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ANTHROPIC / claude-fable-5-1

Claude Fable 5.1

Long-running reasoning and agents.

01 / SUMMARY

The essential

ORIENTATIONLong-running reasoning

Primary use stated or inferred cautiously from official documentation.

CONTEXT1,000,000 tokens

Maximum input capacity when published by the source.

EXIT128,000 tokens

Documented maximum generation limit.

ACCESSClaude, Claude API and associated clouds

Verified availability channels.

MODEL TYPEText and reasoning

Primary functional family and verified specialties.

LICENSEProprietary

Declared terms for API access, model weights, or self-hosting.

02 / TECHNICAL SHEET

Limits and integration

API IDclaude-fable-5-1
Model typeText and reasoning
Access modelPaid proprietary
LicenseProprietary
DeploymentHosted API
ReleaseSEP 2026
Knowledge cutoffJUN 2026
EntranceText · Image
ExitText
Context window1,000,000 tokens
maximum output128,000 tokens
ReasoningAdaptive thinking always active
Published toolsUse of tools · Web search · Code execution · Computer use
Structured OutingsSupported
Batch processingCompatible · 50% discount
Prompt cacheCompatible · up to 90% savings on reads
Fine-tuningNot published
Verified platformsClaude.ai · Claude API · Amazon Bedrock · Google Cloud · Microsoft Foundry
BEST SUITED FOR

Long-running reasoning and agents.

WORTH MONITORING

Cost and performance depend on the reasoning level.

03 / CAPABILITIES

What it can do

01

Orientation

Long-running reasoning and agents.

02

Context

1.000.000 tokens · 128.000 tokens

03

Tools and integration

Tool use · Web search · Code execution · Computer use

04

Access

Claude, Claude API and associated clouds

Input modalities
TextImage
04 / PRICES

Documented cost

ConceptWorthUnit/condition
Standard input10.00 USD / 1 M tokensStandard API rate
Cached input1.00 USD / 1 M tokensReading reused prefixes
Cache write or storage12,50–20,00 USD / 1 M tokensThe condition varies by provider
Standard output50.00 USD / 1 M tokensMay include reasoning tokens
Batch input5.00 USD / 1 M tokensAsynchronous processing
Batch output25.00 USD / 1 M tokensAsynchronous processing

Consult the primary source before budgeting for a deployment.

i Prices change and may depend on level, region or context length. Check the source before making a decision.

05 / EVALUATIONS

How to read the results

“

A public benchmark provides guidance, but does not replace an evaluation with your data, tools, budget, and error tolerance.

BenchmarkResultMetricSource
Terminal-Bench Science 0.152,6 %AccuracyView source ↗
CursorBench 3.273,4 %AccuracyView source ↗
Humanity's Last Exam65,0 %With toolsView source ↗

Inferama only highlights a “best result” when the metric, test set, configuration, and date allow for an equivalent comparison. The supplier's figures are presented as claims from its own source.

06 / VERSIONS

Chronology

Claude Fable 5.1

Version added to Inferama's verified catalog.

ANALYSIS

Related analysis

Claude Fable 5.1: technical contract, limits, and testing before assigning high-cost tasks
ANALISIS

Claude Fable 5.1: technical contract, limits, and testing before assigning high-cost tasks

Claude Fable 5.1 should be evaluated as an execution contract, not as a capability label. This analysis separates what Google Cloud and Amazon Bedrock declare from what depends on the channel and what a team must measure before granting autonomy to a production workflow.

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BrowseComp: what an agent that finds a difficult fact on the web measures, and why getting it right does not prove it conducts reliable research
ANALISIS

BrowseComp: what an agent that finds a difficult fact on the web measures, and why getting it right does not prove it conducts reliable research

BrowseComp evaluates whether an agent can locate a brief, hard-to-find factual answer through persistent web browsing. It is a useful signal, but a limited one: a high score is not enough to establish research quality, source traceability, or reliability on open-ended tasks.

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CursorBench 3.2: What a Coding-Agent Benchmark Can Say—and Why It Is Not Enough to Choose a Model Outside Cursor
ANALISIS

CursorBench 3.2: What a Coding-Agent Benchmark Can Say—and Why It Is Not Enough to Choose a Model Outside Cursor

CursorBench provides a signal about agent systems evaluated within Cursor’s harness, but a score is not a portable property of a model. The verified public documentation reviewed describes CursorBench 3.1, not 3.2; therefore, any reference to an alleged 3.2 version must be treated as unconfirmed until Cursor publishes its methodology and results.

22 Sep 2026
Claude Fable 5.1: when caching and batch processing reduce cost per task—and when they only shift the bill
GUIA

Claude Fable 5.1: when caching and batch processing reduce cost per task—and when they only shift the bill

The price per million tokens is not enough to choose between a standard call, instruction caching, or batch processing. This guide provides a cost model per correctly completed task for Claude Fable 5.1, including formulas, scenarios, and minimum telemetry. The outcome depends on reusing context before it expires, controlling retries, and accepting—or not—the asynchronous timeline of Batch API.

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Amazon Nova 2 Lite vs. Claude Fable 5.1 for Document Data Extraction: How to Design a Reproducible Comparison
COMPARATIVA

Amazon Nova 2 Lite vs. Claude Fable 5.1 for Document Data Extraction: How to Design a Reproducible Comparison

The available documentation describes the capabilities, pricing, and access policies of Amazon Nova 2 Lite and Claude Fable 5.1, but it does not provide an independent test using a shared corpus. This guide defines a protocol for comparing them in structured document extraction and explains which decisions can be made, which asymmetries must be disclosed, and when neither model should automate the workflow without human review.

22 Sep 2026
Anthropic: how to verify what changes when you use Claude through an API, partner cloud, or product
ANALISIS

Anthropic: how to verify what changes when you use Claude through an API, partner cloud, or product

Adopting Claude is not simply a matter of selecting a model family. The access channel determines which identifier is used, which retirement schedule governs it, which controls each party administers, and which documentation can support a technical decision. This guide offers a method for separating those layers without turning public policies or safety evaluations into guarantees they do not contain.

22 Sep 2026
07 / SOURCES

Traceability