---
title: "ADR 0004: Har is a contract before a fork"
description: "Require demonstrated incompatibility before owning database infrastructure."
navLabel: "ADR 0004"
order: 104
nav: false
eyebrow: "Decision"
status: "accepted"
theme: "main"
visibility: "public"
---

## Context

Instant's open-source realtime relational model appears close to Pre's needs, and a Pre-native fork could be named Har.

## Decision

Har first names the Pre-facing source, query, relation, permission, event, sync, and export contracts. Instant may implement those contracts through an adapter.

A code fork occurs only after a real vertical slice proves a material requirement cannot reasonably live above Instant.

## Consequences

- The architecture is not prematurely coupled to a fork.
- Real requirements determine infrastructure ownership.
- HARnest, Presertion, Stow, and the CLI target Har contracts rather than Instant-specific assumptions.