less prompting, so reminders to test or check are usually unnecessary.
• Size up larger tasks: give it work you would normally break into pieces. It holds long sessions without losing the thread.

Fable 5.1 requires Claude Code v2.1.257 or later. If a request for it from an older version fails, see Claude Code does not support this model. Run claude update to upgrade. For availability under zero data retention, see Model availability under ZDR.

On the Anthropic API, a Fable model appears in the /model picker unless availableModels or organization model restrictions exclude it. When your organization can't use Fable at all, for example under zero data retention, the row stays in the picker grayed out, with a note on why.

Fable and usage credits

Depending on your plan and seat tier, Fable usage can bill to usage credits instead of drawing on your plan's included limits. When it does, the /model picker shows "Requires usage credits" on the Fable row. To manage usage credits, see Add usage credits to your subscription.

In interactive sessions, Claude Code shows a consent prompt before a Fable request bills usage credits. Members of Enterprise plans with organization billing don't see the prompt. You can continue on Fable using usage credits or switch to your default model. You can also dismiss the prompt:

• In the /model picker, you keep your current model.
• Mid-session, Claude Code continues the turn on your default model.

After you choose to continue on Fable using usage credits, Claude Code doesn't show the prompt again.

In a session with Remote Control connected, a background session, or an agent team teammate's session, nobody may be at the terminal, so Claude Code holds the mid-session consent prompt for the dialogExpiry deadline, five minutes by default. If nobody has answered by the deadline, Claude Code ends the turn without sending the request and adds a notice to the transcript, which the Remote Control client also shows. Your model selection is unchanged, and Claude Code asks for consent again on your next message.

What you can do while the prompt is waiting depends on the session:

• With Remote Control connected or in a teammate's session, press any key at the terminal to cancel the deadline, and Claude Code waits for your answer.
• In a background session, answer before the deadline.
• If you send a new message from the remote client before anyone has typed at the terminal, Claude Code ends the turn the same way, and your new message starts the next turn. After someone types at the terminal, Claude Code keeps waiting for the answer and queues your new message behind it.

In non-interactive mode with the -p flag and through the Agent SDK, Claude Code never shows the consent prompt. When a Fable request there would bill to usage credits, Claude Code bills it without asking.