claude-fable-5-1 open weights and deployment
Status: Unavailable. Anthropic publishes no Claude Fable 5.1 weights. The model is available on the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry and Claude Platform on AWS; Claude Mythos 5.1, the same model with different safeguards, is limited to Project Glasswing participants.
Need to self-host? Open-weight alternatives: deepseek-flash, glm-5.3-flash.
- License
- Proprietary hosted model
- Hardware note
- Not applicable
- Recommended runtime
- ChinaAPI or the Claude API
- Verified date
- 2026-09-24
Published model card
- Parameter count
- Not disclosed
- Context window
- 1M tokens
- Maximum output
- 128K tokens
- Input/output modalities
- Text and image input; text output
Official sources
- Introducing Claude Fable 5.1 and Claude Mythos 5.1 — Anthropic, retrieved 2026-09-24
- Claude Fable 5.1 model documentation — Anthropic, retrieved 2026-09-24
- Choosing a model — Anthropic, retrieved 2026-09-24
- System Card: Claude Fable 5.1 & Claude Mythos 5.1 — Anthropic, retrieved 2026-09-24