The practice record — the journey, the measure, the proof

Status: the plan. Meridians grows people through repeated, generated, emotionally consequential hours in worlds made for them, measures the change on a calibrated scale, and proves it transfers. It never passes a verdict on anyone. Every claim below carries its evidence status: designed / measured in fiction / shown to transfer.

What we monopolise (2026-09-18)

The causal simulator, enabled by Meridians World Search (MWS). Not a library of visual novels and not a persistent universe yet: a consequential situation turned into a kept world whose pathways MCTS has grown and priced, rehearsed through the VN, remembered, and retried. That is the value, and value today lies in causally deploying simulations from a voice interview — the person tells us what they are preparing for; the world is built; the pathways are searched; they rehearse before reality does it for them (01). Micro sonic analysis is the value-add on the felt grain of those hours. The primary roadmap is Causal MCTS VNs; the VNMMO is a stretch goal on a separate roadmap: a persistent universe that relies on the same simulator, more automated, kept on the side until the simulator has earned it (specs map). The record below is what the simulator leaves behind in the person, and it is the part no one else can regenerate. The full argument — the compound asset, why the simulator is a sci-fi technology in earnest, the weak points, and the build-ordered roadmap — is 14.

The durable thing a training world leaves behind is not the world. It is the person's record of having been in it: what they committed to under what they knew, what they expected and what happened, which seats they re-entered, what they carried across runs — and, across a journey, how far they moved.

The journey — a concierge live service

The hour (training worlds) is one session in a journey:

journey = trait × person × [hour₁ … hourₙ] × weekly cadence × debrief
hourₖ   = world_k(question_k, forks aimed at θ̂_{k−1}) → reading_k → θ̂_k
anchor  = a frozen hour, unchanged for everyone, at baseline · mid · end — what pins the scale

Six to ten hours over as many weeks, aimed at one trait the person named (courage under loss, romantic judgment, perspective-taking, calibration, promise-keeping). Week one baselines; the middle weeks grow, each new world generated from the last reading — new setting and cast, same trait, forks pitched at the edge of what the person can see; a transfer world near the end that resembles nothing before it; a delayed retention return; then the journey's reading, in the world's words, with its uncertainty. The next hour is prepared between sessions by the Factory pipeline from the record; a concierge voice frames each hour, receives the reading, and proposes the next. Spacing and the debrief are what make repeated hours compound rather than blur. Sold as a monthly subscription on trait change and emotional experience; the operator subscription (04) stays as the floor for people who use the substrate.

The measure — Rasch

ln[ P(right move at fork i) / (1 − P) ] = θₙ − δᵢ

A fork in the flag plan is an item; the decision on the canonical good route is the keyed response; δᵢ is how hard the right move is to see (Fate's belief gives the prior, players give the estimate); θₙ is the trait as this person expresses it, in logits. Information P(1−P) peaks at θ = δ, so the fork that measures best is the one that teaches best; SE(θ̂) ≈ 1/√ΣI is the honest uncertainty on every reading; fit finds bad forks, keys that are really values disagreements, and worlds that measure two things. Rasch rather than a tally or a portrait because of specific objectivity: players take different routes and meet different forks, and only a calibrated, anchored scale puts them on one θ regardless.

Three constraints make that scale real rather than nominal (training worlds §5a):

• Pinned by frozen anchor hours. Generated hours are new items every week, and a bottleneck re-staged in a new setting is a new item whose difficulty drifts; with only the person linking two hours, "they grew" and "the world got easier" are the same data. The scale is pinned by a small library of worlds that never change, played by everyone at baseline, mid-journey, and end, plus counterbalanced ordering of generated hours across the cohort so drift averages out.
• Hours are testlets. Forks on one route depend on each other, so an hour's information is deflated for within-hour dependence (≈ ±1.3 logits per hour, not ±1).
• Per person an interval, per cohort a claim. Δθ = θ̂_end − θ̂_start carries SE(Δθ) ≈ 0.6–0.7 after a full journey — wider than the change a journey can plausibly produce — so the person's reading shows the interval and the movement inside it, never a growth pass/fail. "Changed" is asserted for a cohort, when |Δθ| > 2·SE(Δθ) on anchored items and holds on the transfer world and at retention; otherwise "no clear change yet".

Partial credit and many-facet extensions (world, seat, occasion, generating model) when needed. The unit already fits: Fate runs in logits.

What the record is

commitment at a stated vantage → consequence → reading back → next insertion, harder or from another seat

• Yours. Attributed to one person against one kept world. Another studio can make a better world; it cannot make your history in this one.
• In fiction, about the play. Anticipations met, stances held under cost, perspectives taken, promises kept — described in the world's own words, from a declared seat, over a declared interval.
• Read back, never shown live. The ending card and the replay compare are where it lives. A gauge during play turns training into optimisation and breaks immersion.
• Steers the next hour. Every VN decision is useful information about the person; the record's first consumer is generation, which pitches the next world at the edge of what they can see and presses where they surprised the instrument (latent-traits spec).

How what we sell feeds it

• The training world starts it cheaply: one hour, one world, one reading.
• The pocket dimension deepens it: what another seat knew is the sharpest thing a debrief can say, and only other wills can supply it. Entry is earned in training worlds; the reading stays the person's own inside the crowd (01).
• Agents get both as twins: the same kept world, the same log, a policy in the seat (13).

What it is not

• Not a score, rank, diagnosis, or prediction of a person. The reading is a mirror the player holds up to their own run (promise).
• Not clinical. Trait labels are the world's — held the line at the hearing — not inventory scales; the latent-model boundary applies to the player as to a character.
• Not sold to anyone else. Nothing about a person leaves the person.

The proof programme

We claim trait change, so we owe the evidence, rung by rung, each named on the tin:

Copy never runs ahead of the rung: built to change how you decide → measured to change how you decide in these worlds → shown to change how you decide. The old gate was a reason for silence; this is a programme with dates. Ethics, minimal: informed consent that the service is designed to change behaviour; the person owns and can delete their record; traits are opt-in and named by the person; no protected-characteristic inference; no third-party disclosure; a referral path if a journey surfaces distress.

Still true: the simulation cannot certify its own transfer (WORLD_ENGINE). Rung three is how we certify it, externally.

See 05 — The moat for the world-side twin, human practice for the loop that produces the record, and the training worlds spec for the unit that starts it.

Source: 2026-09-10 concierge live service / Rasch handover 🔒.