Letter: the US lifts its block on Mythos 5, allowing Anthropic to release it to more than 100 US institutions; sources: talks about Fable 5 are ongoing

THE SCOOP — The US government Friday lifted its block on Anthropic's powerful Claude Mythos 5 AI model, allowing the company to release …

Semafor 2026-06-27

Context & Ripple Effects

Related coverage shows the decision evolving from a block on Anthropic’s Mythos 5 to permission for redeployment at critical-infrastructure operators and, subsequently, the lifting of export controls on both Mythos 5 and Fable 5.

The follow-up reporting ties the access restoration to Anthropic’s commitment to proactively detect and address security risks, making the episode a test of whether technical safeguards can unlock deployment of highly capable models.

First-order effects

Anthropic can resume Mythos 5 distribution to more than 100 US institutions, restoring access for organizations that had been unable to use the model.
The government’s decision creates a clearer path for Anthropic to put Mythos 5 into critical-infrastructure settings, while Fable 5 remained subject to separate negotiations at this point.

Second-order effects

Institutional customers can plan around renewed access, but the reported security-risk commitments make safeguards and monitoring part of the practical conditions of deployment.
Other frontier-model providers serving sensitive US customers face stronger pressure to demonstrate comparable controls if access restrictions become tied to verifiable risk-management measures.

Third-order effects

The episode points toward a conditional-access model for advanced AI: restrictions may be eased or reimposed based on providers’ ability to identify and mitigate security risks, rather than through a simple permanent approval or ban.
If that approach persists, government clearance and ongoing safety operations could become a meaningful competitive variable in the market for AI deployments in critical sectors.

The trend: Frontier AI deployment is moving toward risk-based government access regimes in which provider safeguards shape who can use advanced models and where.

