# Protocol Contract

> The agreed rules of a protocol, such as its messages, formats and sequences, that both ends must honor.

Record: `lexicon:protocol-contract`
Kind: constraint
Layer: [Contracts Core](https://banes-lab.com/records/layer/contracts-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lexicon-protocol-contract

Listed in [Lexicon terms](https://banes-lab.com/api/records/lexicon.md), after [Extensible Schema](https://banes-lab.com/records/lexicon/extensible-schema.md) and before [Result Validation](https://banes-lab.com/records/lexicon/result-validation.md).

## Category

- [Contracts / Interfaces / Compatibility](https://banes-lab.com/records/lexicon-category/contracts-interfaces-compatibility.md)

## Required by

- [Protocol Compatibility](https://banes-lab.com/records/architecture/protocol-compatibility.md)

## Linked from

- [Contracts / Interfaces / Compatibility](https://banes-lab.com/ontology/principles/architecture-category-contracts-interfaces-compatibility.md)