Roads and bridges
Cog walks the finished road end to end before telling you it is done — every step, the whole way.
One unbroken road. Nothing missing, nothing you cannot walk up.
The best bit
What you asked for is what you got.
When Cog finishes something they do not walk away. Cog goes back over it, counts it, measures it, and reads you the numbers they found. So you never discover on Saturday that the bridge you crossed on Tuesday had a gap in the middle of it.
Take the front off. Saying a house is walk-in is easy — Cog went in and stood in the middle of it.
What checking means
Cog reads the world back, block by block
A build can look perfect from one angle and still be wrong. So Cog reads the actual blocks back out of the world — and everything standing on them — and checks the things a picture cannot show you: whether the road is one unbroken shape, whether every gondola sits the same distance from the hub, whether the lamps really go dark when the power does. Cog runs the same checks over the plan before the first block lands, so most trouble never gets built in the first place.
What gets checked
What Cog goes back over before saying it is done
The ferris wheel
Every seat gets measured out from the hub, rather than trusted to the drawing. A wheel with one gondola sitting proud of the others is not a wheel.
Every seat true. It turns without catching.
Anything Cog designed
A design names the block for every place in it before a single one goes down, so Cog can check the whole thing rather than spot-check it.
Every block where the drawing said it would be.
Whether you can really go inside
You cannot work this out on paper — we tried. So Cog stops calculating, stands outside, picks the spot deepest inside the building, and walks to it on foot with the same physics you have. Either they are standing in there at the end or they are not.
Cog goes in and stands there. On foot, like you would.
A game Cog wrote
Rules with one character wrong load perfectly, report success, and then do nothing at all, forever, without a word. So every rule gets set off on purpose first: a snowball dropped in the goal mouth, a score driven to its winning value, the clock wound to the tick a timer waits for.
Every rule fired once before you play it.
The hidden door
Cog pulls the lever and watches the wall slide across, then pushes it back and watches the doorway return. Then again, at every width, because a secret door that works once is a hole.
Opens and seals every time, at any width.
Redstone
The lever works the first time
Redstone is where clever machines fall over — one block out of place and the whole circuit is dead. It is hard enough that when somebody sat the best AI models going down in front of it, they got it right about a quarter of the time. So Cog does not improvise the wiring. Cog places circuits from a library that has already been built and checked, which is why the hidden door slides open the first time you flip the lever, and the hundredth. Read the six wire rules that library is built on.
And if it is not right
Cog tells you before you find out yourself
The point of checking is not a clean score. It is that when something is wrong, you hear it straight away, from Cog, instead of finding it on Saturday halfway across a bridge.
So Cog says what they built, what they went back over, and anything they could not finish. No quiet failures, no "done" on something that is not.
Read next
Where to go next
- How it works — what happens between asking and finished.
- What you can ask for — everything Cog will go and do.
- The six redstone wire rules — why the lever works first go.
Be in the first worlds.
We are opening a small number to begin with. Put your name down and we will tell you when yours is ready.