By the toolist.ai editors. Researched from public sources, not hands-on tested by toolist.ai. Updated October 6, 2026; prices checked October 6, 2026.
Claude Fable 5.1: price, context window and benchmarks
Claude Fable 5.1 is Anthropic's most capable model open to all customers, a tier above Opus, at $10 per million input tokens and $50 per million output tokens. Anthropic advises starting with Claude Opus 5.5 for most work and using Fable 5.1 for demanding reasoning and long-horizon agentic work; on Artificial Analysis, Opus 5.5 currently scores higher.
Best for
- Multi-hour or multi-day autonomous projects where Claude Opus 5.5 at high effort has already fallen short
- Teams that need Anthropic's top tier inside the Claude apps (Max, Team and Enterprise plans)
- Prompt-heavy agents, since cache reads cost only $0.25 per million tokens against $10 for fresh input
Key facts
| Fact | Claude Fable 5.1 | Source |
|---|---|---|
| Provider | Anthropic | Claude docs: Pricing |
| API model name | claude-fable-5-1 | Claude docs: Claude Fable 5.1 |
| Released | September 1, 2026 | Claude docs: Claude Fable 5.1 |
| Input price | $10 per million tokens | Claude docs: Pricing |
| Cached input price | $0.25 per million tokens | Claude docs: Pricing |
| Output price | $50 per million tokens | Claude docs: Pricing |
| Context window | 1,000,000 tokens | Claude docs: Claude Fable 5.1 |
| Maximum output | 128,000 tokens | Claude docs: Claude Fable 5.1 |
| Knowledge cutoff | June 2026 | Claude docs: Claude Fable 5.1 |
| Input and output | Text and images in; text out | Claude docs: Claude Fable 5.1 |
| Reasoning | Adaptive thinking is always on. Effort levels low to max; high is the API default | Claude docs: Claude Fable 5.1 |
| API and cloud platforms | Claude API, Amazon Bedrock, Google Cloud and Microsoft Foundry | Claude docs: Claude Fable 5.1 |
| In the apps | Claude apps on Max, Team (premium seats) and Enterprise, and on Pro through usage credits; not on Free | Claude plans and pricing |
| Data retention | Requires 30-day data retention; not available under zero data retention unless Anthropic authorizes it | Claude docs: API and data retention |
Cache writes cost $12.50 per million tokens (5-minute cache) or $20 (1-hour cache). The Batch API costs half. There is no long-context surcharge and no fast mode.
What Claude Fable 5.1 costs a month
Three typical workloads, priced at the standard API rates above. We calculated these; the provider does not publish them.
| Workload | Tokens a month | Cost a month |
|---|---|---|
| Support chatbot 100,000 replies, each 3,000 input and 400 output tokens, no caching | 300M in, 40M out | $5,000 |
| Document Q&A 5,000 questions over the same 60,000-token document set (90% cache hits), 800 output tokens each | 300M in, 4M out | $568 |
| Coding agent 200 tasks, each 1.5 million input tokens (90% cache hits) and 50,000 output tokens | 300M in, 10M out | $868 |
Reasoning models bill their thinking as output tokens, so heavy reasoning can raise the output count several times. Cache-write charges are not included.
Benchmarks
| Benchmark | Score | Source |
|---|---|---|
| Artificial Analysis Intelligence Index max effort | 53.4 | Artificial Analysis: Claude Fable 5.1 (max) |
| Intelligence Index at everyday effort high effort, the API default | 51.2 | Artificial Analysis: Claude Fable 5.1 (high) |
| Coding Agent Index Claude Code harness, max effort | 62.2 | Artificial Analysis: Coding agents |
| Terminal-Bench 4.0 max effort | 52.0% | Artificial Analysis: Claude Fable 5.1 (max) |
| Humanity's Last Exam max effort | 59.1% | Artificial Analysis: Claude Fable 5.1 (max) |
| GDPval-AA v2.1 (Elo) max effort | 1758 | Artificial Analysis: Claude Fable 5.1 (max) |
| SciCode max effort | 63.1% | Artificial Analysis: Claude Fable 5.1 (max) |
| Terminal-Bench-Science 0.1 max effort | 43.3% | Artificial Analysis: Claude Fable 5.1 (max) |
| GPQA Diamond max effort | 93.7% | Artificial Analysis: Claude Fable 5.1 (max) |
Speed: about 57.8 output tokens a second, 22.7 seconds to the first token (high effort, Anthropic API; Artificial Analysis: Claude Fable 5.1 (high)).
Benchmark and speed data marked as such come from Artificial Analysis.
What changed
Compared with Claude Fable 5, input and output prices stay at $10 and $50 per million tokens, but cache reads fall 75%, from $1 to $0.25. Fable 5.1 is the same model as Claude Mythos 5.1, with tighter safeguards, and unlike Mythos it is generally available. (Anthropic: Introducing Claude Fable 5.1 and Claude Mythos 5.1)
Claude Fable 5.1 compared
Other models
- GPT-6.1 Sol: $2 in, $10 out per million tokens
- Claude Opus 5.5: $4 in, $20 out per million tokens
- GPT-6 Sol: $2 in, $10 out per million tokens
- GPT-6 Astra: $10 in, $50 out per million tokens
- Claude Opus 5: $5 in, $25 out per million tokens
All prices side by side: AI model API price table. How we research: our method.
Sources
- Anthropic: Introducing Claude Fable 5.1 and Claude Mythos 5.1 (checked 2026-10-06)
- Claude docs: Claude Fable 5.1 (checked 2026-10-06)
- Claude docs: Pricing (checked 2026-10-06)
- Claude docs: API and data retention (checked 2026-10-06)
- Claude plans and pricing (checked 2026-10-06)
- Artificial Analysis: Claude Fable 5.1 (max) (checked 2026-10-06)
- Artificial Analysis: Claude Fable 5.1 (high) (checked 2026-10-06)
- Artificial Analysis: Coding agents (checked 2026-10-06)
- OpenRouter: Claude Fable 5.1 (checked 2026-10-06)