Claude Fable 5 Is Here:
Anthropic's Most Capable Model, Now on Secret Chat

Published July 3, 2026

We have some news for everyone who picks Claude for the hard questions: Claude Fable 5 is now available on Secret Chat. It is Anthropic's most intelligent generally available model — the first release in the new Claude 5 family — and you can now use it directly from the same private workspace where you already chat with GPT, Claude, Gemini, Grok, and Perplexity.

One honest note up front: Fable is expensive. Anthropic prices it at twice the rate of Claude Opus, so we made a deliberate decision not to wire it into our Smart Agentic Claude router — the automatic mode still relies on Opus, which remains an outstanding model at half the cost. Instead, Claude Fable 5 is available as a manual mode you choose yourself, for the moments when you genuinely want the strongest reasoning Anthropic has to offer. This article explains what Fable is, where it came from, how to use it on Secret Chat, and when it is (and isn't) worth reaching for.

What Is Claude Fable 5?

Claude Fable 5 is the first model in Anthropic's Claude 5 generation, released in mid-2026. It is also the first model in a new class that Anthropic positions above the Opus tier — until now, "Opus" was always the top of the Claude lineup. Fable is built for the most demanding work: deep multi-step reasoning, long-horizon agentic tasks, complex analysis, and problems where a model has to hold a huge amount of context in its head at once.

A few characteristics that set it apart:

• Reasoning is always on. Unlike earlier Claude models, where extended thinking was optional, Fable 5 always reasons before it answers. It decides on its own how deeply to think about each request — a quick question gets a quick answer, a hard one gets genuine deliberation.
• A one-million-token context window with up to 128K tokens of output per response, so it can digest very long documents and produce very long, structured answers.
• Top-tier capability. Anthropic describes it as its most capable widely released model, ahead of Claude Opus 4.8 on the hardest reasoning and agentic benchmarks.

A Short History: Mythos, Fable, and the Tier Above Opus

The Fable story is a little unusual, and worth telling. For most of Claude's history, Anthropic's lineup was a simple ladder: Haiku (fast and cheap), Sonnet (balanced), Opus (most capable). In 2026, Anthropic began previewing something above that ladder — an invitation-only research model known as Claude Mythos Preview, available only to a small set of partners.

That preview grew into two sibling releases that share the same underlying model:

• Claude Fable 5 — the generally available version, which ships with additional safety measures around dual-use capabilities (for example, it declines certain sensitive cybersecurity and biology requests).
• Claude Mythos 5 — the same model without those extra measures, offered only to a limited set of approved organizations through Anthropic's access program.

In other words, Fable 5 is the version of Anthropic's frontier model that the rest of the world gets to use — and that is the one now available on Secret Chat. If you want the deeper technical background, Anthropic's own announcement is at anthropic.com/news/claude-fable-5-mythos-5.

The Catch: Fable Costs Twice as Much as Opus

Frontier capability comes with a frontier price. On Anthropic's API, Claude Fable 5 costs $10 per million input tokens and $50 per million output tokens — exactly double Claude Opus 4.8, which sits at $5 and $25. And because Fable always reasons before answering, it also tends to generate more (billed) thinking tokens per reply than a model that answers directly.

That pricing gap is the whole reason for the design decision described next.

Why Smart Agentic Claude Still Runs on Opus

If you use Claude on Secret Chat in its default Smart Agentic mode, an intelligent router looks at each of your messages and picks the right tool for the job — a fast model for casual chat, web search when you need fresh information, deep research for involved questions, and the strongest reasoning model for genuinely hard problems. The best model in that lineup is, and remains, Claude Opus.

We deliberately did not put Fable into that automatic rotation, for a simple reason: the router fires on every conversation, including plenty of messages that don't need frontier-level reasoning. Routing those through a model that costs twice as much would quietly double the cost of everyday chats without making them noticeably better. Opus 4.8 is an exceptional model — for the vast majority of prompts the difference between it and Fable is small, while the price difference is not.

So the split works like this: Smart Agentic Claude keeps Opus as its top model, and Claude Fable 5 is there as an explicit, manual choice when you decide a particular task deserves it. You stay in control of when the premium model runs.

How to Use Claude Fable 5 on Secret Chat

Using Fable takes two clicks in the Secret Chat app:

1. Open the Secret Chat app and select the Claude model in the model picker, as usual.
2. In the mode selector next to the message box — where you normally see options like Smart Agentic, Fast Chat, Web Search, and Research — choose "Claude Fable 5" (the mode with the star icon).

