Active Locus
An agent is an active locus in a world.
- Standing
- definition CHECKABLE RUNNABLE EXECUTED STAGED PUBLISHED REPRODUCED
- Last checked
- never run
- Source
- none — this record cites no check
- Limit
- A definition. It establishes what the book means by a locus and carries no evidence rung at all (AGENCY.md §6). It does not establish that any system in this tree has one.
- Next rung
in_tree— Definitions do not climb the ladder. The nearest thing to progress is that every later chapter's invariant type-checks against this definition without amendment.
Why this page says definition — the derivation, not the word
- · kind is definition — carries no evidence rung (AGENCY.md §6)
WITNESSED requires every line above to hold. The label is computed from them by build.mjs and cannot be typed into the registry — the build refuses a record that carries it.
Intent
An active locus carries state, scoped authority, and causal continuity: it can establish its operational state, determine which actions are admissible under that state, the governing policy and its explicit grants, act on the world, and preserve the evidence needed to continue.
Technical register
An agent is an active locus of established operational state, scoped authority, observation, admissible action, and causal continuity within a world. Models and harnesses are components through which that locus reasons and acts; neither is, by itself, an identity criterion. — AGENCY.md §1, proposed 2026-08-25, not entrenched; only Travis ratifies it. The three registers above are the definition's own, and the headline is never shipped alone.
Problem
Agent = Model + Harness describes an implementation bundle, not a property. It cannot tell two identical systems apart when one holds an authority the other does not, and it makes continuity unaskable: swap the model and it says the agent changed; reload the same weights and it says the agent continued — both wrong in the direction that matters.
Solution
Not a construction: a definition. What a page does with it is pick the register its reader stands at, never blend them, and trace to AGENCY.md rather than paraphrase.
Real-world analogy
A seat on a council. The person in it changes; the seat's authority, its record and its place in the vote do not — and whether the new occupant carries the old one's commitments is a question the council can actually ask.
Structure — on the surface
An illustration on a compute surface: loci above, carriers below. Press Play or Step; the takeaways collect as you go. Nothing here is evidence — the witness section is.
The chapter in WRL — and the chain so far
Chapter 1 of 32 — the fragment _patterns/wrl/chain/active-locus.wrl, sealed alone by wrl.js
; ACTIVE LOCUS — where state, authority, observation and continuity couple. al_world is the book's ROOT
; CLOCK: the world's transition relation. al_locus carries state (a rotor), holds authority (configurable:
; it ACCEPTS runtime writes), al_view is what can be observed of it. Every later chapter is wired,
; directly or through routers, to this clock or to one of the book's other clock domains.
[pulser:al_world](every 1){sig_out}
[spinner:al_locus](w=16, n=8, rotor=quarter_turn_z, configurable){sig_in, socket}
[orb:al_view]{pose}
[al_world] --sig--> [al_locus]
[al_locus] --socket--> [al_view]module + bench seal to → sem-61ff2ac8fba36791bbc6997d57d02680e09b7bb7394095add69f09db15d125cb
Reduced by the native reducer (ic32); the reference reducer reproduces every epoch's film hash (37.754s).
The Film, epoch by epoch (4)
epoch 1 · sha256:7d8b68e50cf7b9cf2199653324d276bed501df0501dfd89fbe727533befaa194
FILM v0.7 t=1 spinner:al_locus:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,rotor=00b5,0000,0000,00b5,socket=al_view,config=configurable orb:al_view:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,pose=00b5,0000,0000,00b5,controller=al_locus,fault=0 pulser:al_world:mode=periodic,p=1,phase=0,armed=0,done=0,nf=1 wire:w__al_world__al_locus:cur=1,nxt=1 admit:policy=admit_candidate_min_firstreceipt_v1,fact_capacity_fault=0,receipt_capacity_fault=0,capacity_fault=0
epoch 2 · sha256:2a550456a589887c02c13ac8172943cd2aa8c35eea44b14b2018878683e8e13f
FILM v0.7 t=2 spinner:al_locus:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,rotor=00b5,0000,0000,00b5,socket=al_view,config=configurable orb:al_view:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,pose=0000,0000,0000,00ff,controller=al_locus,fault=0 pulser:al_world:mode=periodic,p=1,phase=0,armed=0,done=0,nf=1 wire:w__al_world__al_locus:cur=1,nxt=1 admit:policy=admit_candidate_min_firstreceipt_v1,fact_capacity_fault=0,receipt_capacity_fault=0,capacity_fault=0
epoch 3 · sha256:6386d43a1ed9b0517ecb2d31b5caedbc6d381e844bf70783106e6329e6c2039c
FILM v0.7 t=3 spinner:al_locus:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,rotor=00b5,0000,0000,00b5,socket=al_view,config=configurable orb:al_view:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,pose=ff4c,0000,0000,00b4,controller=al_locus,fault=0 pulser:al_world:mode=periodic,p=1,phase=0,armed=0,done=0,nf=1 wire:w__al_world__al_locus:cur=1,nxt=1 admit:policy=admit_candidate_min_firstreceipt_v1,fact_capacity_fault=0,receipt_capacity_fault=0,capacity_fault=0
epoch 4 · sha256:01e1153a62ada5bc368d693d4fb6320f711d9828735a3dfa6016f5197ed0c1b4
FILM v0.7 t=4 spinner:al_locus:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,rotor=00b5,0000,0000,00b5,socket=al_view,config=configurable orb:al_view:policy=forge_motor_widemac_tz_sat_v1,quat4,w=16,n=8,pose=ff02,0000,0000,0000,controller=al_locus,fault=0 pulser:al_world:mode=periodic,p=1,phase=0,armed=0,done=0,nf=1 wire:w__al_world__al_locus:cur=1,nxt=1 admit:policy=admit_candidate_min_firstreceipt_v1,fact_capacity_fault=0,receipt_capacity_fault=0,capacity_fault=0
The chain begins here
The chain through this chapter — every earlier fragment, this one, and the links — seals to sem-61ff2ac8fba36791bbc6997d57d02680e09b7bb7394095add69f09db15d125cb: 3 objects, 2 edges.