Discussion

@yonashav Yo Shavit on x
I, for one, welcome our more than 100 US institution overlords
@beffjezos @beffjezos on x
US startups need Fable and 5.6 to stay competitive. We need to accelerate these approval timelines.
@sophiacai99 Sophia Cai on x
🚨Huge thaw in WH-Anthropic relationship tonight as Commerce partially lifts export ban on one of Anthropic's advanced AI models, Mythos 5 ( @semafor had first) - Commerce allowing 100 “trusted partners” including companies and gov agencies to access Mythos 5 - Fable 5 is still ba…
@trungtphan Trung Phan on x
POV: The US government showing Anthropic which 100 companies are now allowed to access the Claude Mythos and Fable models. [video]
@semaforben Ben Smith on x
Mythos is back [image]
@markvalorian Mark Valorian on x
Mythos is back on the market. ~100 handpicked companies and government institutions now have access. No word on fable. [image]
@arthurctellis Arthur Tellis on x
The man, the mythos, the legend
@kevinbankston Kevin Bankston on x
Okayyyy. So... —Why now? —What companies and why? —What if anything has actually changed in terms of cyber risk? —Why not Fable? And finally... —WHY ALWAYS ON FRIDAY AFTERNOONS?!?
@reedalbergotti Reed Albergotti on x
Scoop from @semaforben and me: The Commerce Dept is allowing Mythos back in the market. Limited customers. Still no Fable 5 but that likely comes next.
@kimmonismus @kimmonismus on x
Bloomberg says Commerce Secretary Howard Lutnick is making progress on security concerns that triggered the curbs, according to people familiar with the talks.
@garrytan Garry Tan on x
This is honestly no way to release a model and continued development and release this way is a solid way to salt the ground and kill all innovation by small startups
@valkyrie.hacker.gf Andrea on bluesky
We're getting “Donate to Trump or you'll get Stupid Claude”, aren't we? [embedded post]
@markriedl Mark Riedl on bluesky
No resolution on Fable 5 yet but some US institutions and the us government can use Mythos [embedded post]
@justinhendrix Justin Hendrix on bluesky
“The US government Friday lifted its block on Anthropic's powerful Claude Mythos 5 AI model, allowing the company to release it to more than 100 US institutions, including major companies and government agencies.”
@alondra Alondra Nelson on bluesky
Returning to a Biden administration AI governance and policy posture that this administration described as “hand-wringing about safety,” Semafor notes that “Lutnick's letter marks the beginnings of a new regulatory regime that gives the US government control over the release of f…
r/wallstreetbets r on reddit
Trump admin allows Anthropic to release Mythos AI model to some companies, government agencies
@levie Aaron Levie on x
Step one complete
@andrewcurran_ Andrew Curran on x
Update directly from Anthropic. https://x.com/... [image]
@matthewberman Matthew Berman on x
Please sir may I have some Fable
@jun_song Jun Song on x
Prediction for Anthropic's next move: They will warn that Chinese open-source AI has CCP backdoors and will steal your credit card passwords. In response, the US government will impose strict restrictions on using Chinese open-source AI. And society will start shaming people
@cheyennehaslett Cheyenne Haslett on x
Person familiar with the discussions between the admin and Anthropic says conversations are expected to continue over the weekend on Fable, which was not restored with this latest development. Also says that conversations have been focused not just on resolving this export
@theo @theo on x
It's kind of wild that the two best AI models ever made are being restricted by the country they were built in
@dan_jeffries1 Daniel Jeffries on x
To be very clear, this is how these companies go out of business. Period. You cannot fund 2 billion dollar training runs if you have to beg the government to grant access to customers. The second order effects of this are the economic boom grinding to a halt, investment
@ctrlaltdwayne Dwayne on x
Well, Anthropic got their wish. Government control of powerful AI models. This is going to do wonders for the IPO.
@deryatr_ Derya Unutmaz on x
I am so deeply disappointed by the US gov. It was apparently a mistake to think this administration had a good sense to support American AI models. However, I also put more blame on the cult of Anthropic & Dario Amodei. All that fearmongering both achieved its goal & backfired!
@maxedapps Maximilian on x
Sooo ... we're now entering the worst possible timeline as it seems: Access to the top models a select few, breadcrumbs for the rest. So many interesting ways for China to play this. Go closed source and try collecting money + more data? Play the good guys and keep the models
@matthewberman Matthew Berman on x
Anthropic just struck a deal with the government to allow 100 select companies and governmental agencies use Mythos. The government and anthropic are now deciding who uses frontier intelligence. Hopefully this is just Mythos and not the standard for all frontier models going
@bendifrancesco Ben DiFrancesco on x
The only idea worse than having the government banning models outright is having the government decide which companies do and don't get access to the frontier models.
@alexandertw33ts Alex on x
BREAKING: member of the permanent underclass left SHOCKED after finding out the permanent upperclass is invite only
@pawelhuryn Paweł Huryn on x
I don't buy the safety story. Not from the labs, not from the government. Fable, gone. Mythos, gone. Then all of GPT-5.6, down to Luna, the cheap everyday model for summarizing and drafting. A summarizer is not a cyber weapon. But cheap intelligence is the one thing that lets
@garymarcus Gary Marcus on x
Ladies and gentlemen, I am pleased to announce that staplers & pencil erasers will once again be available for sale to some companies, as well as a few close personal friends and important donors. This is US only. Allies and former allies can suck it. - POTUS
@scaling01 @scaling01 on x
foreign Anthropic employees saved “a license will no longer be required to export, reexport, or in-country transfer [..] the Claude Mythos 5 Model [...] to Anthropic's foreign national employees” please continue vibe-coding with Mythos Andrej [image]
@angaisb_ Angel on x
Anthropic: We will share more details over the next 24 hours (they ignore us for weeks) OpenAI: ok so this model isn't even really out but here's what we're going to do and what we expect to happen, we'll keep you updated. If you have any questions, you can ask Sam
@kimmonismus @kimmonismus on x
About 100 organizations got access to fable 5/mythos 5 again. Department of commerce is slowly lifting the embargo for those models. However, I still think that public access will remain heavily restricted—either with significantly stricter guardrails or a lobotomized model. [ima…
@gfodor @gfodor on x
I hate to break it to everyone, but America First is going to literally be the policy for domestic AI models going forward. Now that Dario woke up the sleeping giant and they realize the lever they have here for US economic dominance you can be certain they will keep smashing it.
@mark_k Mark Kretschmann on x
I'm already a bit tired of the whole US government AI regulation drama. I was considering to write a big post about it, but I don't think I have it in me because everything important has already been said. Let me just emphasize the absolute importance of open source models. Now
@theo @theo on x
What if this was a 5d chess play and Dario did this just to force frontier AI development to slow down?
@sporadica @sporadica on x
this is probably the standard for all frontier models going forward and this will essentially guarantee China wins nice going, Dario + Trump, you traitors
