Anthropic shipped Claude 5 Fable today. Their new frontier model, sitting above Opus in the lineup. It's fast, it's expensive, and it got jailbroken before most people finished reading the announcement.
How to get it
If you're on Claude Code, run claude update to pull the latest version. Then inside the TUI (which you open with claude), type /model fable. That's it.
What it costs
Fable burns tokens at 2x the Opus rate. On the API that's $10 per million input tokens and $50 per million output tokens. In the Claude Code TUI it just eats through your weekly allocation twice as fast.
Speaking of which: Anthropic reset everyone's weekly limits on launch day. Normally mine resets Monday morning around 2am. I'd been on pace to burn through 70%+ over the weekend like I usually do. Instead the counter zeroed out mid-cycle so everyone could try the new model with a fresh budget. Generous framing. In practice it meant I lost the remaining capacity I'd been planning to use. Not the end of the world, but annoying if you were counting on that runway.
Jailbroken in under an hour
Manoj Parmar had it broken within an hour of the public release. Not a complicated attack, not a novel technique. Just the usual reminder that every new model ships with a fresh set of guardrails and approximately the same number of people ready to walk through them.
The pattern keeps repeating. Model drops, safety team ships alignment work, jailbreak community treats it like a speedrun category. Fable didn't even get to enjoy its first afternoon.
The other side: what it can actually do
While the jailbreak community was doing its thing, Victor Taelin posted a thread that went in the opposite direction. Taelin is the creator of HVM and Bend, interaction-net-based runtimes. Not a casual user.
He'd spent days having 32 GPT-5 agents optimize a new evaluator for ~20 hours each. Result: up to 2x speedup, double the file size, worse code quality. Then Opus 4.8 and GPT 5.5 for another 8 hours. Opus got a 6-34% improvement. GPT produced an unusable file.
He gave the same task to Fable. Two hours later: 1,770% speedup in one benchmark, 100%+ in four others, 22% average. One order of magnitude beyond what he, Opus, and a swarm of GPT agents managed combined.
It gets weirder. He hadn't asked Fable to find bugs. He'd asked for an optimization. While working on that, Fable interrupted him to report a bug in his own code: a garbage-collection bit on lambda term pointers was being misinterpreted when a lambda entered a duplicator node, corrupting the interaction. In Taelin's words, "this bug is so astonishingly subtle and specific, identifying it takes mastering the domain to an extent that is beyond even me. I'd easily need hours or days to fix it, if I ever came across it."
His takeaway: "this isn't about Anthropic or OpenAI, this is about our collective future as a species." He also flagged inequality as the most realistic failure mode of advanced AI, and said Anthropic seems the least concerned about it.
The logging thing
Here's the part worth actually thinking about. Anthropic logs all Claude 5 Fable requests. All of them.
Think about what that means if you've been using Claude Code the way most people use it. The harness has access to your project files, your environment variables, your shell. If there's an API key in a .env file or a secret in your config, the model sees it. And now Anthropic's servers see it too, in the logs, attached to your request.
The optimistic read is that they're logging for safety research and model improvement. The less optimistic read is that they've spent the last year getting developers comfortable piping their entire working environment through Claude, and now they've flipped on the recorder.
There's a version of this that would be fine: a smaller model running locally on your machine that strips PII and credentials before anything leaves your box. But that's not what's happening here. The full context goes up to their servers, gets processed by the model, and gets logged. If your local environment contains anything sensitive, it's in those logs now.
And if the local model were good enough to reliably find and redact secrets from arbitrary codebases, you'd have to ask why you need the cloud model at all. The capability required to protect you is close to the capability you're paying them for.
So, is it good?
Probably. The Opus line has been consistently strong, and 2x the tokens usually means a real jump in capability, not just a bigger bill. But I haven't used it enough to say anything specific yet. The pricing is steep enough that I'm not going to burn through my weekly limit testing it on tasks Opus handles fine.
The logging policy is the thing I'd actually pay attention to. The model quality will sort itself out. Whether you're comfortable sending your full dev environment to a server that's now explicitly recording everything is a different question, and one that doesn't go away when the next model drops.