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Concepts — L2 model

The modeling vocabulary an integrator uses to declare an institution's shape. The L2 YAML is the single source of truth for every shipped dashboard — feeding a different YAML changes the dashboards' contents without touching code.

Each page below explains one primitive in isolation, then shows a concrete example pulled from the active L2 instance (or spec_example as a fallback if the active L2 has no entity of that type yet).

Primitives

  • Account — the singleton, 1-of-1 GL or external counterparty.
  • Account template — the SHAPE of an N-of-many account class (per-customer DDA, per-merchant settlement) materialized at posting time.
  • Rail — a single money-movement primitive (TwoLeg posts debit + credit, SingleLeg posts one leg reconciled by a template or aggregating rail).
  • Transfer template — multi-rail bundle with an expected_net close-out (e.g. "ACH origination cycle").
  • Chain — required or optional parent → child firing rule; XOR groups encode "exactly one of these MUST fire".
  • Limit schedule — daily outbound-flow cap per (parent_role, transfer_type).

For the broader institution-tour view that walks every entity at once, see Training Story. For the data- side feed contract those entities project into, see Schema v6.