AI / Claude Models Basics Interview Questions
What is Claude Fable 5 and what makes it different from Claude Opus 4.8?
Claude Fable 5 (claude-fable-5) is Anthropic's most capable widely-released model as of mid-2026, positioned above the Opus tier. It is designed for long-running agents, frontier intelligence tasks, and complex enterprise work.
| Feature | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|
| API ID | claude-fable-5 | claude-opus-4-8 |
| Context window | 1 million tokens | 1 million tokens |
| Max output tokens | 128,000 | 128,000 |
| Thinking | Always-on adaptive thinking | Adaptive thinking (configurable) |
| Pricing (input) | $10 / MTok | $5 / MTok |
| Pricing (output) | $50 / MTok | $25 / MTok |
| Data retention | 30-day minimum (no ZDR) | Available under ZDR |
| Availability | GA on Claude API, Bedrock, Vertex, Foundry | GA on all platforms |
Key differences to be aware of:
- Fable 5 is priced at 2× Opus 4.8 for both input and output tokens
- Fable 5 requires a minimum 30-day data retention period and is not available under zero data retention (ZDR) arrangements — organisations with ZDR requirements should use Opus 4.8
- Fable 5 uses always-on adaptive thinking, meaning it automatically applies extended reasoning to every request
- Migration from Opus 4.8 to Fable 5 is described as mostly drop-in since both use the same Messages API and tool use patterns
Invest now in Acorns!!! 🚀
Join Acorns and get your $5 bonus!
Acorns is a micro-investing app that automatically invests your "spare change" from daily purchases into diversified, expert-built portfolios of ETFs. It is designed for beginners, allowing you to start investing with as little as $5. The service automates saving and investing. Disclosure: I may receive a referral bonus.
Invest now!!! Get Free equity stock (US, UK only)!
Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.
The Robinhood app makes it easy to trade stocks, crypto and more.
Webull! Receive free stock by signing up using the link: Webull signup.
More Related questions...