@reed_barnes Reed on x
it's 2027. you take a free-tier public Waymo to the DMV (Department of Model Variance) to do a proof-of-identity check for access to GPT 7.1. the guy at the counter is clearly watching a Mr. Beast video in his AR glasses. “Here for that new model?” he says, barely making eye
@rationalaussie @rationalaussie on x
The idea that a model can be kept behind closed doors at all over any sustained period of time is completely retarded anyway. It's not like nuclear materials. Someone can literally walk out of there with the weights on a hard drive and give it to the world. And that's
@wholemars @wholemars on x
What a dark future. Super-intelligence in the hands of a select few. They can use the latest models to exploit your software, but you're not allowed to use those models to make your software more secure. How utterly dystopian.
@hugolowell Hugo Lowell on x
People involved in deliberations tell me the Trump admin x Anthropic saga is still not over and this was partly influenced by the admin allowing limited release of OpenAI's GPT-5.6 Sol
@martin_casado @martin_casado on x
Super intelligent. Except not predicting that asking the government to regulate you, will result in the government regulating you.
@deryatr_ Derya Unutmaz on x
Matthew sums it all up! In a great irony, Anthropic CEO Dario Amodei will be etched into history as the man who ruined the great optimism in the age of AI.
@natolambert Nathan Lambert on x
There's a lot of sloppy thinking around open models. You can ban them and make it impossible for US companies to use them, but this won't stop A) global open model progress B) bad actors using them So what exactly is gained by banning open models, including those from China?
@dan_jeffries1 Daniel Jeffries on x
This fight is not over. Not even close. As more Americans (not to mention Europeans and Japanese and Koreans and everyone in the developing world) have frontier AI ripped away from them, it will have massive second order effects that act as a counter veiling force to this
@whiletravelling Evrim Kanbur on x
This is surreal to watch. First, the cult of Anthropic spend years framing AI as an existential threat in every interview. Then watch that narrative spill over and affect the entire industry, not just your own company. Finally, walk into Washington to “help” design the rules to
@jmrphy Justin Murphy on x
If they really start to gatekeep who gets to use the best models, that is a declaration of war. This prospect fills me with the most sincere, bodily cypherpunk will-to-power that I've ever felt (at least since I was a teenager). If they really go down this route, I would go
@cryptopunk7213 @cryptopunk7213 on x
are we really ending the week on a depressing cliffhanger? fable 5 almost certainly won't return soon and when it does it'll likely be US only. gpt-5.6 getting the same treatment - no public access and yet the massive irony of apple lobbying trump to buy chinese memory chips and
@pmarca Marc Andreessen on x
More and more people are saying.
@aianddesign @aianddesign on x
I guess the US government is serving both the AI elite and the AI haters at the same time. When no one gets access to the models we don't need all the massive data centers anymore. #winning
@andrewcurran_ Andrew Curran on x
Semafor is reporting that The US government has lifted its block on Mythos 5 in a letter this afternoon from Commerce Secretary Howard Lutnick to Tom Brown. Fable is not included. This is US only, and covers 100 US institutions, including major companies and government agencies. …
@scottstts Scott on x
I don't think USG wanted to intervene like this, they wanted a booming AI industry and a clear global lead, that's a no brainer But then Dario declares impending doom every chance he got, he sold more fear than tokens, the admin was pressured to react Maybe I'm native, but I
@matthewberman Matthew Berman on x
Limited preview - Dario ruined it for all of us.
@zeeg David Cramer on x
First time I've ever been pro China
@ramez Ramez Naam on x
Staggered AI rollout is not inherently bad. Giving reputable defenders a chance to use powerful models to increase security is good if done predictably, consistently, and transparently. The problem is the capricious, closed door, extralegal way the White House is doing this.
@phl43 Philippe Lemoine on x
Giving government officials the power to decide who gets access to frontier models on a discretionary basis is a recipe for corruption in addition to inefficiency.
@lepadphone @lepadphone on x
Thanks to Anthropic, frontier AI has officially become a national power asset. US AI companies are turning into government puppets. The strongest models go to the state, critical infrastructure insiders, big corporations, and elites. Everyone else gets watered-down, “safe”
NewsMax.com NewsMax.com on x
Report: US Close to Allowing Anthropic to Restore Fable 5 Model
@kimmonismus @kimmonismus on x
Per Axios: Fable 5 is expected to be back and available starting next week. Let's hope it won't be too heavily guardrailed or lobotomized, and that access will be broad. [image]
r/ClaudeAI r on reddit
Scoop: Powerful Anthropic model, Fable 5, on track to return soon
@theobearman Theo Bearman on x
Two things stand out to me here: 1) The title of Annex A (the list of approved entities who can now access Mythos 5 again) is “Anthropic US Entities - Approved”. It appears that no foreign entities, including UKAISI for example, have been granted access to Mythos 5 again as it
@miles_brundage Miles Brundage on x
Lol @ it being addressed to Tom Brown https://x.com/...
@kevinbankston Kevin Bankston on x
This is how you crash the AI market. Frontier model economics won't be sustainable with a small gated customer base for very long, especially as more customers switch to free Chinese open source models.
@andrewcurran_ Andrew Curran on x
The negotiations between Anthropic and the Trump administration are continuing over the weekend. Axios is reporting this morning that they are now very close to a resolution, and the restrictions on Fable could be lifted as soon as the coming week.
@synthwavedd Leo on x
🚨 BREAKING: Anthropic and US Govt insiders expect the administration's limits on Fable 5 could be lifted as soon as this coming week, per Axios. The Pentagon and National Security Agency still have to give Fable 5 the green light, but other government agencies have given the [ima…
@levie Aaron Levie on x
The overton window has shifted on AI regulation. For the past few years there has been a range of debates around how we might regulate AI. There are many different camps on this topic ranging from “0 regulation” to “AI should just be fully stopped and shut down.” And there are
@shashj Shashank Joshi on x
No Mythos access for UK's @AISecurityInst
@sakanaailabs @sakanaailabs on x
Introducing Sakana Fugu: A full multi-agent orchestration system accessible via a single model API. Our ‘Fugu Ultra’ model matches the performance of Fable and Mythos, delivering frontier capability without the risk of export controls. Try it: https://sakana.ai/fugu/ 🐡 [image]
@tonyseruga Tony Seruga on x
Sakana AI revealed a tool that goes toe-to-toe with Mythos and Fable. Fugu is a platform that claims to deliver frontier-grade results by orchestrating multiple models under the hood and routing tasks to the optimal LLM. It runs through a single API endpoint and posts strong
@karankendre Karan on x
Nobody saw this coming Japan is now officially in the AI race and they've released a model that performs on par with Claude Mythos [video]

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