Anthropic
CurrentClaude Fable 5.1
Anthropic's model for demanding reasoning and long-horizon agentic work, with a 1,000,000-token context window.
Anthropic describes it as
“For demanding reasoning and long-horizon agentic work”
Last verified:
Key facts
- Context window
- 1,000,000
- Max output
- 128,000
- Input price
- $10.00
- Output price
- $50.00
- Released
- Sep 1, 2026
- Knowledge cutoff
- Jun 2026
- API model ID
- claude-fable-5-1
tokens
tokens
per 1M tokens, standard
per 1M tokens, standard
- Anthropic's pages list a context window and a maximum output but do not state a separate maximum-input figure.
- Anthropic's page does not list a 300K batch-output option for this model.
About Claude Fable 5.1
Claude Fable 5.1 is positioned by Anthropic for demanding reasoning and long-horizon agentic work, and is the highest-priced of its four current models at $10 input and $50 output per million tokens. Anthropic says it "extends Claude Fable 5 at the same input and output prices, with cache reads at a quarter of the cost". It has a 1,000,000-token context window and up to 128,000 output tokens.
API pricing
Per-token API prices from the provider's pricing page. Thresholds and processing modes are shown explicitly, not folded into one number.
| Rate | Price |
|---|---|
| Input | $10.00 |
| Cached input | $0.25 |
| Output | $50.00 |
| Cache write (5 minutes) | $12.50 |
| Cache write (1 hour) | $20.00 |
| Rate | Price |
|---|---|
| Input | $5.00 |
| Output | $25.00 |
- Cache write prices are shown for 5-minute and 1-hour retention.
- Setting inference_geo to "us" applies a 1.1x multiplier on Claude 4.6 and later models.
- Anthropic lists cache reads for this model at 0.025x the base input price.
Modalities and capabilities
What the provider documents for this model. “API tool” means it needs a provider tool or endpoint rather than being native to the model.
- Input modalities
- Text, Image, PDF
- Output modalities
- Text
- ReasoningReasoning: ✓ Yes
Adaptive thinking, always on.
- Tool / function callingTool / function calling: ✓ Yes
- Structured outputsStructured outputs: ✓ Yes
- Web searchWeb search: ✓ Yes · API tool
Web search tool.
- Code executionCode execution: ✓ Yes · API tool
Code execution tool.
- Computer useComputer use: ✓ Yes · API tool
On the Claude API, through computer_toolset_20260801.
- Image generationImage generation: ✕ No
Output is text only.
- Prompt cachingPrompt caching: ✓ Yes
Minimum cacheable prompt length is 512 tokens.
- Batch APIBatch API: ✓ Yes
Benchmarks
Individual named benchmarks only: there is no overall score. Vendor-reported results come from the model maker's own launch materials. Scores from different sources, versions or settings are not directly comparable.
| Benchmark | Score | Source type | Reported by |
|---|---|---|---|
| CursorBench (v4.0) | 51.8% | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
| FrontierCode (v1.1, Main) | 50.3% | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
| GDPval-AA (v2.1) | 1735 | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
| Humanity's Last Exam (with tools) | 65.6% | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
| OSWorld (v2.1, partial credit) | 80.7% | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
| Terminal-Bench (v4.0)Anthropic gives a standard error of ±1.6–2 points for its Claude models other than Opus 5.5. | 55.8% | Vendor-reported | Anthropic (comparison column on the Opus 5.5 page)Sep 22, 2026 |
Availability and API identifiers
| Surface | Identifier |
|---|---|
| Claude APIEvery Claude model ID is a pinned snapshot; there is no separate dated ID. | claude-fable-5-1 |
| Amazon Bedrock | anthropic.claude-fable-5-1 |
| Google Cloud (Google-managed and Anthropic-managed) | claude-fable-5-1 |
| Microsoft Foundry | claude-fable-5-1 |
| Claude Platform on AWS | claude-fable-5-1 |
Limitations and caveats
API vs. apps. These limits and prices describe the Claude API model. The Claude apps can apply different limits and are billed through subscriptions, not per token.
- Anthropic lists retirement as not sooner than September 1, 2027.
- Anthropic says Claude 4.7 and later models produce approximately 30% more tokens for the same text than earlier Claude models.
- Anthropic says forced tool use returns an error on this model.
- Anthropic says only Fable 5.1 and Mythos 5.1 can read its thinking blocks.
Sources
Last verified against these sources on Oct 31, 2026. Prices and limits change; follow the links for the live figure.
- Anthropic docs — Claude Fable 5.1
Supports: status, release date, knowledge cutoff, context window, max output, modalities, pricing
OfficialChecked Oct 31, 2026
- Anthropic docs — Models overview
Supports: status, context window, max output, modalities, capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Pricing
Supports: pricing
OfficialChecked Oct 31, 2026
- Anthropic docs — Structured outputs
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Web search tool
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Computer use tool
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Code execution tool
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — PDF support
Supports: modalities, capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Prompt caching
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic docs — Batch processing
Supports: capabilities
OfficialChecked Oct 31, 2026
- Anthropic — Claude Opus 5.5 launch page
Supports: benchmarks
Anthropic launch page; scores are Anthropic-reported.
Vendor benchmarkChecked Oct 31, 2026