ModelClock
Release announced
Released on Sep 1, 2026
Impossibl announced this model on 2026-09-01. ai api.
- Hosting route
- Impossibl platform
- Affected scope
- ai api
- Announced
- Sep 1, 2026
- First seen by ModelClock
- Oct 6, 2026
What the provider published
impossibl.com ↗anthropic/claude-fable-5-1
new model
claude fable 5.1 joins the ai api with a 1m-token context window and adaptive thinking. cache reads bill at $0.25 per million tokens, a quarter of fable 5's rate.
Read from the provider's text; the quote is the provider's exact lines.