Claude Fable 5.1 · context window1M token context window

Valid from

2026-09-01

Valid until

still holds

Published

no source on record carries a date

Recorded by AsOf

2026-11-04

Checked

2026-11-04 · its source page states the value and the date

Confidence

0.95

Sources

“Both models support a 1M token context window by default, 128k max output tokens, and always-on adaptive thinking , at $10 / $50 USD per MTok”— what the page says, read 2026-11-04

• https://platform.claude.com/docs/en/release-notes/overviewprimary · platform.claude.com

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