Validation (Zod + Guards)

Consistent validation at boundaries: Zod for complex schemas, small guards for
simple runtime checks.

When to Use

Use this skill when:

• Validating API responses or external data in services
• Validating request/input shapes at boundaries (e.g. route handlers, SDK)
• Adding or refactoring utils/validation/ helpers
• Defining Zod schemas alongside types in types/<area>/

Non-Negotiables (MUST)

• Services: validate API/external data with Zod schemas (e.g.
  .safeParse()).
• Utils: keep small coercion/guard helpers under utils/validation/ (one
  function per file).
• Types: Zod schemas can live in types/<area>/; infer types with
  z.infer<typeof Schema>.
• Prefer unknown inputs at boundaries + explicit narrowing.
• No inline validation logic inside components/hooks.

Rules

Boundaries & Placement

• validation-boundaries - Where validation lives (services, utils, types)

Zod Schemas (Complex Validation)

• validation-zod-schemas - Using Zod for complex validation with
  .safeParse()
• validation-zod-types - Inferring types from Zod schemas with z.infer

Guard Helpers (Simple Runtime Checks)

• validation-guard-helpers - Creating simple guard functions with type
  predicates
• validation-guard-examples - Recommended guard helpers (isRecord,
  isNonEmptyString, etc.)

Anti-Patterns

• validation-no-inline - No inline validation logic in components/hooks

Related Skills

• busirocket-nextjs - Validation in route handlers
• busirocket-core-conventions - File boundaries and structure

How to Use

Read individual rule files for detailed explanations and code examples:

rules/validation-boundaries.md
rules/validation-zod-schemas.md
rules/validation-guard-helpers.md

Each rule file contains:

• Brief explanation of why it matters
• Code examples (correct and incorrect patterns)
• Additional context and best practices