GM Brain/ holds five kinds of file. Three of them are a depth ladder, one is a state machine, and one is the write path. Knowing which is which is most of knowing where a new rule belongs.
The depth ladder
The three are distinguished by exactly one property: whether the GM can open them during a turn.
The pinned Ladder. @Missing file loads on every turn, automatically, whole. Measured with characters Γ· 4 it currently runs a little under seven thousand tokens, every time the GM thinks β measure it yourself rather than trusting this sentence, because it moves whenever somebody edits it.
It shares pinning with four files in total, and the other three are data: @Missing file, @Missing file, and @Missing file. One pinned instruction file, three pinned state files. That ratio is deliberate and the visibility chapter defends it.
The Ladder holds the turn procedure and almost nothing else: time and life first, then input, refusal, the cascade, checkpoint, voice, write, scrub, persist. Everything it needs elsewhere it names by title.
Do not add reference material to it. If a rule feels important enough to pin, it is almost always cheaper to have the Ladder name the file holding it β naming costs about ten tokens once, pinning costs the file's full length forever.
The cards. GM Brain/Cards/ β most sit between five hundred and roughly twenty-five hundred tokens, with the median comfortably under a thousand. A card is the operative layer: thresholds, a short procedure, the exact schema fields to write. One opens when the Ladder names it, and it is gone again afterwards.
A card is not an essay about a subject. It is what to do about that subject, in the order you do it.
The mechanics. GM Brain/Mechanics/ β three thousand to nearly thirty thousand tokens each. This is the world-book, the deep reference a card is a summary of.
Never read whole during play. That is not a style note. The largest mechanic in this project measures 5.1Γ the pinned Ladder β one file, four times the cost of the thing that loads on every single turn. Cards exist precisely so the mechanics never have to be opened at the table.
The state machine
GM Brain/Phases/ is the layer both books used to skip, and it is why the same turn procedure produces a conversation and a chase.
Eleven of them are phaseMode values on Scene State β Downtime, Adventure, Conversation, Travel, Combat, Investigation, OOC, Multi-scene, Somewhere Else, Absence, Player Control Loss. That enum is the state; the phase file is what the state does. @Missing file sets minute costs, beat floors and what people are actually doing while they talk. Phase files run about the size of a large card.
Four more are tints, not states. Multi-Unit, Storyteller, Off-Screen and Maturity Link modify whatever phase is running rather than replacing it. They are switched on by installation flags, not by the turn. A tint has no phaseMode value and never will β writing one into that enum is a rejected push.
Adding a phase means adding an enum value and the file, or the mode is unreachable. Adding a tint means neither.
The write path
GM Brain/Tools/ β roughly one per file type the GM writes. These are the shortest files in the project, a hundred-odd tokens each, and they are the least understood.
A Tool is a registered post-condition validator. It fires after a write, not before it. A read trigger lands during preprocessing; an update trigger lands during postprocessing, after the change it is riding on has already happened.
That timing is the whole design constraint: a Tool cannot instruct the write it fires on. It arrives too late. It can check what landed, correct it, cascade to a second file, or refuse to let a stale record sit β it cannot shape the value. Anything that must shape a write belongs in a card the Ladder names, or in a narrative trigger on post_player_message, which arrives before anything has been decided. @Missing file is the authority on that ordering.
A Tool written as a paragraph of advice is a Tool that does nothing. Write the check.
The rule that holds it together
The pinned file names. The card carries. The mechanic explains. The phase decides which card. The tool checks what landed.
Every time something feels important enough to promote a layer, check whether naming it from one layer up would do. It usually does.
