The five primitives

CAST is built on five canonical objects. Everything an operator, an auditor, or an agent sees is a projection of these five. They do not change between verticals — only the event types, policy rules, and work-order structures do.

Event

An immutable record of something that happened. The only source of truth.

Policy Version

A versioned, immutable rule set, pinned to every event at processing time.

Work Order

The container holding the full context and decisions for a payment.

Posting

A journal-ready ledger entry, created only after mutual authorization.

Case

A governed exception — dispute, non-response, breach, or gap.

And one property: lineage

Lineage is not a sixth object. It is the immutable hash chain that binds every posting back through the events, decisions, and policy version that produced it. It is rendered throughout CAST as lineage() — a function over the five objects, not a thing beside them.

Lineage — the proof is the asset

How the hash chain makes a transaction insurable, financeable, and survivable.

The model at a glance

Event ──▶ Policy Version ──▶ Work Order ──▶ Posting
                                  │
                                  └──▶ Case (on exception)

lineage() binds every step back to the originating Event.

Append-only by design. Mutual authorization is enforced before any high-risk posting. This produces verifiable proof without added complexity.

From systems of record to systems of coordination Event

Event

Policy Version

Work Order

Posting

Case

​And one property: lineage

Lineage — the proof is the asset

​The model at a glance

And one property: lineage

The model at a glance