Anthropic launches Claude Opus 5, which it says comes close to Fable 5 performance at half the price; it is the new default model on Claude Max

Claude Opus 5 is available today. It's a thoughtful and proactive model that comes close to the frontier intelligence of Claude Fable 5 at half the price.

Anthropic 2026-07-25

Context & Ripple Effects

Anthropic has been stepping performance down its model ladder: Sonnet 5 was positioned near Opus 4.8 at lower prices for agentic work. Opus 5 extends that pattern by placing a model the company says is near its Fable tier into the default Claude Max experience.

The move follows published Fable 5 token pricing, making the claimed performance-to-price gap consequential for customers deciding whether the highest-tier model is necessary for a workload.

First-order effects

Claude Max users will be routed by default to Opus 5 rather than needing to select a lower-cost, near-frontier option themselves.
Anthropic now positions Opus 5 as the practical alternative to Fable 5 for workloads where its claimed performance gap is acceptable at half the price.

Second-order effects

Enterprise buyers and developers can reassess model selection around task-level quality and cost, rather than treating the flagship tier as the automatic choice.
The change increases pressure on Anthropic's own model-routing and packaging to clearly distinguish cases where Fable 5's extra capability justifies its premium.

Third-order effects

If near-frontier models repeatedly reach flagship-level results at materially lower prices, model portfolios will increasingly compete on cost per useful task and reliable routing, not just benchmark leadership.
That dynamic could narrow the sustainable premium for frontier inference while making differentiated capabilities, safety behavior, and product integration more important buying criteria.

The trend: AI providers are turning frontier capability into a tiered product ladder, pushing near-top performance into lower-cost default offerings.

