Wave 1 · record #1sys.descriptor.defined

#1 · the first fragment's doer

When the engine takes it, the machine stores the doer and notes whom it waits for. It has no place for a Cell's return — which is why one is written later (#25–#27).

Came froma personThe fragment's author added it at the door, right after the listener — the second half of the template. step 3

Read as

when it came in at the door

3Record #1 enters the logLOG · append
a wave is settlingengine: next: #0membrane: waiting at #0
The log
#0a listenerenginemembrane
#1a doernew
end of the log
The log
What before after
records in the log 1 2
#1 — a doer · sys.descriptor.defined
The door adds the second record as #1: the first fragment's doer, note.echo, unchanged. The machine has not reacted to either yet.
Where it happens appendEmissions()Vol. 02 §4.1 · Vol. 03 §1
The only function that adds records to the log. Each new record gets the next free number, at the end.
Specification
Vol. 02 §4.1 · Vol. 03 §1
Code
appendEmissions() in core/registers/append-emissions.ts, line 14: the new record gets the next free number
Journal
LOG · append · offset: 1, kind: sys.descriptor.defined · by engine
Picture
records in the log: 1 → 2
core/registers/append-emissions.ts · build 043cc8b
// The one LOG writer (Vol. 02 §4.1, Vol. 03 §1): emissions become tuples by
// receiving the next dense absolute offset — `base + window.length` — and
// nothing else ever grows the log. Each append is journalled under the
// ambient context, so a batch born of a propagated tuple carries that
// tuple's offset as its cause — the cube's provenance line (ADR-002).

import type { WaveEmission, WaveTuple } from "../wave/gate";
import type { RegisterFile } from "./register-file";
import { recordTransition } from "./record-transition";

export function appendEmissions(file: RegisterFile, emissions: readonly WaveEmission[]): void {
const engine = file.registers.engine;
for (const emission of emissions) {
const tuple: WaveTuple = { ...emission, offset: engine.base + engine.window.length };↑ the new record gets the next free number
engine.window.push(tuple);↑ it is added at the end of the log
recordTransition(file, "engine", "LOG", "append", {↑ the change is written into the journal
offset: tuple.offset,
kind: tuple.kind
});
}
}
AGPL-3.0-onlyThe Lab's demonstration environment, as this fragment ran it (build 043cc8b). The code may change, and may differ from the code of a working machine.
Nest VM core, incubated in the CoAgnes garden · build 043cc8b (2026-09-21) · this file last changed in f36e70d (2026-08-18)

What	before		after
records in the log	1	→	2
#1	—	→	a doer · `sys.descriptor.defined`

when the engine took #1

7The engine takes #1ENGINE.CURSOR · propagate
a wave is settlingengine: working on #1membrane: waiting at #0
The log
#0a listenermembrane
#1a doerengine · working
end of the log
The engine
What before after
pointer — the next record to take #1 #2
The engine moves on to #1, and the machine reacts to it.
Where it happens takeNextTuple()Vol. 02 §4.1
The engine's step: take the record under its pointer and move the pointer on — or stop, if the pointer has reached the end.
Specification
Vol. 02 §4.1
Code
takeNextTuple() in core/registers/take-next-tuple.ts, line 15: at the end of the log, the engine stops
Journal
#1 · ENGINE.CURSOR · propagate · offset: 1 · by engine
Picture
pointer — the next record to take: #1 → #2
core/registers/take-next-tuple.ts · build 043cc8b
// ENGINE.CURSOR advance (Vol. 02 §4.1) — the machine's instruction pointer:
// returns the tuple at the cursor and moves it forward exactly once, or null
// at quiescence. Advancing IS the context switch: the ambient wave context
// moves to the propagated tuple in the same movement, so every transition
// journalled during its propagation is attributed to it — the cube's spine.
// The cursor never rewinds.

