Velokey

Claude Fable 5

AnthropicChatin 8 · out 40 Credits / 1M tokens≈$8 / $40Available
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Claude Fable 5 is Anthropic's Mythos-class frontier model, safeguarded for general use and state-of-the-art across nearly every tested capability. Access it through Velokey's unified endpoint with below-list pricing.

SOTA across benchmarksAgentic software engineeringVision processingLong-horizon memory

Use cases

Large-scale codebase migration · Document-heavy knowledge work

Input

Text, image

Output

Text

Billing

Per token

0.7
02
2048
2568192
claude-fable-5

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Sign up to get $0.5 in free credits — about 20 free images

Pricing details

Transparent usage-based pricing with no hidden fees.

Detailed Pricing

Usage-based pricing breakdown

SpecPriceOfficialSavings
Input/1M tokens8 Credits≈$810 Credits-20%
Output/1M tokens40 Credits≈$4050 Credits-20%
Cache Read/1M tokens0.8 Credits≈$0.81 Credits-20%
Cache Write/1M tokens10 Credits≈$1012.5 Credits-20%

Billing Rules

  • Output price varies by model, resolution, quality, duration, or token usage.
  • Uploaded reference files may be charged separately when supported.
  • Add-on capabilities such as web search or image search may be billed per request.
  • Token-based models are billed by input and output tokens.
  • If the primary route is unavailable, Velokey may automatically switch to a stable fallback route when possible.
  • Usage is pay-as-you-go with transparent credit deduction.

* Final cost depends on the generated result.

Related models

Explore other models in the same family.

Affordable Claude Fable 5 API

Access Anthropic's Mythos-class frontier model on Velokey — state-of-the-art across benchmarks, safeguarded for general use, with a unified endpoint and discount on official pricing for production-ready apps.

Meet Claude Fable 5 and its API integration

Claude Fable 5 is Anthropic's Mythos-class frontier model — the safeguarded version made safe for general use, falling back to Opus 4.8 on high-risk requests in fewer than 5% of sessions. It reaches state of the art on nearly all tested AI capability benchmarks, with standout strength in software engineering, knowledge work, vision processing, and scientific research.\n\nVelokey offers an affordable, integration-friendly Claude Fable 5 API: a unified chat endpoint, a clean request flow, and a discount on top of official pricing — ready to drop into production systems, agent pipelines, and automation tools.

State-of-the-art across benchmarks

Reaches state of the art on nearly all tested AI capability benchmarks, with particular strength in software engineering, knowledge work, vision, and scientific research — a genuinely frontier-level model for demanding work.

View Documentation →
State-of-the-art across benchmarks

Agentic software engineering at scale

Compresses months of engineering into days. At Stripe, a 50-million-line Ruby migration was completed in a single day, sustaining focus and coherence across a very large codebase.

View Documentation →
Agentic software engineering at scale

Precise vision and reasoning

Extracts precise numbers from scientific figures and rebuilds working web apps from screenshots alone — it even completed Pokémon FireRed from raw screenshots, turning visual input into reliable action.

View Documentation →
Precise vision and reasoning

Long-horizon memory

With file-based memory in Slay the Spire, it improved 3x more than Opus 4.8 and reached the final act 3x more often, sustaining goals across long, multi-step tasks.

View Documentation →
Long-horizon memory

How to deploy the Claude Fable 5 API on Velokey

Just a few steps to start calling.

1

Sign up and get an API Key

Sign in to the Velokey dashboard to generate an API Key that authenticates every request sent to Claude Fable 5.

2

Set the model

Set model to claude-fable-5. As the safeguarded release, it transparently falls back to Opus 4.8 on high-risk requests in fewer than 5% of sessions, so everyday work runs uninterrupted.

3

Integrate and start calling

Send requests to Velokey's unified /v1/chat/completions endpoint to power assistants, agents, and automation, and manage usage from one dashboard.

Claude Fable 5 real-world use cases

From engineering to knowledge work, across many high-autonomy scenarios.

Large-scale codebase migration

Compresses months of engineering into days — the approach that let Stripe finish a 50-million-line Ruby migration in a single day.

Document reasoning

Posts the highest score on the Hebbia Finance Benchmark, fit for finance, legal, and research work that hinges on dense documents.

Screenshot-to-app rebuilding

Rebuilds working web apps from screenshots alone, turning visual references and mockups directly into shippable code.

Scientific figure extraction

Extracts precise numbers from scientific figures and charts, supporting research and data workflows that demand visual precision.

Long-horizon agents

With file-based memory it improved 3x more than Opus 4.8 in Slay the Spire, sustaining goals across long, multi-step autonomous tasks.

Knowledge work

State-of-the-art knowledge work across dense reports and research, generating structured conclusions from large bodies of material.

Why choose Velokey for Claude Fable 5

A discount on official pricing

Call Claude Fable 5 at $10 / 1M input and $50 / 1M output — roughly half the price of Mythos Preview — with a further discount on Velokey and no mandatory subscription.

Unified API interface

One API Key accesses Claude Fable 5 and other models — no juggling multiple accounts and keys, simplifying integration.

Thorough docs and examples

Endpoint references, parameter details, and worked examples help you integrate Claude Fable 5 quickly and make the most of its capabilities.

Stable and highly available

Automatic failover and stable backup routing maintain availability when a primary route is down, keeping production steady.

API Reference

Complete API call examples and parameter descriptions

Endpoint

https://api.velokey.ai/v1/messages

Authentication

Bearer YOUR_API_KEY

Request Example

curl https://api.velokey.ai/v1/messages \
  -X POST \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-fable-5",
    "messages": [{"role": "user", "content": "Hello!"}],
    "temperature": 0.7
  }'

Response Example

{
  "id": "req_abc123",
  "model": "claude-fable-5",
  "created": 1234567890,
  "data": { ... }
}

Claude Fable 5 API FAQ

What is Claude Fable 5?

Claude Fable 5 is Anthropic's Mythos-class frontier model — the safeguarded version made safe for general use. It reaches state of the art on nearly all tested AI capability benchmarks, with standout strength in software engineering, knowledge work, vision, and scientific research.

What does 'safeguarded' mean in practice?

It is the safeguarded release made safe for general use. On high-risk requests it transparently falls back to Opus 4.8, which happens in fewer than 5% of sessions, so everyday development and knowledge work run without interruption.

How strong is it at software engineering?

It compresses months of engineering into days. As one example, Stripe completed a 50-million-line Ruby migration in a single day, sustaining focus across a very large codebase.

What can it do with vision and long-horizon tasks?

It extracts precise numbers from scientific figures, rebuilds web apps from screenshots alone, and completed Pokémon FireRed from raw screenshots. With file-based memory in Slay the Spire it improved 3x more than Opus 4.8, reaching the final act 3x more often.

How is it billed on Velokey?

Claude Fable 5 is priced at $10 per 1M input tokens and $50 per 1M output tokens — roughly half the price of Claude Mythos Preview. On Velokey you pay a discount on top of official pricing, billed by input and output tokens, with credits managed centrally in your account.

Start building with Claude Fable 5 today

Use one API key to access low-cost, stable AI models through Velokey.

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