Model board / Claude Fable 5.1

Verified 2026-09-03 against the pages listed below. Prices are USD per 1M tokens, list rate — no committed-use, enterprise or volume discount.

1h cache write $20.00. The cache read is the number to look at: $0.25 is 0.025x the base input rate, where every other Claude row pays 0.1x. On this row caching is four times the saving it is elsewhere on the board

full 1M window at standard rates; up to 128K output per request

read 0.025x input — not the 0.1x other Claude rows pay; 5m write 1.25x, 1h write 2x

Watch out

$50 output is the top of this board. Adaptive thinking is always on, so there is no non-thinking mode to fall back to; effort is tunable and defaults to high. Retirement committed no sooner than 2027-09-01

What we would use it for

Demanding reasoning and long-horizon agentic work, per Anthropic's own guidance

What this has cost, week by week

Output price at each refresh since 2026-09-03. A vendor change is the provider changing its price. Our correction means this board changed what it prints and the provider's charge did not move — the two are never merged, because publishing the second as the first would be a price rise that never happened.

Nothing has moved since we started tracking it.

Where these numbers came from

• https://platform.claude.com/docs/en/about-claude/pricing
• https://platform.claude.com/docs/en/build-with-claude/prompt-caching
• https://platform.claude.com/docs/en/about-claude/models/overview

No number on this page was written that was not read from one of those pages on 2026-09-03. If one is wrong, send us the source URL and it is corrected in the next weekly refresh, with a changelog line saying what was wrong — contact@naderu.com.

The rest of the board

This row sits alongside 53 others on the model board, refreshed every week. The same data as JSON, and the terms for using it, are at /board-data.