---
description: Slice contracts continue; shared contracts are a hard stop
alwaysApply: true
---

# AI Delivery Contracts

**Assumes:** shapes that cross a boundary (API types, schemas, events, shared tokens). Pair with `ai-delivery-guardrails`. Skip token rules on a project with no UI.

If the only consumer is this repo and this work item, the shape is a **slice** contract. Change it inside the work item and list the change as a reversible decision. Continue.

If there is more than one consumer, or a consumer outside this repo, the shape is a **shared** contract. Any change, including an additive one, is hard stop 1. After a human answers, the change is its own reviewed pull request. A breaking change follows expand-and-contract: add the new shape, move each consumer, then remove the old shape. Each step is its own pull request.

## When they disagree

The contract wins. Do not edit a shared contract so your code compiles. Change the caller, or take hard stop 1.

A slice contract may change in the same pull request when every consumer in that pull request is updated and the typecheck passes.

## Tests

Contract tests for a touched package block the pull request the same way a broken build does.

## Adapters

Put an external system behind an adapter. Do not let that system's shape leak into domain code or into a slice contract.

## Reference

A service reference is its OpenAPI document, generated from the code or the contract package. Do not write that reference by hand.

On an existing codebase, type only the boundary the next increment crosses. Until a boundary is typed, current behaviour is the contract. Do not invent a contract the code never had.