The three layers
From the Meridians Wiki · Public · Maintained · joint
| Layer | What it is | Where |
|---|---|---|
| System | Which boundary the call crosses: decide (System 1, typed probabilistic answers) or generate (System 2, text). Two of them; orthogonal to the three below. | AI_SYSTEMS, DECISION_MODEL |
| Tier | A capability/cost rung, mapped to one concrete OpenRouter model. Four of them. | TIER_MODEL |
| Category | A modality of LLM work. Every call site belongs to exactly one. Twelve of them. | AI_CATEGORIES |
| Profile | A full category→tier assignment. Switching it re-allocates the whole fleet. | AI_PROFILES |
A call site never names a model. A generation calls modelFor('generate'); the resolver reads the
Director-selected profile (fleet-wide, from record/aux/meta.json), looks up the tier that
profile assigns to generate, and returns that tier's model. Change the profile → every call of
that modality re-routes. A decision calls decisionModelFor('action'), which returns the one
DECISION_MODEL; the category is stated for attribution and the call ledger, and leaves room for a
per-category decision allocation later without touching call sites.