Anthropic released a new top model this morning, June 9, 2026. It is called Claude Fable 5, it sits in a new tier above Opus, and if you opened Claude Code and typed /model expecting to see it in the list, you got the same thing I did: Opus, Sonnet, Haiku, and no Fable anywhere.
I ran claude update. Already on the latest version (2.1.170 as I write this). Still no Fable in the picker.
This is not a bug and your install is not broken. Here is what's going on and the fix, which takes about five seconds.
What Fable 5 actually is
Quick orientation, because the naming is new. Anthropic announced two models together:
- Claude Fable 5 is the one you can use. It is a Mythos-class model, a capability tier above Opus, wrapped in safety classifiers that make it suitable for general release. Anthropic says it leads on nearly every benchmark they tested, with software engineering and scientific research called out specifically.
- Claude Mythos 5 is the same underlying model with the safeguards lifted. It is restricted to approved users, currently cybersecurity professionals through Anthropic's trusted access program, with biomedical researchers next.
The practical difference for you and me: Fable 5 is generally available on the Claude API, Amazon Bedrock, Vertex AI, and Microsoft Foundry. When you send Fable 5 a query on one of the gated topics, the response comes from Claude Opus 4.8 instead. For normal business and coding work you will never notice. You are getting the stronger model with a fallback on a narrow set of subjects.
Pricing is $10 per million input tokens and $50 per million output. For reference, that is double Opus 4.8's standard rate of $5 and $25, and exactly equal to Opus 4.8's fast-mode rate. More on whether that trade is worth it below.
Why /model doesn't list it
The /model picker in Claude Code is not a live query against Anthropic's model catalog. It is a list baked into the CLI build you have installed. Your build shipped before Fable 5 existed, so the picker has never heard of it. claude update can't help on release day because there is no newer build to update to yet. The picker will catch up when the next CLI release ships.
The part most people miss: the picker is just a convenience menu. Claude Code will happily use any valid model ID you hand it directly.
The fix: type the ID
Inside any session, give /model the full model ID as an argument instead of picking from the menu:
/model claude-fable-5
That's it. Claude Code confirms with "Set model to claude-fable-5 and saved as your default for new sessions." You are now running Fable 5, today, on a CLI build that predates the model.
Three other routes to the same place, depending on how you like to work:
At launch, with a flag:
claude --model claude-fable-5
As an environment variable (PowerShell shown; add to your profile to persist):
$env:ANTHROPIC_MODEL = "claude-fable-5"
Pinned in settings.json (~/.claude/settings.json), which is the right answer if you want it durable across machines and sessions:
{ "model": "claude-fable-5" }
One prerequisite none of these can route around: your account has to have Fable 5 access provisioned. If you type the ID and get a model-not-found or permission error, that is an access problem on your plan or org, not a configuration problem on your machine. Nothing to fix locally; check your plan tier or ask your admin.
How to confirm it took
Type /model again with no argument. The status line shows the active model. You can also just ask the session what model it is, though the honest check is the status line, since a model's self-report can lag what the harness actually routed.
If you pinned it as default and later want back on Opus 4.8, same trick in reverse: /model opus or pick from the menu as usual.
Should you actually switch?
The under-$100 stack logic applies here the same way it applies everywhere else: pay for capability where capability is the bottleneck, and nowhere else.
At $10/$50, Fable 5 costs the same as running Opus 4.8 in fast mode and twice standard Opus. If your sessions are mostly routine, glue work, file edits, short questions, the honest answer is that Opus 4.8 was not your bottleneck and doubling your token rate buys you little. Keep your default where it is and reach for Fable when the task is genuinely hard: a thorny architecture decision, a research synthesis, a debugging session that has eaten an afternoon.
The pattern I would actually run: leave the cheap model as your session default, and switch with /model claude-fable-5 for the single hard task, then switch back. The five-second command makes per-task routing practical in a way it wasn't when changing models meant editing config files. If you have been following the routing approach from my model routing post, Fable 5 slots in as a new top rung on the ladder, not a replacement for the whole ladder.
And before you move any real workload onto it, run your own validation pass rather than trusting launch-day benchmarks. The checklist in validate a model before you upgrade was written for exactly this morning.
One more honest note: a model released today is past the knowledge cutoff of every assistant currently running, including the one helping you set it up. When I first asked about Fable 5 this morning, my own session confidently told me no such model existed, then checked the announcement and corrected itself. Verify against the source, not the model's memory. That habit costs nothing and catches a lot.
If you are building a business on top of tools like this rather than just using them, the playbook for shipping something small and paid on a stack this cheap is the whole subject of The $97 Launch.
Fact-check notes and sources
- Claude Fable 5 and Claude Mythos 5 announcement, June 9, 2026: anthropic.com/news/claude-fable-5-mythos-5. Model tier, safeguard design, Opus 4.8 fallback behavior, and availability claims are from this page.
- Pricing of $10 per million input tokens and $50 per million output tokens for both models: same announcement page.
- API model ID
claude-fable-5: stated on the announcement page ("use claude-fable-5 via the Claude API") and confirmed working in Claude Code 2.1.170 by the author on June 9, 2026. - General availability on the Claude API, Amazon Bedrock, Vertex AI, and Microsoft Foundry; Mythos 5 limited availability through Project Glasswing: Anthropic announcement and same-day coverage by TechCrunch and NBC News.
- Opus 4.8 standard pricing of $5/$25 and fast-mode pricing of $10/$50 per million tokens: Anthropic Opus 4.8 release materials, May 2026.
- The
/model <full-id>behavior and "saved as your default for new sessions" confirmation: observed directly in Claude Code 2.1.170 on Windows, June 9, 2026.
