Claude Fable 5.1

Available

Source-backed identifier on the Anthropic API. Unverified details are marked below.

Access details: Anthropic API

Versioned identifier · Identity and lifecycle apply to this exact identifier and serving surface.

claude-fable-5-1

Source check: Sep 13, 2026

Sources & notes →

Capabilities & limits

Context window: 1M
Maximum output: 128K
Image input: Supported
Tool calling: Supported
Structured output: Not verified

Documented interfaces and limits. These are not measures of model quality.

Pricing

USD / 1M tokens

Input: $10.00Derived from the captured rate card's standard token row.
Output: $50.00Derived from the captured rate card's standard token row.

USD per million standard text tokens. Detailed cache, batch and other pricing conditions appear in the rate card.

Full rate card 5 rates

Amounts in USD. Check the unit and conditions on each rate.

Base input tokens

$10.00 per 1M tokens

Claude API global standard

Output tokens

$50.00 per 1M tokens

Claude API global standard

Cache hits and refreshes

$0.25 per 1M tokens

prompt caching

5 minute cache writes

$12.50 per 1M tokens

prompt caching
5 minute duration

1 hour cache writes

$20.00 per 1M tokens

prompt caching
1 hour duration

Full 1M-token context window uses standard pricing, including requests over 200K input tokens; prompt caching and Batch discounts remain at standard rates.

Price history

Observed Sep 13, 2026

Input $10.00 per million tokens

Derived from the captured rate card's standard token row.

Observed Sep 13, 2026

Output $50.00 per million tokens

Derived from the captured rate card's standard token row.

Technical details

Training / knowledge cutoff: Jun 2026
Input modalities: text, image
Output modalities: text

3 details not verified

Parameters
Active parameters
Architecture

The current model overview documents adaptive thinking and a 1M-token context window with 128K maximum output.

From Anthropic

Official announcement ↗

How they describe it

For demanding reasoning and long-horizon agentic work

What they say is different

Our most advanced models for coding and knowledge work

Verbatim provider claims · not an independent assessment

Release & lifecycle

Availability applies to this exact identifier on Anthropic API.

First API availability: Sep 1, 2026
available: Observed Sep 13, 2026