Claude Fable 5.1
Anthropic's premium top-end model, built for the hardest reasoning, long-horizon agentic work and high-stakes writing where quality matters more than cost. Sits above Opus as the flagship of the Claude 5 family.
At a glance
Released
Oct 10, 2026
Provider
Anthropic
Context window
1,000,000 tokens
Max output
128,000 tokens
Modalities
Text + image → text
Knowledge cutoff
July 2026
API model ID
claude-fable-5-1License
Proprietary (API only)
Pricing
Standard
Input$10 / 1M
Output$50 / 1M
Batch (50% off)
Input$5 / 1M
Output$25 / 1M
A typical 1,500-token prompt with a 650-token answer costs ≈ $0.048 on the standard tier. Run your own prompt through the calculator →
What's new vs the previous model
Compared withClaude Fable 5 (May 2026)
- Higher reliability on long multi-step agent runs
- Sharper nuance and consistency in long-form writing
- Larger effective context with steadier recall across it
- Premium pricing, the costliest tier in the lineup
- Higher latency than lighter Claude models
Best use cases
High-stakes reasoning
Tackles complex analysis and planning where a wrong answer is expensive.
Long-horizon agents
Drives multi-hour agentic workflows with many tools and steps.
Premium writing
Produces polished, voice-consistent long-form copy and editing.
Strengths & limitations
Strengths
- Top-tier reasoning quality
- Strong long-context recall
- Excellent writing and nuance
- Reliable tool use
Limitations
- Most expensive option
- Slower than fast tiers
How to test it
- No-code: open claude.ai and pick Claude Fable 5.1 from the model switcher — no API key needed.
- Playground: sign in to the Anthropic Console and run prompts in the workbench, then copy the generated code.
- API: create a key in the Anthropic Console and call the API (example below).
curl https://api.anthropic.com/v1/messages \
-H "x-api-key: $ANTHROPIC_API_KEY" \
-H "anthropic-version: 2023-06-01" \
-H "content-type: application/json" \
-d '{
"model": "claude-fable-5-1",
"max_tokens": 1024,
"messages": [{"role": "user", "content": "Explain tokenization in one paragraph."}]
}'Where to get access
Consumer app
Chat with Claude Fable 5.1 in Claude apps (web, macOS, Windows, iOS, Android).
claude.ai ↗