Training worlds for agents

From the Meridians Wiki · Public · Maintained · joint

The same insertion, with a policy in the seat. A kept world an agent is dropped into that it cannot have memorised, a task, a perspective, an interval — and a log that says what it knew, what it did, what it cost, and what changed.

pinned Domain@revision × task × seat × interval × policy@version
  → attributable trajectories
  → a scoped profile: anticipation, discovery, calibration, recovery, cooperation, persistence
  → failures as replayable coordinates, not a scalar

Why a kept world is the right test

History resists memorisation. A world that has run forward holds state no corpus contains; the test is the world's own past.
The same world serves people and agents. Nothing is built twice: the training world a person plays is the one an agent is run through, with the reading swapped for the log.
Families compound. Versioned origins of one world become a fixed instrument a policy can be compared against over time.

Two uses

Testing — one policy, unseen circumstances, how it behaved.
Training — cohorts through parallel origins under varied policies, tools, prompts, or rules; the result is trajectories and comparisons, never a Meridians claim that one is better.

Gates

Claim	Evidence
A run is worth reading.	Someone runs their own agent through a pinned world and changes what they let it do.
The measure is real.	Repeatable across seeds and versions, discriminative between systems, useful to a team improving a model.
The world resists contamination.	A held-out continuation is not predicted better by a system that saw the earlier history, beyond what that history legitimately teaches.
It transfers.	Independent external evaluation; nothing above depends on it.

Boundaries

Systems, not people. Declared synthetic world only — performance is evidence about that world until transfer is shown (WORLD_ENGINE). No omniscient context and no presentation-owned truth for the policy; canonical state stays canonical. The evaluation design lives in CUMULATIVE_VISION §21; the human twin is 12 — The practice record, whose proof programme borrows this leaf's measurement infrastructure — pinned worlds, anchored items, fit — for the independent transfer study. This leaf does not gate the consumer plan.