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Claude Fable 5.1

Available

An Anthropic model with a 1M-token context window, image input and tool calling. On the Anthropic API since September 1, 2026.

Access details: Anthropic API

The model ID to use in API requests.

claude-fable-5-1
Updated Sep 23, 2026

Capabilities & limits

Context window
1M
Maximum output
128K
Image input
Supported
Tool calling
Supported
Structured output
Supported

Pricing

USD / 1M tokens
Input
$10.00
Output
$50.00

Standard rates per million tokens. Discounts and long-context rates, where offered, are on Anthropic's pricing page.

Full rate card 5 rates

All prices in USD.

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
Sep 13, 2026

Input $10.00 per million tokens

Oct 20, 2026

Input $10.00 per million tokens

Sep 13, 2026

Output $50.00 per million tokens

Oct 20, 2026

Output $50.00 per million tokens

Technical details

Parameters
Not published
Active parameters
Not published
Architecture
Not published
Training / knowledge cutoff
Jun 2026
Input modalities
Text, image
Output modalities
Text

How they describe it

For demanding reasoning and long-horizon agentic work

What they say is new

Our most advanced models for coding and knowledge work

Release & lifecycle

First available
Sep 1, 2026
available
As of Sep 13, 2026
available
As of Oct 20, 2026

Considering a switch?

Specs only go so far. Try both on your own tasks and compare quality, speed and cost.

Compare with GPT-6 Astra →

Prices and availability as of October 20, 2026. Anthropic's own pages have the latest.