Checked Oct 17, 2026
Anthropic
Claude Fable 5.1
Best for: The hardest reasoning, research and long-running agentic coding.
- LMArena text #6 of 416
- Reasoning
- Reads text, images
- Input
- $10
- per 1M tokens
- Output
- $50
- per 1M tokens
- Cached input
- $0.25
- per 1M tokens
- Context window
- 1M
- tokens in one request
- Max output
- 125K
- tokens per reply
- Released
- Sep 1, 2026
- Knowledge cutoff
- Jun 2026
- Weights
- Closed
- API and apps only
Anthropic's top current model. Full 1M context at the standard price (no long-context surcharge). Cached input = cache read price (0.025x base); 5-minute cache writes cost $12.50.
What would Claude Fable 5.1 cost you?
Change the numbers; the chart compares all 10 featured models at the same usage.
What it's good at
From Anthropic's own announcements and docs, linked.
- Built for demanding reasoning and long-running agent work. Anthropic suggests it for tasks where Claude Opus 5.5 still falls short. source
- Better than Fable 5 at long agentic coding, multistep research, and documents, spreadsheets and slides, with stronger reading of dense charts and PDFs and more reliable computer use. source
- The full 1M-token context is billed at the standard rate, and cache reads dropped 75% to $0.25 per million tokens. source
Watch out for
Limits and costs worth knowing before you build on it.
- Slower than the other Claude models, and Anthropic recommends starting with Claude Opus 5.5 for most work.
- Thinking is always on; forced tool use, assistant prefill and custom temperature settings return an error.
- Safety filters send some requests, such as exploit writing and some life-sciences research, to Opus models instead.
- Not on the free Claude plan; Pro users need usage credits.
Scores
Benchmark numbers are as published by Anthropic; we haven't rerun them. Makers use different setups, so don't compare one maker's numbers with another's. The leaderboard rank comes from public blind votes.
| Measure | Result | Source |
|---|---|---|
| LMArena text rank | #6 (1502) | Oct 15, 2026 |
| Terminal-Bench 4.0 (agentic coding) | 55.8% | Anthropic |
| OSWorld 2.0 (computer use, partial credit) | 77.9% | Anthropic |
| GDPval-AA v2 (knowledge work, Elo) | 1853 | Anthropic |
How to start
Try it in the app
The quickest way to see if it suits your work. Open Anthropic's app.
Get an API key
Sign up on Anthropic's developer platform and add billing; you pay per token as shown above. Read the docs.
Call the model
Use this model ID in your Anthropic API requests:
claude-fable-5-1
Host the app you build with it
Claude Fable 5.1 runs on Anthropic's servers, but your bot, agent or n8n workflow needs a home. A small VPS is usually enough, since the heavy work happens at Anthropic.
| Provider | From | Starting plan | Free tier | Our rating | Link |
|---|---|---|---|---|---|
| HostingerChecked | $2.99/mo | Premium (web hosting)20 GB SSD | No (30-day money-back guarantee) | Not rated | VisitOfficial site |
| DigitalOceanChecked | $4/mo | Basic Droplet 512 MiB1 vCPU · 0.5 GB RAM · 10 GiB SSD | Occasional promo credit for new users | Not rated | VisitOfficial site |
| VultrChecked | $2.50/mo | Cloud Compute Regular Performance, IPv6-only 0.5 GB1 vCPU · 0.5 GB RAM · 10 GB SSD | No free tier | Not rated | VisitOfficial site |
| Hetzner CloudChecked | $6.49/mo | CX23 (Cost-Optimized, Intel/AMD)2 vCPU · 4 GB RAM · 40 GB NVMe | No | Not rated | VisitOfficial site |
Compare with the other 9
| Model | Input / 1M | Output / 1M | Context | Arena |
|---|---|---|---|---|
| gpt-oss-120bOpenAI | $0.15 | $0.60 | 128K | #215 |
| Gemini 3.8 FlashGoogle | $0.75 | $3.75 | 1M | #9 |
| DeepSeek V4 ProDeepSeek | $1.32 | $3.96 | 1M | #56 |
| Grok 4.7xAI | $2 | $6 | 500K | #89 |
| Gemini 4 ArgonGoogle | $2 | $10 | 1M | #1 |
| GPT-6.1 SolOpenAI | $2 | $10 | 1.05M | #22 |
| Claude Sonnet 5.5Anthropic | $2 | $10 | 1M | #36 |
| Claude Opus 5.5Anthropic | $4 | $20 | 1M | #3 |
| Claude Fable 5.1Anthropic | $10 | $50 | 1M | #6 |
| GPT-6 AstraOpenAI | $10 | $50 | 1.05M | #30 |
Cheapest first, using 3 input tokens per output token.
Questions
How much does Claude Fable 5.1 cost?
Claude Fable 5.1 costs $10 per million input tokens and $50 per million output tokens at standard API rates, and $0.25 per million cached input tokens (US dollars, checked Oct 17, 2026). It is the 9th cheapest of the 10 models we feature.
How big is Claude Fable 5.1's context window?
1,000,000 tokens for the prompt, documents and conversation in one request. A single reply can be up to 128,000 tokens. How many words that holds depends on the model's tokenizer.
Is Claude Fable 5.1 open source?
No. Anthropic hasn't published its weights, so you use it through the Anthropic API or apps rather than on your own hardware.
When was Claude Fable 5.1 released?
Anthropic released it in Sep 1, 2026.
What is Claude Fable 5.1's knowledge cutoff?
Anthropic gives its training-data cutoff as Jun 2026. For later events it needs web search or documents you provide.
Sources
- Anthropic pricing, checked Oct 17, 2026
- platform.claude.com/docs/en/about-claude/models/overview
- platform.claude.com/docs/en/models/fable-5-1/overview
- platform.claude.com/docs/en/models/fable-5-1/whats-new-fable-5-1
- anthropic.com/claude-fable-and-mythos-5-1
- support.claude.com/en/articles/15424964-claude-fable-models-on-your-plan
Facts checked Oct 17, 2026. Model names belong to their makers; AskGPU isn't affiliated with Anthropic. Spotted something out of date? Tell us at hello@askgpu.com.