Claude Fable 5.2 launches at $8/$40, 20% below Fable 5.1
Anthropic's Fable line gets a 20% price cut, a fast mode and three breaking API changes.
Anthropic released Claude Fable 5.2 on November 9, 2026, together with Claude Mythos 5.2. Anthropic says the two are the same underlying model: Fable 5.2 ships with cybersecurity and biology safeguards and is generally available, while Mythos 5.2 is limited to organizations verified through Anthropic's Cyber and Life Sciences Verification Programs. Both are priced at $8 per million input tokens and $40 per million output tokens, down from $10 and $50 for the 5.1 generation.
What changed
- New model IDs:
claude-fable-5-2andclaude-mythos-5-2. On Amazon Bedrock the ID isanthropic.claude-fable-5-2. - 1M-token context window, 128K max output tokens and always-on adaptive thinking. Default effort on the Claude API is
high. - Optional fast mode at $16 input and $80 output per million tokens. Anthropic says it delivers up to 2.5x higher output tokens per second; set
speed: "fast"on a Messages API request, with no beta header. - Fable 5.2 is available on the Claude API, Claude Platform on AWS, Amazon Bedrock, Claude Models on Google Cloud (Anthropic managed and Google managed) and Microsoft Foundry.
- Both models require 30-day data retention, like Fable 5.1, and are not available under zero data retention unless Anthropic expressly authorizes it. On the platforms Anthropic operates, Fable 5.2 will not be retired before November 9, 2027.
Prices
Per million tokens. Anthropic list prices are from Anthropic's pricing page; RouterPlus rows are from the RouterPlus catalog on the date shown.
| Model | Where | Input | 5m cache write | Cache read | Output |
|---|---|---|---|---|---|
| Claude Fable 5.2 | Anthropic list price | $8.00 | $10.00 | $0.20 | $40.00 |
| Claude Fable 5.2 fast mode | Anthropic list price | $16.00 | — | — | $80.00 |
| Claude Fable 5.1 | Anthropic list price | $10.00 | $12.50 | $0.25 | $50.00 |
| Claude Fable 5.2 | RouterPlus via Anthropic direct API (Nov 10) | $8.00 | $10.00 | $0.20 | $40.00 |
| Claude Fable 5.1 | RouterPlus via Anthropic direct API (Nov 9) | $10.00 | $12.50 | $0.25 | $50.00 |
Anthropic's 1-hour cache writes for Fable 5.2 cost $16 per million tokens, down from $20, and Batch API requests are 50% off list price.
What to do
Moving to Fable 5.2 is a model-ID swap, with three API changes Anthropic lists in its November 9 release notes:
model: "claude-fable-5-1" -> "claude-fable-5-2"- Fable 5.2 enforces the prompt prefix check on every account. If your code edits the system prompt, tools or an earlier message and then sends back a Fable 5.2 thinking block from a later turn, the request returns a 400 error.
- Computer use needs the
computer_toolset_20260801toolset. Requests that declarecomputer_20251124return a 400 error everywhere except Amazon Bedrock. - With the advisor tool (beta), a Fable 5.2 or Mythos 5.2 executor accepts only Fable 5.2 or Mythos 5.2 as its advisor.
On RouterPlus
Updated November 10, 2026: Claude Fable 5.2 is now in the RouterPlus catalog as claude-fable-5-2, through Anthropic's direct API at api.routerplus.com/v1, with a 1M-token context and 128K max output. Claude Fable 5.1 remains available as claude-fable-5-1. The catalog lists both routes with prompt logging retained. Sign up at app.routerplus.com/login for an API key.