import type { WaveTuple } from "../wave/gate";
import type { RegisterFile } from "./register-file";
import { recordTransition } from "./record-transition";
import { setDriver, setWaveContext } from "./set-wave-context";

export function takeNextTuple(file: RegisterFile): WaveTuple | null {
const engine = file.registers.engine;
if (engine.cursor >= engine.base + engine.window.length) return null;↑ at the end of the log, the engine stops
const tuple = engine.window[engine.cursor - engine.base];
engine.cursor += 1;↑ the engine's pointer moves on by one
setWaveContext(file, { offset: tuple.offset, phase: "propagate" });
setDriver(file, "engine");
recordTransition(file, "engine", "ENGINE.CURSOR", "propagate", { offset: tuple.offset });↑ the change is written into the journal
return tuple;
}
AGPL-3.0-onlyThe Lab's demonstration environment, as this fragment ran it (build 043cc8b). The code may change, and may differ from the code of a working machine.
Nest VM core, incubated in the CoAgnes garden · build 043cc8b (2026-09-21) · this file last changed in 6730f58 (2026-09-13)
8The doer is added to the figureBIND.DEFS · register-descriptor
a wave is settlingengine: working on #1membrane: waiting at #0
The log
#0a listenermembrane
#1a doerengine · working
end of the log
The figure
What before after
doer note.echo — acts on note.gate; releases note.echoed (release@1)
when note.gate is ready, it wakes — note.echo
The machine writes the doer's description into its list of doers, and notes that note.echo waits for note.gate. It was born knowing nothing of Cells: it has no place for a Cell's return.
Where it happens registerDescriptorDefinition()Vol. 02 §4.2
Stores a doer's description under its name, and lists it under every listener it waits for.
Specification
Vol. 02 §4.2
Code
registerDescriptorDefinition() in core/registers/register-descriptor-definition.ts, line 19: the description is stored under its name
Journal
#1 · BIND.DEFS · register-descriptor · id: note.echo, interests: ["note.gate"] · by region:root
Picture
doer note.echo: — → acts on note.gate; releases note.echoed (release@1)
core/registers/register-descriptor-definition.ts · build 043cc8b
// BIND.DEFS and DISPATCH write (Vol. 02 §4.2): the registration payload
// lands as data; the dispatch table indexes the descriptor id under every
// declared interest (the activation knot plus every demand for an operator
// bind, the one subscription for an emit descriptor). Duplicate-id rejection
// is the station's verdict (ADR-011 finding 3) — this op only records an
// accepted registration.

import type { DescriptorDefinedPayload } from "../topology/gate";
import type { TopologyRegisters } from "./topology-registers";
import type { RegisterFile } from "./register-file";
import { recordTransition } from "./record-transition";

export function registerDescriptorDefinition(
file: RegisterFile,
region: TopologyRegisters,
payload: DescriptorDefinedPayload,
interests: readonly string[]
): void {
region.bindDefs.set(payload.id, payload);↑ the description is stored under its name
for (const interest of interests) {
const list = region.dispatch.get(interest);
if (list) list.push(payload.id);
else region.dispatch.set(interest, [payload.id]);↑ listed under the listener it waits for
}
recordTransition(file, `topology:${region.regionId}`, "BIND.DEFS", "register-descriptor", {↑ the change is written into the journal
id: payload.id,
interests
});
}
AGPL-3.0-onlyThe Lab's demonstration environment, as this fragment ran it (build 043cc8b). The code may change, and may differ from the code of a working machine.
Nest VM core, incubated in the CoAgnes garden · build 043cc8b (2026-09-21) · this file last changed in f36e70d (2026-08-18)

What	before		after
pointer — the next record to take	#1	→	#2

What	before		after
doer `note.echo`	—	→	acts on `note.gate`; releases `note.echoed` (release@1)
when `note.gate` is ready, it wakes	—	→	`note.echo`

