Claude Fable 5.2's first announcement came from an AWS price list
SummaryAmazon's public Bedrock price file listed Claude Fable 5.2 and Mythos 5.2, at 20% below the 5.1 models, about 48 minutes before Anthropic announced them on Nov. 9.
· MODEL Editors · 2 min read
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What happened. On Monday, Nov. 9, Amazon's public AWS Price List file for Bedrock foundation models carried a publication time of 10:09 a.m. PT. It included two models Anthropic had not announced yet: Claude Fable 5.2 and Claude Mythos 5.2, each listed in 35 AWS regions. (AWS Price List (opens in a new tab)) X users who watch these files posted the prices starting at 10:19 a.m. PT, some noting there was no announcement from Anthropic yet. At 10:57 a.m. PT, @claudeai posted (opens in a new tab) "Introducing Claude Fable 5.2 and Claude Mythos 5.2," with a launch video. By early afternoon that post showed about 2.5 million views on X.
What the price file said. For Claude Fable 5.2 on Bedrock's global endpoint in US East (N. Virginia), the file lists $8 per million input tokens and $40 per million output tokens, down from $10 and $50 for Claude Fable 5.1. Cache reads drop from $0.25 to $0.20 per million tokens and five-minute cache writes from $12.50 to $10. That is 20% lower on every line we checked. Regional endpoints cost 10% more ($8.80 in, $44 out). Mythos 5.2 has the same prices.
What Anthropic confirmed. Anthropic's release notes give the same $8 / $40 pricing and say Fable 5.1 and Mythos 5.1 cost $10 / $50. Both 5.2 models have a 1 million token context window and 128,000 max output tokens. Fable 5.2 is available on the Claude API, Amazon Bedrock, Google Cloud and Microsoft Foundry. Mythos 5.2 is limited to organizations verified through Anthropic programs such as the Cyber Verification Program. A new fast mode for Fable 5.2 on the Claude API costs $16 / $80 per million tokens. Anthropic says the 5.2 models generate output up to 30% faster than the 5.1 versions. (Anthropic release notes (opens in a new tab), Anthropic (opens in a new tab))
Why builders should care. If you run Fable 5.1 through the API, the same token count costs 20% less on 5.2 at list price. Read the migration notes before switching: Anthropic says a 5.2 request returns a 400 error if your code edits the system prompt, tools or an earlier message and then sends back a later 5.2 thinking block, and the older computer-use tool version is rejected outside Bedrock. And if you want launch news early, public price files are worth watching.
Caveats. The 10:09 a.m. time is the publication date inside the AWS file, not proof of when people first saw it. The speed claims are Anthropic's. Not tested by MODEL.
Disclosure: Not sponsored. No affiliate links. Not tested by MODEL.
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