# Requirements

## Functional Requirements

**FR1**: The SDK shall expand from the current Product API category to implement all 32 OZON Seller API categories while maintaining backward compatibility with existing Product API usage patterns.

**FR2**: Each new API category shall follow the established architectural pattern of the existing Product API implementation, including category-based file organization, Zod schema validation, and TypeScript strict typing.

**FR3**: The SDK shall use MCP ozon-api-docs server **during development only** to extract accurate API specifications and generate static TypeScript types, Zod schemas, and method implementations that are then compiled into a self-sufficient SDK with no runtime MCP dependencies.

**FR4**: Each API method across all categories shall include comprehensive error handling for 4xx client errors, 429 rate limiting with exponential backoff, and 5xx server errors with retry logic.

**FR5**: The SDK shall provide a unified pagination helper utility that works consistently across all categories that support pagination, eliminating the need for category-specific pagination implementations.

**FR6**: The core HTTP client shall support idempotency keys for all write operations across all categories to ensure safe retry behavior in distributed environments.

**FR7**: All API methods shall include comprehensive JSDoc documentation with practical usage examples specific to each category's business context.

**FR8**: The SDK shall provide optional live testing capabilities behind environment flags, allowing developers to test against real OZON API endpoints while maintaining comprehensive mock testing by default.

## Non-Functional Requirements

**NFR1**: The enhanced SDK must maintain existing performance characteristics with HTTP client response times under 200ms for cached operations and maintain current memory footprint within 20% variance.

**NFR2**: Test coverage shall achieve and maintain 95% or higher across all 32 categories, including unit tests for success/failure scenarios, retry logic validation, and schema validation testing.

**NFR3**: The SDK shall support TypeScript strict mode with `noImplicitAny`, `exactOptionalPropertyTypes`, and `noUncheckedIndexedAccess` enabled across all new category implementations.

**NFR4**: Build and compilation times shall not increase by more than 50% despite the 32x expansion in API surface area, maintaining developer productivity during local development.

**NFR5**: The SDK bundle size shall implement tree-shaking to allow consumers to import only needed categories, preventing unused categories from impacting application bundle size.

**NFR6**: The compiled SDK shall be completely self-contained with no external service dependencies, ensuring that end-users can use the SDK without any MCP server infrastructure or external documentation dependencies.

## Compatibility Requirements

**CR1**: All existing Product API method signatures, return types, and behavior must remain unchanged to ensure zero breaking changes for current SDK consumers.

**CR2**: The existing HTTP client configuration and authentication patterns must be preserved and extended to support all new categories without requiring configuration changes from existing users.

**CR3**: Current error handling patterns and error type hierarchy must be maintained and consistently applied across all new category implementations.

**CR4**: The existing TypeScript type definitions and export structure must remain stable while expanding to include new category types and interfaces.

**CR5**: The final SDK distribution must include all generated types, schemas, and implementations as static code, with MCP servers used only during the build/development process, not during SDK runtime.