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ModelActiveProprietaryfamily · Claude

Claude Fable 5.1

Anthropicplatform.claude.com/docs/en/models/fable-5-1/ove

For demanding reasoning and long-horizon agentic work

quality80

Updated 32 min ago · first seen 11 Sept 2026

model_01M293V7EK3CVA2J99BHKR8PHG

Context
1M tokens
T1 · 32 min ago
Released
1 Sept 2026
T1 · 32 min ago
Knowledge cutoff
Jun 2026
T1 · 32 min ago

Specification

Family
Claude

Source:Claude Developer Platform docsT1observed 32 min agohigh

Release date
1 Sept 2026

Source:Claude Developer Platform docsT1observed 32 min agohigh

Status
active

Source:Claude Developer Platform docsT1observed 32 min agohigh

Openness
proprietary

Source:Claude Developer Platform docsT1observed 32 min agohigh

Context window
1M tokens

Source:Claude Developer Platform docsT1observed 32 min agohigh

Max output
128K tokens

Source:Claude Developer Platform docsT1observed 32 min agohigh

Knowledge cutoff
Jun 2026

Source:Claude Developer Platform docsT1observed 32 min agohigh

Training data cutoff
Jun 2026

Source:Claude Developer Platform docsT1observed 32 min agohigh

Modalities
text, image

Source:Claude Developer Platform docsT1observed 32 min agohigh

Input modalities
text, image

Source:Claude Developer Platform docsT1observed 32 min agohigh

Output modalities
text

Source:Claude Developer Platform docsT1observed 32 min agohigh

API model id
claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

API alias
claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

Retirement date
1 Sept 2027

Source:Claude Developer Platform docsT1observed 32 min agohigh

Retirement tentative
Yes

Source:Claude Developer Platform docsT1observed 32 min agohigh

Bedrock model id
anthropic.claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

Claude aws model id
claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

Default effort
high

Source:Claude Developer Platform docsT1observed 32 min agohigh

Foundry model id
claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

Latency tier
Slower

Source:Claude Developer Platform docsT1observed 32 min agohigh

Thinking
Adaptive (always on)

Source:Claude Developer Platform docsT1observed 32 min agohigh

Vertex model id
claude-fable-5-1

Source:Claude Developer Platform docsT1observed 32 min agohigh

Each value shows its source, tier and observation time. Conflicting claims are kept side by side and flagged — never averaged. How AI Atlas records facts →

Provenance

Attributed facts

26

Source tiers

T126

Freshest observation

32 min ago

Conflicts

None