Claude Fable 5.1

Anthropic · Claude Fable line · flagship

Released September 1, 2026Latest in the line

What changed

Anthropic's top model, refreshed: big jumps on long coding and scientific-research tasks, and cached input now costs 75% less — same headline price as Fable 5.

Compared with Claude Fable 5 · the model it replaces

Finishes over half of long multi-step coding tasks

Terminal-Bench 4.0 — long agentic coding sessions in a terminal

55.8%

up from 42.0% · +14 points

Doubles its score on agentic scientific research

Terminal-Bench-Science 0.1 — running real research workflows end to end

52.6%

up from 24.7% · more than doubled

Same price — and cached input now costs 75% less

Price per 1M tokens — what developers pay, input / output

$10 / $50

same as Fable 5 · cache reads now $0.25

Where the Claude Fable line stands

Claude Fable 5.1 is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.

Claude Fable 5.1

Anthropic · Claude Fable line · flagship
Just releasedreleased 8 days ago — usual gap is ~84
Released Sep 1, 2026 · what changed →
Days since last release
Claude Fable 5.1 · Sep 1, 2026
8
days
Usual gap
84
days
Recent gaps
Claude Fable 5.1 · Sep 2026
84

Every Claude Fable release

Newest first. See the full line with every card →

  1. Sep 1, 2026Claude Fable 5.1 · this page
  2. Jun 9, 2026Claude Fable 5

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