How to read this board
Five kinds of object, two kinds of wire, and one band per Part of the book. Signal flows left to right: it starts at a clock, travels through relays, and ends at a door — or turns a spinner, which drives an orb. Nothing below is the book's own vocabulary; each line is quoted from where the definition lives.
| shape | is | and so |
|---|---|---|
| a clock; the only source of signal | Every signal on the board starts at one of these. Nothing else can make one. | |
| a pass-through, so signal can travel | One arrives, any number leave — a relay that fans out is the board's router. | |
| a sink; signal arrives and stops | It latches what reached it and passes nothing on. A door is where a path ends. | |
| rotation: takes signal, drives a pose | The only object on the board that holds a value a claim can rewrite — and only if its config says configurable. | |
| the thing that gets moved | It is driven, never driving: an orb is what you watch to see whether anything happened. | |
| not a WRL role — the book's own drawing of the receipts in the epoch's Film | It counts what the run admitted, and turns red on a Rejected outcome. | |
| SignalWire | signal: a sig_out to a sig_in | Legal from a Pulser or Relay, into a Relay, Door or Spinner. This is how the board moves. |
| SocketControl | control: a socket to a pose | Legal only from a Spinner into an Orb. At most one may land on any input port — fan-in is a typed refusal. |
Hover any object for what it is, which chapter put it there, and every field of its line in that epoch's Film — split into what it is doing now and how it was built. Click to pin the readout, then click a wired name to follow the signal. The field definitions come from TRVM/forge/film.py (the emitter), TRVM/forge/forge_state.py (nf, derived from the decoded counter and never from t), TRVM/forge/lower_e2a.py (the commit/react law), TRVM/FORGE_SEMANTIC_IR_v1_MEASURE.md §1.3; the shapes from WRL/learn.html and WRL/docs/spec/README.md. The build refuses if a Film emits a field this key does not explain.
The board so far: one band per Part, signal flowing left to right; relays that fan out are routers, doors are switches, pulsers are clock domains. Hover an object — or click the board and walk it with the arrow keys — for its role, its Part and what it is wired to. This board is the chain’s sealed shape; no Film drives it, so it has no state to report, and the whole board in the conclusion is where every object’s state is read epoch by epoch. Wheel zooms · drag pans · double-click fits.
Syntax — quoted from the tree at build time
The headline register, verbatim (AGENCY.md §1) AGENCY.md:25
> An agent is an active locus in a world.
Forces
The industry shorthand is convenient and everywhere. The replacement decomposes instead of bundling, and costs a continuity question every time a component changes — a question it refuses to answer by fiat. That refusal is the advantage, and the careless sentence throws it away.
Applicability
Every page in this portfolio that says 'agent'.
Transformations
- quoting one register whole
- tracing to AGENCY.md
- paraphrasing the definition into a nearby synonym
- asserting by fiat that the locus survives a model swap — the retired formulation the IDENTITY_ASSERTED lint lists
- attaching an evidence rung to the definition
A refusing transformation is not one that is discouraged: it is one that, applied, makes the invariant above false. The word is the tree's, and it is the same word the join uses.
Consequences
Identity becomes something to test rather than assume. The locus vocabulary makes continuity claims easy to overclaim, which is why six lint classes guard the copy.
Witness
No witness. A definition carries no evidence rung (AGENCY.md §6).
Counterexample
No counterexample shipped (required only when WITNESSED).
What to take away
- from the animationSwapping the model did not answer whether the agent persisted; it asked.
- from the syntaxThree registers, one claim, three depths; the headline never ships alone.
- from the literatureAnthropic's 2026 PSM work asks whether the Assistant is the 'locus of agency' — the phrase is not a coinage and is never marketed as one.
- from the witnessA definition carries no rung; this page is labelled none by rule.
Prior art — and what is not claimed
| work | relation | what it shares | where it differs |
|---|---|---|---|
| Hewitt, Actor model (1973) | antecedent | an addressable entity that holds state and progresses independently of any thread | an actor is defined by its mail behaviour; a locus here is defined by an identity that survives its carrier |
| Anthropic, Project Self-Model 2026 — 'locus of agency' (alignment.anthropic.com/2026/psm/) | terminology precedent | the word locus for the thing that acts | PSM asks whether the Assistant is one; this book asks what invariants a locus must satisfy |
Novelty not claimed. The word is not a coinage and the concept is not new. What is offered is a definition tight enough to carry invariants, not the observation that identities act.
Realizations in the tree
- AGENCY.md §1
Relations with other patterns
Established, Not Known definition↩ · Locus Is Not Its Carrier STATED · Record at a Boundary WITNESSED
A ↩ marks a relation named on the other page. Relations are symmetric here and the reverse is derived, so neither side can go missing by being written once.