Agent Guidelines for Scrawn Backend

Commands

Test single file:

vitest src/__tests__/unit/path/to/test.test.ts

Runtime: Bun with TypeScript ESNext, strict mode enabled
Imports: Use
```
type
```
keyword for type-only imports (e.g.,
```
import type { Foo } from "..."
```
)
Types: Always use explicit types for function parameters and return values; avoid
```
any
```
Error handling: Use custom error classes (APIKeyError, StorageError, etc.) with static factory methods; always include error type, message, and optional originalError
Validation: Use Zod schemas for all request validation; catch ZodError and convert to domain errors
Logging: Use logger from
```
errors/logger
```
with
```
logOperationInfo
```
and
```
logOperationError
```
; include operation name and context
Testing: Use Vitest with mocks via
```
vi.fn()
```
; mock database transactions in beforeEach; test success, validation errors, and database errors
Naming: camelCase for variables/functions, PascalCase for classes/types/enums, SCREAMING_SNAKE_CASE for constants
Database: Use Drizzle ORM with transactions; validate all inputs before DB operations; handle unique constraint violations explicitly

Test single file:

vitest src/__tests__/unit/path/to/test.test.ts

Runtime: Bun with TypeScript ESNext, strict mode enabled
Imports: Use
```
type
```
keyword for type-only imports (e.g.,
```
import type { Foo } from "..."
```
)
Types: Always use explicit types for function parameters and return values; avoid
```
any
```
Error handling: Use custom error classes (APIKeyError, StorageError, etc.) with static factory methods; always include error type, message, and optional originalError
Validation: Use Zod schemas for all request validation; catch ZodError and convert to domain errors
Logging: Use logger from
```
errors/logger
```
with
```
logOperationInfo
```
and
```
logOperationError
```
; include operation name and context
Testing: Use Vitest with mocks via
```
vi.fn()
```
; mock database transactions in beforeEach; test success, validation errors, and database errors
Naming: camelCase for variables/functions, PascalCase for classes/types/enums, SCREAMING_SNAKE_CASE for constants
Database: Use Drizzle ORM with transactions; validate all inputs before DB operations; handle unique constraint violations explicitly