From that point on, your messages in the conversation go straight to Claude Fable 5. Switch the mode back to Smart Agentic at any time and the router (with Opus at the top) takes over again.

One more detail worth knowing: on Secret Chat, Fable is web-grounded. It can search the web and read pages while composing its answer, so its deep reasoning is combined with current information rather than being limited to what the model learned in training.

When Is Fable Worth It?

Since Fable answers cost more of your credits than Opus answers, it makes sense to be intentional about when you use it. A practical rule of thumb:

• Reach for Claude Fable 5 when the task is genuinely hard: intricate multi-step reasoning, dense legal or technical documents, tricky architectural or mathematical problems, long analyses where earlier models start to lose the thread, or anything where you'd happily pay a bit more for the best possible answer.
• Stay on Smart Agentic Claude for everything else: everyday questions, drafting and editing, brainstorming, coding help, research with sources. The router already escalates to Opus when a task is demanding, and for most work that is exactly the right level.

A nice workflow many of our users already apply with other models: ask Smart Agentic Claude first, and if the answer to a truly hard question feels short of the mark, switch the same conversation to the Claude Fable 5 mode and ask again. Comparing the two responses side by side tells you quickly whether the premium model earns its price for your kind of work.

Private by Design, Whatever Model You Pick

Everything else about Secret Chat stays the same, and it applies to Fable exactly as it does to every other model. Secret Chat is a private gateway between you and the AI providers: your prompts are forwarded through our proxy, so you don't need an account with Anthropic and your identity isn't attached to your requests on the provider's side. Your conversation history is stored locally in your own browser, not on our servers — we couldn't read your chat archive even if we wanted to. And you can pay with crypto if you prefer not to link a card to your AI usage.

That combination matters more, not less, with a model like Fable. The whole point of a frontier reasoning model is that you hand it your hardest, most substantive problems — which are often exactly the things you least want sitting in someone else's logs under your name. If you want the longer story on how our gateway approach compares to running models yourself, we wrote it up in Secure AI Gateway Explained.

Conclusion

Claude Fable 5 is the most capable model Anthropic has ever made generally available, and it is now one click away on Secret Chat. We kept it out of the automatic Smart Agentic rotation because it costs twice as much as Opus and most conversations simply don't need it — but when yours does, select the Claude model, switch the mode to "Claude Fable 5", and give it your hardest problem.

Try it today at Secret Chat — privately, with your history in your own browser, and with the full multi-model lineup at your fingertips.

Frequently Asked Questions

1. What is Claude Fable 5?

   Claude Fable 5 is the first model in Anthropic's Claude 5 family and its most intelligent generally available model — a new tier positioned above Claude Opus. It always reasons before answering, supports a one-million-token context window, and is built for the most demanding reasoning and long-horizon tasks.

2. How do I use Claude Fable 5 on Secret Chat?

   Open the Secret Chat app, select the Claude model, and pick "Claude Fable 5" in the mode selector next to the message box. To go back to automatic routing, switch the mode back to Smart Agentic.

3. Why isn't Fable part of Smart Agentic Claude?

   Because of cost. Anthropic prices Fable 5 at double the rate of Claude Opus 4.8 ($10/$50 versus $5/$25 per million tokens), and the Smart Agentic router runs on every conversation. Keeping Opus as the router's top model keeps everyday chats affordable, while Fable stays available as an explicit manual choice.

4. Is Claude Fable 5 better than Claude Opus?

   On the hardest reasoning and agentic tasks, yes — it is Anthropic's most capable generally available model. For typical everyday prompts the difference is much smaller, which is exactly why we recommend Smart Agentic Claude (with Opus) as the default and Fable as the deliberate upgrade for genuinely difficult problems.

5. What is the difference between Claude Fable 5 and Claude Mythos 5?

   They share the same underlying model. Fable 5 is the generally available version with additional safety measures around dual-use capabilities; Mythos 5 is offered without those measures to a limited set of organizations approved by Anthropic. Secret Chat offers Claude Fable 5.

6. Can Claude Fable 5 search the web on Secret Chat?

   Yes. On Secret Chat, Fable is web-grounded: it can search the web and read pages while working on your request, so its answers combine deep reasoning with current information.