Claude Fable 5 is on Cencori

Claude Fable 5 is live on Cencori.

Anthropic just shipped its most capable model yet. Fable 5 is the generally available release of their Mythos-class architecture—state-of-the-art on nearly every tested benchmark, with exceptional performance in software engineering, knowledge work, scientific research, and vision.

As of today, you can target claude-fable-5 across the entire Cencori stack.

What Makes Fable 5 Different

1. Mythos-Class Architecture

This isn't an incremental update. Fable 5 is built on Anthropic's new Mythos architecture—the same foundation behind the restricted Claude Mythos 5 (available only through the invitation-only Project Glasswing program). Fable 5 brings that same raw capability to general availability, with production-ready safety guardrails baked in.

2. Adaptive Thinking (Always On)

Unlike previous Claude models where extended thinking was opt-in, Fable 5 features Adaptive Thinking as a permanent capability. The model dynamically adjusts its reasoning depth based on the complexity of each query—burning more tokens on hard problems, staying lean on simple ones.

3. Benchmark Dominance

The numbers speak for themselves. Fable 5 leads on agentic coding, knowledge work, spatial reasoning, multidisciplinary reasoning, and vision tasks. The longer and more complex the task, the larger Fable 5's lead over competing models.

4. Built-In Safeguards

Anthropic has been transparent about the tradeoffs: Fable 5's capabilities in areas like cybersecurity could be misused. Queries on a narrow range of sensitive topics will fall back to Opus 4.8 automatically. Users are notified when this happens—and it occurs in less than 5% of sessions.

Pricing & Specs

Using Fable 5 in Cencori

We've updated our provider config and model catalog. You can use it today via the SDK, REST API, or by selecting it in your Project Dashboard.

SDK Example

import { cencori } from '@cencori/sdk';
 
const response = await cencori.chat.create({
  model: 'claude-fable-5',
  messages: [
    {
      role: 'user',
      content: 'Audit this codebase for security vulnerabilities and generate a detailed report with severity ratings.'
    }
  ]
});

REST API

curl https://api.cencori.com/v1/chat/completions \
  -H "Authorization: Bearer $CENCORI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-fable-5",
    "messages": [{"role": "user", "content": "Hello from Fable 5"}]
  }'

Where It Fits

Fable 5 sits at the top of the Claude lineup. For production workloads where cost matters more than peak capability, Opus 4.8 ($5/$25 per MTok) and Sonnet 4.6 ($3/$15 per MTok) remain excellent choices—and both are available through Cencori.

For the hardest problems—deep research, complex multi-file refactors, autonomous agent loops—Fable 5 is the new ceiling.

Claude Fable 5 is available now for all Cencori customers. Check your Model Catalog to see it in action.