id: validate-requests-with-i18n trigger: "when defining or validating Controller request DTOs in foodie_server" confidence: 0.9 domain: "code-style"

source: "explicit-user-instruction"

Validate request data with internationalized messages

Keep request DTOs as data carriers; do not add Bean Validation annotations such as @NotNull, @NotBlank, or @Size to DTO fields.
Do not rely on @Valid or @Validated on Controller DTO parameters to produce validation responses.
Validate business request parameters in the Controller or Service layer.
Resolve every user-facing validation error through the project's internationalization mechanism, such as MessageUtils.message(...); do not hardcode a single-language validation message.

The user explicitly required DTO validation to be avoided because validation error messages must support internationalization on 2026-08-10.