# CAST

> A bilateral coordination protocol for commercial payments and financial control.

## Docs

- [Agentic commerce](https://docs.cast.digitalfinancehq.com/foundations/agentic-commerce.md): Agentic commerce needs settlement infrastructure.
- [Deterministic commerce](https://docs.cast.digitalfinancehq.com/foundations/deterministic-commerce.md): Why reconciliation should not exist.
- [The ledger is no longer the system of record](https://docs.cast.digitalfinancehq.com/foundations/ledger-no-longer-system-of-record.md): The event log is.
- [Liability as a service](https://docs.cast.digitalfinancehq.com/foundations/liability-as-a-service.md): Who is responsible when AI acts?
- [The seven structural invariants](https://docs.cast.digitalfinancehq.com/foundations/structural-invariants.md): Seven non-relaxable constraints enforced at the schema level — structural impossibilities, not application rules.
- [The Vendor Event Layer](https://docs.cast.digitalfinancehq.com/foundations/vendor-event-layer.md): A portable proof history the counterparty owns — and the network that compounds from it.
- [Zero-trust operations](https://docs.cast.digitalfinancehq.com/foundations/zero-trust-operations.md): Trust is not a control.
- [Layer 0 — the architecture, enforced](https://docs.cast.digitalfinancehq.com/implementation/layer-0-demo.md): How a working demo proves the principles, with the guarantees shown in the schema itself.
- [CAST Field Guide](https://docs.cast.digitalfinancehq.com/index.md): Both parties sign before the money moves. A bilateral coordination protocol for commercial payments — and the verification layer beneath an agentic economy.
- [Case](https://docs.cast.digitalfinancehq.com/primitives/case.md): A governed exception.
- [Event](https://docs.cast.digitalfinancehq.com/primitives/event.md): An immutable record of something that happened.
- [Lineage](https://docs.cast.digitalfinancehq.com/primitives/lineage.md): The proof is the asset — and it is a property, not an object.
- [The five primitives](https://docs.cast.digitalfinancehq.com/primitives/overview.md): Everything else is a projection of these five objects.
- [Policy Version](https://docs.cast.digitalfinancehq.com/primitives/policy-version.md): A versioned, immutable rule set, pinned to every event.
- [Posting](https://docs.cast.digitalfinancehq.com/primitives/posting.md): A journal-ready ledger entry, created only after mutual authorization.
- [Work Order](https://docs.cast.digitalfinancehq.com/primitives/work-order.md): The container holding the full context and decisions for a payment.
- [Why Confirm & Pay is our first product](https://docs.cast.digitalfinancehq.com/product/why-confirm-and-pay-first.md): Why accounts payable is the first deployable proof of the architecture.
- [Library](https://docs.cast.digitalfinancehq.com/research/library.md): Curated reading on verification, trust, and settlement — the conversation CAST is part of.
- [CAST Perspectives](https://docs.cast.digitalfinancehq.com/research/perspectives.md): Original essays on trust, settlement, and accountability.
- [Reading list](https://docs.cast.digitalfinancehq.com/research/reading-list.md): The research CAST builds on.
- [CAST in 5 minutes](https://docs.cast.digitalfinancehq.com/start-here/cast-in-5-minutes.md): The mental model that makes everything else legible.
- [From systems of record to systems of coordination](https://docs.cast.digitalfinancehq.com/start-here/record-to-coordination.md): The conceptual shift underneath CAST.
- [What CAST is not](https://docs.cast.digitalfinancehq.com/start-here/what-cast-is-not.md): The boundaries we draw on purpose.
- [What is CAST?](https://docs.cast.digitalfinancehq.com/start-here/what-is-cast.md): A bilateral coordination protocol for commercial payments and financial control.