I’m a dermatologist. I’m supposed to say there is no amount of safe sun exposure. But I won’t, because that’s a lie. The attached shows how much sun is safe in different cities at different times of year. What do I mean by ‘safe’? I mean this: UV causes DNA damage and skin cancer. But, shockingly, your body repairs that damage. As long as the damage doesn’t outpace repair and start accumulating it shouldn't increase your risk of skin cancer. Data just came out that tells us how much UV you can get without damage accumulating. They took the people most susceptible to DNA damage from UV and exposed them to UV, then did skin biopsies to measure the damage, then more skin biopsies to measure the repair, and repeated it daily for 4 days. At 1.6 ‘Standard Erythemal Dose’ (SED) there was no accumulation of damage. So, the attached charts show how much sun it takes to get 1 SED in different cities at different times of the year at different times of day. And there are extra safety margins built in. It assumes a perfectly clear day with zero air pollution and that the sun is hitting your skin perpendicularly. Unless you’re laying flat, most sun is hitting you at an angle, which isn’t nearly as intense. But a bigger question you might be asking is ‘Why would a dermatologist be telling you to get sun in the first place?’ Because getting sun reduces your risk of death. Mostly by reducing your risk of heart attacks and strokes. That is very well proven. But it’s also very likely that sun exposure reduces your risk of autoimmune disease, dementia, cancer and depression. It’s just not as well proven as the protection against heart attacks and strokes. And before you reply and say ‘just take vitamin D!’, know that it has been ROBUSTLY proven that vitamin D has little (if any) benefit for preventing any of the above. Vitamin D is mostly useful as a marker of if you’re getting enough sun. What do I do myself and what do I tell my patients? Get as much unprotected sun exposure as you can without getting a burn. That’s my GUESS as to what has the best risk/benefit ratio. Dying of skin cancer is actually really rare, especially when compared to the risk of heart attacks, strokes, autoimmune disease, dementia and other cancers. But I’ll admit it’s not for sure best to get as much sun as possible, since sun does increase the risk of skin cancer and it might be the case the benefits plateau at a low level. So, if you’re really worried about skin cancer stick to the charts. The best science I can find says that amount won’t cause skin cancer. The takeaway? Sun is good for you, just don’t get a burn.

i had my first billing error user from vietnam 🇻🇳 this is how you can prevent it: • billing grace periods • set it to the max: 28 days this will help renewals go through works best if you have no overheads not perfect, but increase your chances

> Last year, I was constrained by tokens. I fixed that by joining OpenAI > Then I was constrained by CPU, now I feel my constraint is actually *attention* .@steipete came to agents/pizza/wine to demo his agentic engineering workflow

Obvious in retrospect, but I didn't really anticipate: Fable: Performing Final Review of <Awesome Feature> Also Fable: I appear to have introduced a critical security vulnerability. <This model's safeguards flagged this message.> Opus 4.8: Doesn't look like anything to me.

Super fascinating: Some freaks on Reddit got Claude Fable 5 to leak the internal CoT reasoning chains (not the prettified output you normally see). And it looks very bizarre, almost like an alien language. Some of it reminds of logical notations. It's much less like normal language than previously assumed. This is because this form is highly token-efficient (compressed). The internal reasoning chains are a closely guarded secret of every AI lab.

I've noticed recently that the Gemini 2.5 Flash-Lite model is producing a lot of 503 errors. Around 30% of my daily requests are failing. The reason is simple: model overloaded. Gemini 2.5 Flash is more expensive, so I'm not sure I'm ready to switch yet, but I don't really see any other option for now. Curious how everyone else is dealing with this.

Wanted to do a quick follow-up on the tool I mentioned in the quoted post. I built it for my own apps and the results genuinely surprised me. Users actually want to share their opinion. They upvote, they request features, they care about the product they use. Here are real screenshots from one of my apps. These are requests people left, voted on, and that I actually shipped. What surprised me most: users want to be heard. Just give them a way to speak and they will. I’m really happy to share this tool with you soon. Almost there just finishing the last bits this week. Bookmark this. Next week I’ll be announcing my first build-in-public SaaS 👇

Russia is my 2nd best "customer" (downloads), but they can't pay (Rico FTW). My plan was to keep them for download ASO, but first 1-⭐ ratings coming in. Was not aware that the change was so recent, I guess my russian brothers are angry, привет. I guess it's better to ditch it?

I just found out that Russia hasn’t been able to make App Store payments since April. I don’t think I get many downloads from there, but I’m thinking of removing it to avoid any trouble