Added AI skills

.agents/skills/zod/references/schema-use-primitives-correctly.md

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+---
+title: Use Primitive Schemas Correctly
+impact: CRITICAL
+impactDescription: Incorrect primitive selection causes validation to pass on wrong types; using z.any() or z.unknown() loses all type safety
+tags: schema, primitives, types, basics
+---
+
+## Use Primitive Schemas Correctly
+
+Zod provides specific schemas for each primitive type. Using the wrong schema (e.g., `z.string()` when you need `z.number()`) or falling back to `z.any()` defeats the purpose of validation entirely, allowing corrupt data through.
+
+**Incorrect (wrong primitive or any):**
+
+```typescript
+import { z } from 'zod'
+
+// Using any loses all type safety
+const userSchema = z.object({
+  id: z.any(),  // Accepts anything - no validation
+  age: z.string(),  // Wrong type - age should be number
+  active: z.any(),  // Should be boolean
+})
+
+// This passes validation but data is wrong
+userSchema.parse({ id: null, age: "twenty", active: "yes" })
+// Result: { id: null, age: "twenty", active: "yes" }
+```
+
+**Correct (specific primitives):**
+
+```typescript
+import { z } from 'zod'
+
+const userSchema = z.object({
+  id: z.string().uuid(),  // Specific format validation
+  age: z.number().int().positive(),  // Correct type with constraints
+  active: z.boolean(),  // Exact boolean type
+})
+
+// Now invalid data is rejected
+userSchema.parse({ id: null, age: "twenty", active: "yes" })
+// Throws ZodError with specific field errors
+```
+
+**Available primitive schemas:**
+- `z.string()` - strings with optional regex, min, max, email, url, uuid
+- `z.number()` - numbers with optional int, positive, negative, min, max
+- `z.bigint()` - BigInt values
+- `z.boolean()` - true/false only
+- `z.date()` - Date objects
+- `z.symbol()` - Symbol type
+- `z.undefined()` - undefined only
+- `z.null()` - null only
+- `z.void()` - undefined (for function returns)
+- `z.never()` - no valid value
+
+**When NOT to use this pattern:**
+- When you genuinely need to accept any value (rare - consider `z.unknown()` instead)
+- When migrating legacy code incrementally (use `z.any()` temporarily, then fix)
+
+Reference: [Zod Primitives](https://zod.dev/api#primitives)