Contracts (packages/contracts)

The contracts package defines shared API schemas and types that are consumed by both the API server and client applications. All validation is done with effect/Schema. Zod is banned from the project.

Purpose

Contracts provide a single source of truth for request/response payload shapes, enum types and value sets (such as task statuses, invitation statuses, and member roles), and shared type definitions imported by domain and API layers.

Usage

Contracts are imported by the API routes for request validation and by the domain layer for type definitions:

// Used in domain layer
import { type TaskStatus, taskStatuses } from '@tx-agent-kit/contracts'

// Used in API route validation
import { CreateWorkspaceSchema } from '@tx-agent-kit/contracts'

Schema-First Boundaries

The project enforces schema-first validation at all system boundaries. Rather than using raw types, data crossing trust boundaries (API input, database results) must be decoded through effect/Schema:

import { Schema } from 'effect'

export const TaskStatusSchema = Schema.Literal('open', 'in_progress', 'done', 'cancelled')
export type TaskStatus = Schema.Schema.Type<typeof TaskStatusSchema>

export const taskStatuses = ['open', 'in_progress', 'done', 'cancelled'] as const

Governance

effect/Schema is the only validation library allowed; Zod imports will fail lint checks. Contract types are consumed by packages/core domain layers through re-exports. The API server's openapi.json is generated from these contract definitions, ensuring the spec always matches the runtime validation.