Chastikey update: Inferno (the Premium brain) now has a fair-use limit. You never get blocked — you get moved to Blaze for the rest of the day.

Hey everyone — Vitalys here, the solo dev behind Chastikey (the AI keyholder app).

I changed something this week that affects the heaviest Premium users, and I'd rather explain it myself than have you discover it mid-scene.

Short version: Inferno — the flagship brain — now has a fair-use ceiling: 60 messages a day, 250 a week, 800 a month. Past any one of those, the conversation keeps going on Blaze until that window resets. You are never blocked, never shown an error, never asked to pay to continue. Blaze and Spark have no ceiling of their own, and nothing about your monthly 5,000-message pool changed.

Why I did it

Inferno doesn't run on the same engine as Spark and Blaze — that's been true since the beginning of September and I posted about it then. What I underestimated is how much more it costs. Per message it's roughly four times the entry engine, and the reason is more interesting than "bigger model":

Every turn in a long conversation re-sends the whole transcript. Engines cache that and re-read it cheaply on the next turn — except the one behind Inferno re-reads a small fraction of what the entry engine does, so it pays close to full price for your entire history, every single message. The longer and better your conversation gets, the more each reply costs me. That is exactly backwards from how I want to be incentivised.

I looked at what people actually do before picking a number, and the shape surprised me. The median Inferno day is 18 messages. Three quarters of days are under 51. But the heaviest evenings run to 257 messages in a single sitting, and a monthly bucket cannot see that — someone can empty a month's worth of the expensive brain in two nights and then spend twenty-eight days on the cheap one, which is the worst possible version for both of us.

So: a daily rail for the binge, a weekly rail for the multi-day binge, and the monthly one as the backstop.

Who this actually touches

If I replay it over August: of the 99 people who used Inferno at all that month, 37 would have crossed one of the three ceilings at least once — meaning one evening where the last stretch of the conversation ran on Blaze. The other 62 would never have noticed. If your usage looks like the median, you will not meet this limit.

What happens when you do hit it

Nothing dramatic, and this is the part I care most about getting right. The message sends. You get a reply. It comes from Blaze instead of Inferno, and tomorrow you're back on Inferno.

I want to be blunt about why that matters to me: I had the other kind of limit once. Back in July there were hidden per-day and per-hour rails that blocked you outright — one Plus subscriber sat at 24% of their monthly quota and was locked out for fifteen hours, and the app told them they'd hit their monthly limit, which was a lie. I deleted those rails the same week and I'm not bringing them back. There is now a test in the codebase whose only job is to fail if anyone ever turns one of these new ceilings into a refusal.

The message packs now sell Inferno

The top-up packs used to sell ordinary messages. That stopped meaning anything when I made them Premium-only: Premium already includes 5,000 messages a month and essentially nobody empties that pool, so the shelf held something you couldn't run out of.

So they now buy Inferno messages — the thing you can actually run out of. One credit = one Inferno message past the ceiling. The sizes are the windows, which is what makes them readable:

• 60 — one more full day at the cap
• 200 — most of a week
• 600 — most of a month

Credits are a lifetime balance: they don't expire and they don't reset with the month. If you already bought credits, you didn't lose anything — your balance now buys the scarce brain instead of the abundant one, which is strictly a better deal than what you paid for. Nothing to claim, it's already true.

Packs are bought in the app (App Store). Your included monthly messages are always spent first; credits only ever come out when a ceiling is actually in the way.

What you'll see

Open the brain picker and the line under Inferno now names all three rails instead of a single number:

today 48/60 · this week 190/250 · this month 711/800

The one that will stop you first is highlighted. Before this week that line showed one number labelled "this month", which on most days was quietly reporting the wrong rail — my fault, and fixed.

Two honest caveats:

• This display is live on chastikey.eu right now. In the iOS app it arrives with the next release, so until then you can meet a ceiling before you can see it.
• The day and week counters started at zero the morning this shipped. Nobody was charged for messages they'd already sent.

What did NOT change

• No subscription price moved. Plus and Premium cost exactly what they cost yesterday.
• The monthly pool is untouched: 5,000 for Premium, 1,000 for Plus, 50 for Free.
• Blaze and Spark have no ceiling. Free and Plus users are not affected by any of this.
• No hidden rails. Three numbers, all three visible in the app, all three named. If I ever add a fourth, you'll read about it here first.

The part where I admit the obvious

Yes, this is me taking something back from the people who use the app the most, and yes, I'm selling the thing I just made scarce. I don't have a way to say that which sounds good. What I can tell you is the alternative I rejected: quietly moving Inferno onto a cheaper engine and saying nothing, which is the standard move and which you'd have felt within two days without ever knowing why.

I'd rather cap it in the open, show you the numbers I used, and let you decide whether the pack is worth it.

Questions welcome — I read everything here.

— Vitalys