when the membrane passed #1

10The membrane passes #1MEMBRANE.CURSOR · sweep
a wave is settlingengine: at the endmembrane: passing #1
The log
#0a listener
#1a doermembrane · passing
end of the logengine
The membrane
What before after
pointer — the next record to pass #1 #2
The same for #1: a description asks nothing of the world. Both pointers have reached the end of the log.
Where it happens sweepNextTuple()Vol. 02 §4.6 · Vol. 07 §3
The membrane's step: pass over the record under its pointer and move the pointer on — exactly once per record.
Specification
Vol. 02 §4.6 · Vol. 07 §3
Code
sweepNextTuple() in core/registers/sweep-next-tuple.ts, line 16: the membrane's pointer moves on by one
Journal
#1 · MEMBRANE.CURSOR · sweep · offset: 1 · by membrane
Picture
pointer — the next record to pass: #1 → #2
core/registers/sweep-next-tuple.ts · build 043cc8b
// MEMBRANE.CURSOR advance (Vol. 02 §4.6, Vol. 07 §3): the membrane's own
// reading of the one log — the second reception of one publication, never a
// second truth. The cursor advances exactly once per offset per machine:
// the exactly-once discharge guarantee lives in this movement.

import type { WaveTuple } from "../wave/gate";
import type { RegisterFile } from "./register-file";
import { recordTransition } from "./record-transition";
import { setDriver, setWaveContext } from "./set-wave-context";

export function sweepNextTuple(file: RegisterFile): WaveTuple | null {
const engine = file.registers.engine;
const membrane = file.registers.membrane;
if (membrane.cursor >= engine.base + engine.window.length) return null;
const tuple = engine.window[membrane.cursor - engine.base];
membrane.cursor += 1;↑ the membrane's pointer moves on by one
setWaveContext(file, { offset: tuple.offset, phase: "sweep" });
setDriver(file, "membrane");
recordTransition(file, "membrane", "MEMBRANE.CURSOR", "sweep", { offset: tuple.offset });↑ the change is written into the journal
return tuple;
}
AGPL-3.0-onlyThe Lab's demonstration environment, as this fragment ran it (build 043cc8b). The code may change, and may differ from the code of a working machine.
Nest VM core, incubated in the CoAgnes garden · build 043cc8b (2026-09-21) · this file last changed in 6730f58 (2026-09-13)

What	before		after
pointer — the next record to pass	#1	→	#2

Choose a step in the stack — or press →.

A doer's definition

Brings a doer into the machine: its name, the listener it acts on, what else it needs, and what it does once it may act — release a fact itself, ask the world for a fact, or ask the world for a whole Cell. The return doer is the simplest sort: it writes one fact when its listener is ready.

#1sys.descriptor.defined a person

envelope
`offset`	`1`Its place in the log — the only address a record has. The engine gives it when the record is added, the next free number, and it never changes.
`kind`	`sys.descriptor.defined`Which of the four kinds of record the machine knows. The kind decides what the payload holds.
`key`	∅No lane (∅): a definition belongs to the whole machine, not to one lane.
payload
`id`	`note.echo`The doer's name, unique in the machine.
`meta`	title · glossWords for people — a title and a gloss. The machine's own parts never read them.
payload.operator
`on`	`note.gate`The listener it acts on: when that listener is ready, the doer's lane becomes active.
payload.operator.service
`instruction`	«Release the note as it was heard.»What it does, or asks the world to do, in words.
`action`	`release@1`A local action chosen by name: the machine performs it itself, and nothing crosses the membrane.
payload.operator.service.emit
`writes`	`note.echoed`The type its result is written as.

end · #1

In the specificationVol. 03 §1Vol. 03 §2Vol. 03 §5Vol. 04 §2.2Vol. 06 §2Vol. 06 §3Vol. 12 §3

Names it shares with other records

note.echo — also on #43 the release

The record as the machine keeps it

{
 "offset": 1,
 "kind": "sys.descriptor.defined",
 "key": null,
 "payload": {
  "id": "note.echo",
  "meta": {
   "title": "The note, released",
   "gloss": "One bind: when the knot is ready it releases what it heard — a local action, nothing crosses to the world."
  },
  "operator": {
   "on": "note.gate",
   "service": {
    "instruction": "Release the note as it was heard.",
    "action": "release@1",
    "emit": {
     "writes": "note.echoed"
    }
   }
  }
 }
}