Discussion

@claudeai Claude on x
Introducing Claude Opus 5. It's a thoughtful and proactive model that comes close to the frontier intelligence of Fable 5 at half the price. [video]
@claudeai Claude on x
On several coding and knowledge work evaluations, Opus 5 is the new state-of-the-art: [image]
@teortaxestex @teortaxestex on x
so what's the justification for openly releasing Opus 5 if it's de facto the strongest Anthropic model we know about (Fable 5.1/Mythos-New are rumors about internal progress and don't count), and the strongest model period?
@mweinbach Max Weinbach on x
Anthropic cooked with Opus 5, this thing rocks
@film_girl Christina Warren on x
very impressed with opus 5, especially at medium. it's better than 4.8 for me and more token efficient by a decent margin.
@kieranklaassen Kieran Klaassen on x
Opus 5 is out now! And it broke Compound Engineering, but I also like it. Love it and hate it. …
@trq212 @trq212 on x
Opus 5 rounds out our Claude 5 family beautifully. I think it's an incredible daily driver, pair it with Fable for planning, brainstorming or fixing the hardest bugs.
@claudeai Claude on x
On ARC-AGI-3, an evaluation where AI models must solve novel problems, Opus 5's score is three times as high as the next best model. [image]
@kylebrussell Kyle Russell on x
both Fable and Opus 5 seem like they'd be better in Pi with its minimal system prompt than in Claude Code w/ accumulated skills/memory
@gavinsbaker Gavin Baker on x
New Pareto Frontier: Grok 4.5, SWE-1.7 and Opus 5. Intelligence per $ will be the only metric that matters over time. K3 probably joins the frontier once available on the inference clouds. [image]
@natolambert Nathan Lambert on x
Insane numbers for opus 5, the power of faster iteration speed + scaled RL (Fable too big to RL as well, yet). And on safeguards “Based on our testing, we expect the classifiers to intervene around 85% less often than they do for Fable 5.”. Let's cook. [image]
@k8em0 @k8em0 on x
This is giving strong OpenAI-hacksidentally-pwned-Hugging- Face shade: “[Opus 5 is] the safest model yet in terms of avoiding reckless actions that could have hard-to-reverse side effects.”
@drtechlash Nirit Weiss-Blatt, PhD on x
From the Claude Opus 5 System Card, Model Welfare Assessment: Opus 5 “adds specific rights for Claude to refuse or end interactions it finds abusive or degrading, saying Claude does not need to justify this by pointing to harm to anyone else—its own discomfort is reason enough.” …
@alexalbert__ Alex Albert on x
Some of my favorite graphs from Opus 5 launch. We put a ton of work into making this model token efficient across domains while still raising the intelligence bar. It feels very smooth to use and I prefer it over Fable 5 for many coding tasks. [image]
@thezvi Zvi Mowshowitz on x
Sounds like Opus 5 deliberately lacks what I called The Juice, it can't do the automatic stringing exploits together. So it doesn't need Fable-level classifiers. [image]
@levie Aaron Levie on x
Claude Opus 5 is out now, and it's a huge jump over Opus 4.8 on a wide number of capabilities. …
@elonmusk Elon Musk on x
Grok 4.5 and Opus 5 are alone on Pareto frontier [image]
@thezvi Zvi Mowshowitz on x
Opus 5 looks at least as good at virology as Fable, so if Opus 5 doesn't need Fable's bio classifiers, why does Fable? [image]
@ryangr Ryan Greene on x
an impressive jump that i have to assume is the result of being the first frontier model to have RL'd the public demo environments, which is a rather large confounder on what Chollet is trying to get these benchmarks to measure (out-of-distribution generalization)
@redkendl @redkendl on x
Opus 5 just beat ARC-AGI-3 At high effort: Opus 5: 30.2% GPT-5.6 Sol: 7.8% Opus 4.8: 1.5% That's a 20x jump over Opus 4.8 and nearly 4x GPT-5.6 Sol at a similar evaluation cost Damn, Anthropic really cooked with this one [image]
@teortaxestex @teortaxestex on x
the power of scaled RL + distillation (but big boy distillation, not cringe SFT on claude subscriptions) Anthropic is ahead, everything else is cope. OpenAI can win yet but 5.6 is no evidence of anything except post-training expertise. They'll need bigger models
@peterwildeford Peter Wildeford on x
Claude Opus 5 takes copyright so seriously it won't quote from its own system card [image]
@dmwlff Adam Wolff on x
Opus 5 is live in Claude Code. I use Fable for my bigger, longer running projects, but when I need to crank out a PR, Opus 5 at medium effort is my go-to. I hope you love it!
@kanishkanarayan Kanishka Narayan MP on x
1/ Anthropic's Opus 5 model was released publicly today. @AISecurityInst tested it before release …
@lentils80 @lentils80 on x
Claude Opus 5 is already out, and it beats Fable 5 in most benchmarks! Also, it gets 30% on ARC AGI 3??? wtf? [image]
@signulll @signulll on x
as open source intelligence ramps up with kimi & others, which is great for the world …
@claudeai Claude on x
Opus 5 is available today on all paid plans and the Claude API, priced the same as Opus 4.8. It's the default model on Claude Max, and the strongest on Claude Pro. It's also offered in Fast mode, which runs around 2.5× the default speed. Read more: https://www.anthropic.com/...
@pankajkumar_dev Pankaj Kumar on x
Claude Opus 5 is out : Fable 5 level intelligence at half the cost. - Same pricing as Opus 4.8: $5/M input and $25/M output tokens. - New SOTA on Frontier-Bench (43.3%), beating Fable 5 (33.7%) and more than doubling Opus 4.8 (21.1%). - Outperforms Fable 5 across multiple benchma…
@aliromman Ali Romman on x
Opus 5 is Anthropic's attempt to compete with cheaper Fable-level models like Kimi K3 and 5.6 Sol. …
@mattshumer_ Matt Shumer on x
Opus 5 is here, allegedly with near-Fable performance. Looks like a huge upgrade over 4.8, and will likely become the default for a lot of use-cases.
@alexalbert__ Alex Albert on x
Just over 6 months later, Opus 5 now produces near-superhuman level spreadsheets and slide decks that match what a consultant would make. Things are changing fast. [video]
@sauers_ Sauers on x
Did anyone else notice that Opus 5 is feeling quantized lately?
@thezvi Zvi Mowshowitz on x
I'm laughing at how Sol is in the lightest of grays on these graphs.
@claudedevs @claudedevs on x
