---
domain: contracts
last_rule_review_commit: no-commit-yet
last_rule_updated_at: 2026-05-24
---

# contracts

## 목적 / 책임

ALT 애플리케이션 레벨 protobuf 계약을 정의한다. proto-socket은 전송 계층으로 두고, ALT 메시지는 `PacketBase.data`에 실릴 payload schema로 관리한다.

## 포함 경로

- `packages/contracts/README.md` - contract direction and compatibility notes
- `packages/contracts/proto/alt/v1/` - versioned protobuf schema source

## 제외 경로

- `packages/domain/` - internal Go domain types
- `services/api/` - runtime socket server implementation
- `apps/client/` - generated or consumed client-side integration

## 주요 구성 요소

- `common.proto` - shared enums, decimal, handshake, and error messages
- `market.proto` - instrument, price, quantity, bar, and market query messages
- `backtest.proto` - backtest run spec, lifecycle, requests, responses, and result messages

## 유지할 패턴

- Prefer additive protobuf changes and reserve removal/renaming for explicit compatibility work.
- Keep schema package under `alt.v1` until a deliberate version bump is planned.
- Keep `option go_package` aligned with the generated Go package path.
- Use explicit version/handshake messages because proto-socket protocol `0.1` does not carry an ALT application version field.

## 다른 도메인과의 경계

- **api**: contracts define payload shape; API decides transport/session behavior.
- **domain-model**: contracts are wire format; domain-model is internal business vocabulary.
- **client**: client consumes generated or mapped contracts; schema source remains here.

## 금지 사항

- Do not hand-edit generated outputs.
- Do not encode runtime server behavior or database concerns in `.proto` comments or fields.
- Do not change field numbers for existing protobuf fields.