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Claude Fable 5 vs Claude Mythos Preview

This page is context-first: how much text each model can take in one request. Full specs adds capabilities and limits; the pricing matrix below is only about $/million tokens from hosts that list both models.

Anthropic

Model

Claude Fable 5

Image inputTool calling

Context window

1M

1,000,000 tokens · ~750K words

Model page
Anthropic

Model

Claude Mythos Preview

Image inputTool calling

Context window

1M

1,000,000 tokens · ~750K words

Model page

Context window · side by side

Bar length is relative to the larger of the two windows (100% = max of this pair). This is not pricing.

Claude Fable 51M
Claude Mythos Preview1M

Same context window size for both models.

Claude Fable 5 and Claude Mythos Preview have identical context windows (1000K tokens).

Full specs

Context, output, capabilities, and dates. Green highlights the favorable value where we compute a winner.

SpecClaude Fable 5Claude Mythos Preview
Context window1,000,000 tokens (1000K)1,000,000 tokens (1000K)
Max output tokens128,000 tokens (128K)128,000 tokens (128K)
Speed tierBalancedBalanced
VisionYesYes
Function callingYesYes
Extended thinkingYesYes
Prompt cachingYesNo
Batch APIYesYes
Release dateJun 2026N/A

Pricing matrix

Dollar rates only: hosts that list both models, per 1M tokens. For how much text fits, use the context section above — not this table.

ProviderClaude Fable 5 inClaude Fable 5 outClaude Mythos Preview inClaude Mythos Preview out
Aws Bedrock

Frequently asked questions

Claude Mythos Preview has a larger context window: 1000K tokens vs 1000K. For long documents, large codebases, or extended agent sessions, the larger context window reduces the need to chunk inputs or summarize history.

Powered by Mem0

Use a smaller model.
Get better results.

Mem0 gives your AI long-term memory so you stop re-sending context on every call. That means you can use a smaller, faster, cheaper model — and still get better answers.

Example: a multi-turn chat session

Without Mem0~128K tokens sent
Full history
Repeated info
Old context
With Mem0~20K tokens sent
Key memories
Current turn

80% less to send — works with any model