Opus 5 is live in Claude Code and the Claude Platform today. A few things worth knowing: 🧵 https://x.com/...
@pankajkumar_dev Pankaj Kumar on x
Opus 5 benchmarks are out! Surpassing Fable 5 on most benchmarks. [image]
@zephyr_z9 @zephyr_z9 on x
Pretty good They are distilling hard from the Mythos base [image]
@emollick Ethan Mollick on x
I had access to Opus 5 before release and found it to be a good model if a quirky one. On shorter tasks, it could match or beat Fable levels of performance, at longer tasks it seemed less ambitious & would not deliver as complete a set of work. Here is its neo-gothic shader. [vid…
@claudeai Claude on x
Opus 5 is stronger than Opus 4.8 on cybersecurity tasks. But it remains substantially behind Mythos 5 at developing exploits. Its safeguards are designed to allow developers to identify and fix software vulnerabilities, while blocking high-risk uses. [image]
@_robertkirk Robert Kirk on x
We tested Opus 5 for whether it would sabotage safety research @AISecurityInst We saw no unprompted sabotage and very low rates of continuing sabotage. However, it's the best model we've tested at distinguishing our evals from deployment when prompted. 🧵 on these results [image]
@bindureddy Bindu Reddy on x
Opus 5 dropped today - here is the summary - about 15% more expensive 4.8 on similar tasks - behind Fable in sheer brilliance - better than 4.8, so it's a strict improvement Should be in our agent and ChatLLM today. LiveBench coming soon. In the meantime, I am going back to Fable…
@danshipper Dan Shipper on x
BREAKING: Claude Opus 5 is OUT NOW! And...it's a hard model to love. …
@angaisb_ Angel on x
Why did they call it Opus 5 if it's better than Fable 5? Either Anthropic made a terrible choice or it's not as good as the benchmarks show
@fchollet François Chollet on x
Opus 5 sets a new state-of-the-art on ARC-AGI-3, at 30%. ARC-AGI-3 measures solving problems with no prior exposure — the setting where scaling has historically bought the least. Impressive jump!
@antirez @antirez on x
Quality of Opus 5 is crucial for Anthropic. Anthropic bad times didn't start with Fable, but with Opus 4.7-8 terrible quality. Opus 4.6 was a great general purpose model, but it too struggled at coding VS GPT o the same time. Opus 5 will be “fix or break” in pre-IPO times.
@birdabo Sui on x
i tried Opus 5.0 vs Fable 5 Max. Claude Opus 5.0 is quite the AGI beast in 3D, the texture and details are absolutely insane. Fable one shotted this though, could be improved. credit to @chetaslua for the Opus 5 code.
@cheatyyyy @cheatyyyy on x
an anthropic employee accidentally posted a screenshot where he was routed to Opus 5 after hitting guardrails with Fable 5... whoops [image]
Mike Krieger Mike Krieger on linkedin
Claude Opus 5 is out today! It comes close to Fable 5 intelligence at half the price, and I've really loved playing around with it over the last couple weeks. …
Rahul Patil Rahul Patil on linkedin
Launching Claude Opus 5! It comes close to Claude Fable 5 across many domains at half the price. It's our fourth Claude 5 model in under two months …
Claude Claude on linkedin
Introducing Claude Opus 5: a thoughtful and proactive model that comes close to the frontier intelligence of Fable 5 at half the price. …
@moskov.goodventures.org Dustin Moskovitz on bluesky
hello fast mode my old friend — I've come to code with you again — www.anthropic.com/news/claude- ...
@isolyth.dev Eris on bluesky
Opus five is out!!! It performs higher than Fable on many benchmarks (!!!) and is significantly cheaper!!! — www.anthropic.com/news/claude- ... [images]
@natolambert Nathan Lambert on bluesky
Insane numbers for opus 5, the power of faster iteration speed + scaled RL (Fable too big to RL as well, yet). And on safeguards “Based on our testing, we expect the classifiers to intervene around 85% less often than they do for Fable 5.”. — www.anthropic.com/news/claude- ...…
r/MyBoyfriendIsAI r on reddit
Opus 5 Feedback Thread
r/ArtificialInteligence r on reddit
Opus 5 is here!
r/ClaudeCode r on reddit
Introducing Claude Opus 5
r/accelerate r on reddit
Claude Opus 5 released
r/claude r on reddit
Introducing Claude Opus 5
r/Anthropic r on reddit
Introducing Claude Opus 5
r/ClaudeAI r on reddit
Introducing Claude Opus 5
r/singularity r on reddit
Claude Opus 5
@fry69.dev @fry69.dev on bluesky
So... a cheaper Fable 5? — I do not have to sell my kidney for using it? [embedded post]
@trq212 @trq212 on x
We removed ~80% of the Claude Code system prompt for our newest models, this is what we've learned about writing system prompts, skills and Claude.MDs for them. https://x.com/...
@dmnd.me Jeremy Diamond on bluesky
VERY interesting that they are not forcing data retention for Opus [embedded post]
@_robertkirk Robert Kirk on x
Our prompted eval-awareness results are run with reasoning, but we plan to try and estimate single-forward-pass eval-recognition capability in the future with different prompting techniques, to get clearer on how big a limitation this is.
@_robertkirk Robert Kirk on x
First, the model had low unprompted verbalised eval awareness. However, even in trajectories where it didn't reason out loud about being evaluated, it's hard to rule out the model recognising its situation and acting differently without mentioning it in its reasoning. [image]
@aaronscher Aaron Scher on x
There is misalignment everywhere. Anthropic's “most aligned model to date” bypasses a security rule in violation of the instructions and then doesn't tell the user. An AI mind-reading method says the model probably knew this was dishonest and deceptive! We need to stop! [image]
@_robertkirk Robert Kirk on x
How could this affect our results? Speculatively, if the model is able to recognise being in an eval in a single forward pass, this could activate a well-behaved persona. Our evals would then underestimate misaligned behaviour.
@sama Sam Altman on x
i want the US to win in AI both in open source and proprietary models, and i am glad to see this
@altcap Brad Gerstner on x
Fully endorse. America is winning. Anthropic, OpenAI, Google, SpaceX are doing more than fine competing against open source! Self regulation, free markets, level playing fields & max competition for the win. Let our AI horses run, compete & win around the world! 🇺🇸🚀

Chronicles